2006-02-01 09:29:18 +07:00
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/* arch/sparc64/mm/tsb.c
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*
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2008-08-03 14:01:05 +07:00
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* Copyright (C) 2006, 2008 David S. Miller <davem@davemloft.net>
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2006-02-01 09:29:18 +07:00
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*/
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#include <linux/kernel.h>
|
2008-08-03 14:01:05 +07:00
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|
#include <linux/preempt.h>
|
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 15:04:11 +07:00
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#include <linux/slab.h>
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2017-02-04 06:16:44 +07:00
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#include <linux/mm_types.h>
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2006-02-01 09:29:18 +07:00
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#include <asm/page.h>
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2006-02-01 09:31:20 +07:00
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#include <asm/pgtable.h>
|
sparc64: Fix race in TLB batch processing.
As reported by Dave Kleikamp, when we emit cross calls to do batched
TLB flush processing we have a race because we do not synchronize on
the sibling cpus completing the cross call.
So meanwhile the TLB batch can be reset (tb->tlb_nr set to zero, etc.)
and either flushes are missed or flushes will flush the wrong
addresses.
Fix this by using generic infrastructure to synchonize on the
completion of the cross call.
This first required getting the flush_tlb_pending() call out from
switch_to() which operates with locks held and interrupts disabled.
The problem is that smp_call_function_many() cannot be invoked with
IRQs disabled and this is explicitly checked for with WARN_ON_ONCE().
We get the batch processing outside of locked IRQ disabled sections by
using some ideas from the powerpc port. Namely, we only batch inside
of arch_{enter,leave}_lazy_mmu_mode() calls. If we're not in such a
region, we flush TLBs synchronously.
1) Get rid of xcall_flush_tlb_pending and per-cpu type
implementations.
2) Do TLB batch cross calls instead via:
smp_call_function_many()
tlb_pending_func()
__flush_tlb_pending()
3) Batch only in lazy mmu sequences:
a) Add 'active' member to struct tlb_batch
b) Define __HAVE_ARCH_ENTER_LAZY_MMU_MODE
c) Set 'active' in arch_enter_lazy_mmu_mode()
d) Run batch and clear 'active' in arch_leave_lazy_mmu_mode()
e) Check 'active' in tlb_batch_add_one() and do a synchronous
flush if it's clear.
4) Add infrastructure for synchronous TLB page flushes.
a) Implement __flush_tlb_page and per-cpu variants, patch
as needed.
b) Likewise for xcall_flush_tlb_page.
c) Implement smp_flush_tlb_page() to invoke the cross-call.
d) Wire up global_flush_tlb_page() to the right routine based
upon CONFIG_SMP
5) It turns out that singleton batches are very common, 2 out of every
3 batch flushes have only a single entry in them.
The batch flush waiting is very expensive, both because of the poll
on sibling cpu completeion, as well as because passing the tlb batch
pointer to the sibling cpus invokes a shared memory dereference.
Therefore, in flush_tlb_pending(), if there is only one entry in
the batch perform a completely asynchronous global_flush_tlb_page()
instead.
Reported-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2013-04-20 04:26:26 +07:00
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|
#include <asm/mmu_context.h>
|
2014-05-17 04:26:02 +07:00
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#include <asm/setup.h>
|
2006-02-01 09:31:38 +07:00
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|
#include <asm/tsb.h>
|
sparc64: Fix race in TLB batch processing.
As reported by Dave Kleikamp, when we emit cross calls to do batched
TLB flush processing we have a race because we do not synchronize on
the sibling cpus completing the cross call.
So meanwhile the TLB batch can be reset (tb->tlb_nr set to zero, etc.)
and either flushes are missed or flushes will flush the wrong
addresses.
Fix this by using generic infrastructure to synchonize on the
completion of the cross call.
This first required getting the flush_tlb_pending() call out from
switch_to() which operates with locks held and interrupts disabled.
The problem is that smp_call_function_many() cannot be invoked with
IRQs disabled and this is explicitly checked for with WARN_ON_ONCE().
We get the batch processing outside of locked IRQ disabled sections by
using some ideas from the powerpc port. Namely, we only batch inside
of arch_{enter,leave}_lazy_mmu_mode() calls. If we're not in such a
region, we flush TLBs synchronously.
1) Get rid of xcall_flush_tlb_pending and per-cpu type
implementations.
2) Do TLB batch cross calls instead via:
smp_call_function_many()
tlb_pending_func()
__flush_tlb_pending()
3) Batch only in lazy mmu sequences:
a) Add 'active' member to struct tlb_batch
b) Define __HAVE_ARCH_ENTER_LAZY_MMU_MODE
c) Set 'active' in arch_enter_lazy_mmu_mode()
d) Run batch and clear 'active' in arch_leave_lazy_mmu_mode()
e) Check 'active' in tlb_batch_add_one() and do a synchronous
flush if it's clear.
4) Add infrastructure for synchronous TLB page flushes.
a) Implement __flush_tlb_page and per-cpu variants, patch
as needed.
b) Likewise for xcall_flush_tlb_page.
c) Implement smp_flush_tlb_page() to invoke the cross-call.
d) Wire up global_flush_tlb_page() to the right routine based
upon CONFIG_SMP
5) It turns out that singleton batches are very common, 2 out of every
3 batch flushes have only a single entry in them.
The batch flush waiting is very expensive, both because of the poll
on sibling cpu completeion, as well as because passing the tlb batch
pointer to the sibling cpus invokes a shared memory dereference.
Therefore, in flush_tlb_pending(), if there is only one entry in
the batch perform a completely asynchronous global_flush_tlb_page()
instead.
Reported-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2013-04-20 04:26:26 +07:00
|
|
|
#include <asm/tlb.h>
|
2006-03-19 09:12:42 +07:00
|
|
|
#include <asm/oplib.h>
|
2006-02-01 09:29:18 +07:00
|
|
|
|
|
|
|
|
extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES];
|
|
|
|
|
|
2006-03-22 15:49:59 +07:00
|
|
|
static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long hash_shift, unsigned long nentries)
|
2006-02-01 09:29:18 +07:00
|
|
|
{
|
2006-03-22 15:49:59 +07:00
|
|
|
vaddr >>= hash_shift;
|
2006-02-01 09:31:20 +07:00
|
|
|
return vaddr & (nentries - 1);
|
2006-02-01 09:29:18 +07:00
|
|
|
}
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|
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|
2006-02-18 09:01:02 +07:00
|
|
|
static inline int tag_compare(unsigned long tag, unsigned long vaddr)
|
2006-02-01 09:29:18 +07:00
|
|
|
{
|
2006-02-18 09:01:02 +07:00
|
|
|
return (tag == (vaddr >> 22));
|
2006-02-01 09:29:18 +07:00
|
|
|
}
|
|
|
|
|
|
2016-10-26 09:43:17 +07:00
|
|
|
static void flush_tsb_kernel_range_scan(unsigned long start, unsigned long end)
|
|
|
|
|
{
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|
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unsigned long idx;
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for (idx = 0; idx < KERNEL_TSB_NENTRIES; idx++) {
|
|
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struct tsb *ent = &swapper_tsb[idx];
|
|
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unsigned long match = idx << 13;
|
|
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|
match |= (ent->tag << 22);
|
|
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|
if (match >= start && match < end)
|
|
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|
ent->tag = (1UL << TSB_TAG_INVALID_BIT);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2006-02-01 09:29:18 +07:00
|
|
|
/* TSB flushes need only occur on the processor initiating the address
|
|
|
|
|
* space modification, not on each cpu the address space has run on.
|
|
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|
* Only the TLB flush needs that treatment.
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
void flush_tsb_kernel_range(unsigned long start, unsigned long end)
|
|
|
|
|
{
|
|
|
|
|
unsigned long v;
|
|
|
|
|
|
2016-10-26 09:43:17 +07:00
|
|
|
if ((end - start) >> PAGE_SHIFT >= 2 * KERNEL_TSB_NENTRIES)
|
|
|
|
|
return flush_tsb_kernel_range_scan(start, end);
|
|
|
|
|
|
2006-02-01 09:29:18 +07:00
|
|
|
for (v = start; v < end; v += PAGE_SIZE) {
|
2006-03-22 15:49:59 +07:00
|
|
|
unsigned long hash = tsb_hash(v, PAGE_SHIFT,
|
|
|
|
|
KERNEL_TSB_NENTRIES);
|
2006-02-01 09:31:20 +07:00
|
|
|
struct tsb *ent = &swapper_tsb[hash];
|
2006-02-01 09:29:18 +07:00
|
|
|
|
2008-11-16 04:33:25 +07:00
|
|
|
if (tag_compare(ent->tag, v))
|
2006-02-18 09:01:02 +07:00
|
|
|
ent->tag = (1UL << TSB_TAG_INVALID_BIT);
|
2006-02-01 09:29:18 +07:00
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
sparc64: Fix race in TLB batch processing.
As reported by Dave Kleikamp, when we emit cross calls to do batched
TLB flush processing we have a race because we do not synchronize on
the sibling cpus completing the cross call.
So meanwhile the TLB batch can be reset (tb->tlb_nr set to zero, etc.)
and either flushes are missed or flushes will flush the wrong
addresses.
Fix this by using generic infrastructure to synchonize on the
completion of the cross call.
This first required getting the flush_tlb_pending() call out from
switch_to() which operates with locks held and interrupts disabled.
The problem is that smp_call_function_many() cannot be invoked with
IRQs disabled and this is explicitly checked for with WARN_ON_ONCE().
We get the batch processing outside of locked IRQ disabled sections by
using some ideas from the powerpc port. Namely, we only batch inside
of arch_{enter,leave}_lazy_mmu_mode() calls. If we're not in such a
region, we flush TLBs synchronously.
1) Get rid of xcall_flush_tlb_pending and per-cpu type
implementations.
2) Do TLB batch cross calls instead via:
smp_call_function_many()
tlb_pending_func()
__flush_tlb_pending()
3) Batch only in lazy mmu sequences:
a) Add 'active' member to struct tlb_batch
b) Define __HAVE_ARCH_ENTER_LAZY_MMU_MODE
c) Set 'active' in arch_enter_lazy_mmu_mode()
d) Run batch and clear 'active' in arch_leave_lazy_mmu_mode()
e) Check 'active' in tlb_batch_add_one() and do a synchronous
flush if it's clear.
4) Add infrastructure for synchronous TLB page flushes.
a) Implement __flush_tlb_page and per-cpu variants, patch
as needed.
b) Likewise for xcall_flush_tlb_page.
c) Implement smp_flush_tlb_page() to invoke the cross-call.
d) Wire up global_flush_tlb_page() to the right routine based
upon CONFIG_SMP
5) It turns out that singleton batches are very common, 2 out of every
3 batch flushes have only a single entry in them.
The batch flush waiting is very expensive, both because of the poll
on sibling cpu completeion, as well as because passing the tlb batch
pointer to the sibling cpus invokes a shared memory dereference.
Therefore, in flush_tlb_pending(), if there is only one entry in
the batch perform a completely asynchronous global_flush_tlb_page()
instead.
Reported-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2013-04-20 04:26:26 +07:00
|
|
|
static void __flush_tsb_one_entry(unsigned long tsb, unsigned long v,
|
|
|
|
|
unsigned long hash_shift,
|
|
|
|
|
unsigned long nentries)
|
2006-02-01 09:29:18 +07:00
|
|
|
{
|
sparc64: Fix race in TLB batch processing.
As reported by Dave Kleikamp, when we emit cross calls to do batched
TLB flush processing we have a race because we do not synchronize on
the sibling cpus completing the cross call.
So meanwhile the TLB batch can be reset (tb->tlb_nr set to zero, etc.)
and either flushes are missed or flushes will flush the wrong
addresses.
Fix this by using generic infrastructure to synchonize on the
completion of the cross call.
This first required getting the flush_tlb_pending() call out from
switch_to() which operates with locks held and interrupts disabled.
The problem is that smp_call_function_many() cannot be invoked with
IRQs disabled and this is explicitly checked for with WARN_ON_ONCE().
We get the batch processing outside of locked IRQ disabled sections by
using some ideas from the powerpc port. Namely, we only batch inside
of arch_{enter,leave}_lazy_mmu_mode() calls. If we're not in such a
region, we flush TLBs synchronously.
1) Get rid of xcall_flush_tlb_pending and per-cpu type
implementations.
2) Do TLB batch cross calls instead via:
smp_call_function_many()
tlb_pending_func()
__flush_tlb_pending()
3) Batch only in lazy mmu sequences:
a) Add 'active' member to struct tlb_batch
b) Define __HAVE_ARCH_ENTER_LAZY_MMU_MODE
c) Set 'active' in arch_enter_lazy_mmu_mode()
d) Run batch and clear 'active' in arch_leave_lazy_mmu_mode()
e) Check 'active' in tlb_batch_add_one() and do a synchronous
flush if it's clear.
4) Add infrastructure for synchronous TLB page flushes.
a) Implement __flush_tlb_page and per-cpu variants, patch
as needed.
b) Likewise for xcall_flush_tlb_page.
c) Implement smp_flush_tlb_page() to invoke the cross-call.
d) Wire up global_flush_tlb_page() to the right routine based
upon CONFIG_SMP
5) It turns out that singleton batches are very common, 2 out of every
3 batch flushes have only a single entry in them.
The batch flush waiting is very expensive, both because of the poll
on sibling cpu completeion, as well as because passing the tlb batch
pointer to the sibling cpus invokes a shared memory dereference.
Therefore, in flush_tlb_pending(), if there is only one entry in
the batch perform a completely asynchronous global_flush_tlb_page()
instead.
Reported-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2013-04-20 04:26:26 +07:00
|
|
|
unsigned long tag, ent, hash;
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
|
sparc64: Fix race in TLB batch processing.
As reported by Dave Kleikamp, when we emit cross calls to do batched
TLB flush processing we have a race because we do not synchronize on
the sibling cpus completing the cross call.
So meanwhile the TLB batch can be reset (tb->tlb_nr set to zero, etc.)
and either flushes are missed or flushes will flush the wrong
addresses.
Fix this by using generic infrastructure to synchonize on the
completion of the cross call.
This first required getting the flush_tlb_pending() call out from
switch_to() which operates with locks held and interrupts disabled.
The problem is that smp_call_function_many() cannot be invoked with
IRQs disabled and this is explicitly checked for with WARN_ON_ONCE().
We get the batch processing outside of locked IRQ disabled sections by
using some ideas from the powerpc port. Namely, we only batch inside
of arch_{enter,leave}_lazy_mmu_mode() calls. If we're not in such a
region, we flush TLBs synchronously.
1) Get rid of xcall_flush_tlb_pending and per-cpu type
implementations.
2) Do TLB batch cross calls instead via:
smp_call_function_many()
tlb_pending_func()
__flush_tlb_pending()
3) Batch only in lazy mmu sequences:
a) Add 'active' member to struct tlb_batch
b) Define __HAVE_ARCH_ENTER_LAZY_MMU_MODE
c) Set 'active' in arch_enter_lazy_mmu_mode()
d) Run batch and clear 'active' in arch_leave_lazy_mmu_mode()
e) Check 'active' in tlb_batch_add_one() and do a synchronous
flush if it's clear.
4) Add infrastructure for synchronous TLB page flushes.
a) Implement __flush_tlb_page and per-cpu variants, patch
as needed.
b) Likewise for xcall_flush_tlb_page.
c) Implement smp_flush_tlb_page() to invoke the cross-call.
d) Wire up global_flush_tlb_page() to the right routine based
upon CONFIG_SMP
5) It turns out that singleton batches are very common, 2 out of every
3 batch flushes have only a single entry in them.
The batch flush waiting is very expensive, both because of the poll
on sibling cpu completeion, as well as because passing the tlb batch
pointer to the sibling cpus invokes a shared memory dereference.
Therefore, in flush_tlb_pending(), if there is only one entry in
the batch perform a completely asynchronous global_flush_tlb_page()
instead.
Reported-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2013-04-20 04:26:26 +07:00
|
|
|
v &= ~0x1UL;
|
|
|
|
|
hash = tsb_hash(v, hash_shift, nentries);
|
|
|
|
|
ent = tsb + (hash * sizeof(struct tsb));
|
|
|
|
|
tag = (v >> 22UL);
|
2006-02-01 09:29:18 +07:00
|
|
|
|
sparc64: Fix race in TLB batch processing.
As reported by Dave Kleikamp, when we emit cross calls to do batched
TLB flush processing we have a race because we do not synchronize on
the sibling cpus completing the cross call.
So meanwhile the TLB batch can be reset (tb->tlb_nr set to zero, etc.)
and either flushes are missed or flushes will flush the wrong
addresses.
Fix this by using generic infrastructure to synchonize on the
completion of the cross call.
This first required getting the flush_tlb_pending() call out from
switch_to() which operates with locks held and interrupts disabled.
The problem is that smp_call_function_many() cannot be invoked with
IRQs disabled and this is explicitly checked for with WARN_ON_ONCE().
We get the batch processing outside of locked IRQ disabled sections by
using some ideas from the powerpc port. Namely, we only batch inside
of arch_{enter,leave}_lazy_mmu_mode() calls. If we're not in such a
region, we flush TLBs synchronously.
1) Get rid of xcall_flush_tlb_pending and per-cpu type
implementations.
2) Do TLB batch cross calls instead via:
smp_call_function_many()
tlb_pending_func()
__flush_tlb_pending()
3) Batch only in lazy mmu sequences:
a) Add 'active' member to struct tlb_batch
b) Define __HAVE_ARCH_ENTER_LAZY_MMU_MODE
c) Set 'active' in arch_enter_lazy_mmu_mode()
d) Run batch and clear 'active' in arch_leave_lazy_mmu_mode()
e) Check 'active' in tlb_batch_add_one() and do a synchronous
flush if it's clear.
4) Add infrastructure for synchronous TLB page flushes.
a) Implement __flush_tlb_page and per-cpu variants, patch
as needed.
b) Likewise for xcall_flush_tlb_page.
c) Implement smp_flush_tlb_page() to invoke the cross-call.
d) Wire up global_flush_tlb_page() to the right routine based
upon CONFIG_SMP
5) It turns out that singleton batches are very common, 2 out of every
3 batch flushes have only a single entry in them.
The batch flush waiting is very expensive, both because of the poll
on sibling cpu completeion, as well as because passing the tlb batch
pointer to the sibling cpus invokes a shared memory dereference.
Therefore, in flush_tlb_pending(), if there is only one entry in
the batch perform a completely asynchronous global_flush_tlb_page()
instead.
Reported-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2013-04-20 04:26:26 +07:00
|
|
|
tsb_flush(ent, tag);
|
|
|
|
|
}
|
2006-02-01 09:29:18 +07:00
|
|
|
|
sparc64: Fix race in TLB batch processing.
As reported by Dave Kleikamp, when we emit cross calls to do batched
TLB flush processing we have a race because we do not synchronize on
the sibling cpus completing the cross call.
So meanwhile the TLB batch can be reset (tb->tlb_nr set to zero, etc.)
and either flushes are missed or flushes will flush the wrong
addresses.
Fix this by using generic infrastructure to synchonize on the
completion of the cross call.
This first required getting the flush_tlb_pending() call out from
switch_to() which operates with locks held and interrupts disabled.
The problem is that smp_call_function_many() cannot be invoked with
IRQs disabled and this is explicitly checked for with WARN_ON_ONCE().
We get the batch processing outside of locked IRQ disabled sections by
using some ideas from the powerpc port. Namely, we only batch inside
of arch_{enter,leave}_lazy_mmu_mode() calls. If we're not in such a
region, we flush TLBs synchronously.
1) Get rid of xcall_flush_tlb_pending and per-cpu type
implementations.
2) Do TLB batch cross calls instead via:
smp_call_function_many()
tlb_pending_func()
__flush_tlb_pending()
3) Batch only in lazy mmu sequences:
a) Add 'active' member to struct tlb_batch
b) Define __HAVE_ARCH_ENTER_LAZY_MMU_MODE
c) Set 'active' in arch_enter_lazy_mmu_mode()
d) Run batch and clear 'active' in arch_leave_lazy_mmu_mode()
e) Check 'active' in tlb_batch_add_one() and do a synchronous
flush if it's clear.
4) Add infrastructure for synchronous TLB page flushes.
a) Implement __flush_tlb_page and per-cpu variants, patch
as needed.
b) Likewise for xcall_flush_tlb_page.
c) Implement smp_flush_tlb_page() to invoke the cross-call.
d) Wire up global_flush_tlb_page() to the right routine based
upon CONFIG_SMP
5) It turns out that singleton batches are very common, 2 out of every
3 batch flushes have only a single entry in them.
The batch flush waiting is very expensive, both because of the poll
on sibling cpu completeion, as well as because passing the tlb batch
pointer to the sibling cpus invokes a shared memory dereference.
Therefore, in flush_tlb_pending(), if there is only one entry in
the batch perform a completely asynchronous global_flush_tlb_page()
instead.
Reported-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2013-04-20 04:26:26 +07:00
|
|
|
static void __flush_tsb_one(struct tlb_batch *tb, unsigned long hash_shift,
|
|
|
|
|
unsigned long tsb, unsigned long nentries)
|
|
|
|
|
{
|
|
|
|
|
unsigned long i;
|
2006-02-02 06:55:21 +07:00
|
|
|
|
sparc64: Fix race in TLB batch processing.
As reported by Dave Kleikamp, when we emit cross calls to do batched
TLB flush processing we have a race because we do not synchronize on
the sibling cpus completing the cross call.
So meanwhile the TLB batch can be reset (tb->tlb_nr set to zero, etc.)
and either flushes are missed or flushes will flush the wrong
addresses.
Fix this by using generic infrastructure to synchonize on the
completion of the cross call.
This first required getting the flush_tlb_pending() call out from
switch_to() which operates with locks held and interrupts disabled.
The problem is that smp_call_function_many() cannot be invoked with
IRQs disabled and this is explicitly checked for with WARN_ON_ONCE().
We get the batch processing outside of locked IRQ disabled sections by
using some ideas from the powerpc port. Namely, we only batch inside
of arch_{enter,leave}_lazy_mmu_mode() calls. If we're not in such a
region, we flush TLBs synchronously.
1) Get rid of xcall_flush_tlb_pending and per-cpu type
implementations.
2) Do TLB batch cross calls instead via:
smp_call_function_many()
tlb_pending_func()
__flush_tlb_pending()
3) Batch only in lazy mmu sequences:
a) Add 'active' member to struct tlb_batch
b) Define __HAVE_ARCH_ENTER_LAZY_MMU_MODE
c) Set 'active' in arch_enter_lazy_mmu_mode()
d) Run batch and clear 'active' in arch_leave_lazy_mmu_mode()
e) Check 'active' in tlb_batch_add_one() and do a synchronous
flush if it's clear.
4) Add infrastructure for synchronous TLB page flushes.
a) Implement __flush_tlb_page and per-cpu variants, patch
as needed.
b) Likewise for xcall_flush_tlb_page.
c) Implement smp_flush_tlb_page() to invoke the cross-call.
d) Wire up global_flush_tlb_page() to the right routine based
upon CONFIG_SMP
5) It turns out that singleton batches are very common, 2 out of every
3 batch flushes have only a single entry in them.
The batch flush waiting is very expensive, both because of the poll
on sibling cpu completeion, as well as because passing the tlb batch
pointer to the sibling cpus invokes a shared memory dereference.
Therefore, in flush_tlb_pending(), if there is only one entry in
the batch perform a completely asynchronous global_flush_tlb_page()
instead.
Reported-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2013-04-20 04:26:26 +07:00
|
|
|
for (i = 0; i < tb->tlb_nr; i++)
|
|
|
|
|
__flush_tsb_one_entry(tsb, tb->vaddrs[i], hash_shift, nentries);
|
2006-03-22 15:49:59 +07:00
|
|
|
}
|
|
|
|
|
|
2017-02-02 07:16:36 +07:00
|
|
|
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
|
|
|
|
|
static void __flush_huge_tsb_one_entry(unsigned long tsb, unsigned long v,
|
|
|
|
|
unsigned long hash_shift,
|
|
|
|
|
unsigned long nentries,
|
|
|
|
|
unsigned int hugepage_shift)
|
|
|
|
|
{
|
|
|
|
|
unsigned int hpage_entries;
|
|
|
|
|
unsigned int i;
|
|
|
|
|
|
|
|
|
|
hpage_entries = 1 << (hugepage_shift - hash_shift);
|
|
|
|
|
for (i = 0; i < hpage_entries; i++)
|
|
|
|
|
__flush_tsb_one_entry(tsb, v + (i << hash_shift), hash_shift,
|
|
|
|
|
nentries);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void __flush_huge_tsb_one(struct tlb_batch *tb, unsigned long hash_shift,
|
|
|
|
|
unsigned long tsb, unsigned long nentries,
|
|
|
|
|
unsigned int hugepage_shift)
|
|
|
|
|
{
|
|
|
|
|
unsigned long i;
|
|
|
|
|
|
|
|
|
|
for (i = 0; i < tb->tlb_nr; i++)
|
|
|
|
|
__flush_huge_tsb_one_entry(tsb, tb->vaddrs[i], hash_shift,
|
|
|
|
|
nentries, hugepage_shift);
|
|
|
|
|
}
|
|
|
|
|
#endif
|
|
|
|
|
|
2011-05-25 07:11:50 +07:00
|
|
|
void flush_tsb_user(struct tlb_batch *tb)
|
2006-03-22 15:49:59 +07:00
|
|
|
{
|
2011-05-25 07:11:50 +07:00
|
|
|
struct mm_struct *mm = tb->mm;
|
2006-03-22 15:49:59 +07:00
|
|
|
unsigned long nentries, base, flags;
|
|
|
|
|
|
|
|
|
|
spin_lock_irqsave(&mm->context.lock, flags);
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
|
2017-04-01 05:48:53 +07:00
|
|
|
if (tb->hugepage_shift < REAL_HPAGE_SHIFT) {
|
2016-03-31 01:17:13 +07:00
|
|
|
base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
|
|
|
|
|
nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
|
|
|
|
|
if (tlb_type == cheetah_plus || tlb_type == hypervisor)
|
|
|
|
|
base = __pa(base);
|
2017-02-24 18:03:16 +07:00
|
|
|
if (tb->hugepage_shift == PAGE_SHIFT)
|
|
|
|
|
__flush_tsb_one(tb, PAGE_SHIFT, base, nentries);
|
|
|
|
|
#if defined(CONFIG_HUGETLB_PAGE)
|
|
|
|
|
else
|
|
|
|
|
__flush_huge_tsb_one(tb, PAGE_SHIFT, base, nentries,
|
|
|
|
|
tb->hugepage_shift);
|
|
|
|
|
#endif
|
2016-03-31 01:17:13 +07:00
|
|
|
}
|
2012-10-09 06:34:29 +07:00
|
|
|
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
|
2017-02-02 07:16:36 +07:00
|
|
|
else if (mm->context.tsb_block[MM_TSB_HUGE].tsb) {
|
2006-03-22 15:49:59 +07:00
|
|
|
base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
|
|
|
|
|
nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
|
|
|
|
|
if (tlb_type == cheetah_plus || tlb_type == hypervisor)
|
|
|
|
|
base = __pa(base);
|
2017-02-02 07:16:36 +07:00
|
|
|
__flush_huge_tsb_one(tb, REAL_HPAGE_SHIFT, base, nentries,
|
|
|
|
|
tb->hugepage_shift);
|
2006-03-22 15:49:59 +07:00
|
|
|
}
|
|
|
|
|
#endif
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
spin_unlock_irqrestore(&mm->context.lock, flags);
|
2006-02-01 09:29:18 +07:00
|
|
|
}
|
2006-02-01 09:31:06 +07:00
|
|
|
|
2017-02-02 07:16:36 +07:00
|
|
|
void flush_tsb_user_page(struct mm_struct *mm, unsigned long vaddr,
|
|
|
|
|
unsigned int hugepage_shift)
|
sparc64: Fix race in TLB batch processing.
As reported by Dave Kleikamp, when we emit cross calls to do batched
TLB flush processing we have a race because we do not synchronize on
the sibling cpus completing the cross call.
So meanwhile the TLB batch can be reset (tb->tlb_nr set to zero, etc.)
and either flushes are missed or flushes will flush the wrong
addresses.
Fix this by using generic infrastructure to synchonize on the
completion of the cross call.
This first required getting the flush_tlb_pending() call out from
switch_to() which operates with locks held and interrupts disabled.
The problem is that smp_call_function_many() cannot be invoked with
IRQs disabled and this is explicitly checked for with WARN_ON_ONCE().
We get the batch processing outside of locked IRQ disabled sections by
using some ideas from the powerpc port. Namely, we only batch inside
of arch_{enter,leave}_lazy_mmu_mode() calls. If we're not in such a
region, we flush TLBs synchronously.
1) Get rid of xcall_flush_tlb_pending and per-cpu type
implementations.
2) Do TLB batch cross calls instead via:
smp_call_function_many()
tlb_pending_func()
__flush_tlb_pending()
3) Batch only in lazy mmu sequences:
a) Add 'active' member to struct tlb_batch
b) Define __HAVE_ARCH_ENTER_LAZY_MMU_MODE
c) Set 'active' in arch_enter_lazy_mmu_mode()
d) Run batch and clear 'active' in arch_leave_lazy_mmu_mode()
e) Check 'active' in tlb_batch_add_one() and do a synchronous
flush if it's clear.
4) Add infrastructure for synchronous TLB page flushes.
a) Implement __flush_tlb_page and per-cpu variants, patch
as needed.
b) Likewise for xcall_flush_tlb_page.
c) Implement smp_flush_tlb_page() to invoke the cross-call.
d) Wire up global_flush_tlb_page() to the right routine based
upon CONFIG_SMP
5) It turns out that singleton batches are very common, 2 out of every
3 batch flushes have only a single entry in them.
The batch flush waiting is very expensive, both because of the poll
on sibling cpu completeion, as well as because passing the tlb batch
pointer to the sibling cpus invokes a shared memory dereference.
Therefore, in flush_tlb_pending(), if there is only one entry in
the batch perform a completely asynchronous global_flush_tlb_page()
instead.
Reported-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2013-04-20 04:26:26 +07:00
|
|
|
{
|
|
|
|
|
unsigned long nentries, base, flags;
|
|
|
|
|
|
|
|
|
|
spin_lock_irqsave(&mm->context.lock, flags);
|
|
|
|
|
|
2017-04-01 05:48:53 +07:00
|
|
|
if (hugepage_shift < REAL_HPAGE_SHIFT) {
|
2016-03-31 01:17:13 +07:00
|
|
|
base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
|
|
|
|
|
nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
|
|
|
|
|
if (tlb_type == cheetah_plus || tlb_type == hypervisor)
|
|
|
|
|
base = __pa(base);
|
2017-02-24 18:03:16 +07:00
|
|
|
if (hugepage_shift == PAGE_SHIFT)
|
|
|
|
|
__flush_tsb_one_entry(base, vaddr, PAGE_SHIFT,
|
|
|
|
|
nentries);
|
|
|
|
|
#if defined(CONFIG_HUGETLB_PAGE)
|
|
|
|
|
else
|
|
|
|
|
__flush_huge_tsb_one_entry(base, vaddr, PAGE_SHIFT,
|
|
|
|
|
nentries, hugepage_shift);
|
|
|
|
|
#endif
|
2016-03-31 01:17:13 +07:00
|
|
|
}
|
sparc64: Fix race in TLB batch processing.
As reported by Dave Kleikamp, when we emit cross calls to do batched
TLB flush processing we have a race because we do not synchronize on
the sibling cpus completing the cross call.
So meanwhile the TLB batch can be reset (tb->tlb_nr set to zero, etc.)
and either flushes are missed or flushes will flush the wrong
addresses.
Fix this by using generic infrastructure to synchonize on the
completion of the cross call.
This first required getting the flush_tlb_pending() call out from
switch_to() which operates with locks held and interrupts disabled.
The problem is that smp_call_function_many() cannot be invoked with
IRQs disabled and this is explicitly checked for with WARN_ON_ONCE().
We get the batch processing outside of locked IRQ disabled sections by
using some ideas from the powerpc port. Namely, we only batch inside
of arch_{enter,leave}_lazy_mmu_mode() calls. If we're not in such a
region, we flush TLBs synchronously.
1) Get rid of xcall_flush_tlb_pending and per-cpu type
implementations.
2) Do TLB batch cross calls instead via:
smp_call_function_many()
tlb_pending_func()
__flush_tlb_pending()
3) Batch only in lazy mmu sequences:
a) Add 'active' member to struct tlb_batch
b) Define __HAVE_ARCH_ENTER_LAZY_MMU_MODE
c) Set 'active' in arch_enter_lazy_mmu_mode()
d) Run batch and clear 'active' in arch_leave_lazy_mmu_mode()
e) Check 'active' in tlb_batch_add_one() and do a synchronous
flush if it's clear.
4) Add infrastructure for synchronous TLB page flushes.
a) Implement __flush_tlb_page and per-cpu variants, patch
as needed.
b) Likewise for xcall_flush_tlb_page.
c) Implement smp_flush_tlb_page() to invoke the cross-call.
d) Wire up global_flush_tlb_page() to the right routine based
upon CONFIG_SMP
5) It turns out that singleton batches are very common, 2 out of every
3 batch flushes have only a single entry in them.
The batch flush waiting is very expensive, both because of the poll
on sibling cpu completeion, as well as because passing the tlb batch
pointer to the sibling cpus invokes a shared memory dereference.
Therefore, in flush_tlb_pending(), if there is only one entry in
the batch perform a completely asynchronous global_flush_tlb_page()
instead.
Reported-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2013-04-20 04:26:26 +07:00
|
|
|
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
|
2017-02-02 07:16:36 +07:00
|
|
|
else if (mm->context.tsb_block[MM_TSB_HUGE].tsb) {
|
sparc64: Fix race in TLB batch processing.
As reported by Dave Kleikamp, when we emit cross calls to do batched
TLB flush processing we have a race because we do not synchronize on
the sibling cpus completing the cross call.
So meanwhile the TLB batch can be reset (tb->tlb_nr set to zero, etc.)
and either flushes are missed or flushes will flush the wrong
addresses.
Fix this by using generic infrastructure to synchonize on the
completion of the cross call.
This first required getting the flush_tlb_pending() call out from
switch_to() which operates with locks held and interrupts disabled.
The problem is that smp_call_function_many() cannot be invoked with
IRQs disabled and this is explicitly checked for with WARN_ON_ONCE().
We get the batch processing outside of locked IRQ disabled sections by
using some ideas from the powerpc port. Namely, we only batch inside
of arch_{enter,leave}_lazy_mmu_mode() calls. If we're not in such a
region, we flush TLBs synchronously.
1) Get rid of xcall_flush_tlb_pending and per-cpu type
implementations.
2) Do TLB batch cross calls instead via:
smp_call_function_many()
tlb_pending_func()
__flush_tlb_pending()
3) Batch only in lazy mmu sequences:
a) Add 'active' member to struct tlb_batch
b) Define __HAVE_ARCH_ENTER_LAZY_MMU_MODE
c) Set 'active' in arch_enter_lazy_mmu_mode()
d) Run batch and clear 'active' in arch_leave_lazy_mmu_mode()
e) Check 'active' in tlb_batch_add_one() and do a synchronous
flush if it's clear.
4) Add infrastructure for synchronous TLB page flushes.
a) Implement __flush_tlb_page and per-cpu variants, patch
as needed.
b) Likewise for xcall_flush_tlb_page.
c) Implement smp_flush_tlb_page() to invoke the cross-call.
d) Wire up global_flush_tlb_page() to the right routine based
upon CONFIG_SMP
5) It turns out that singleton batches are very common, 2 out of every
3 batch flushes have only a single entry in them.
The batch flush waiting is very expensive, both because of the poll
on sibling cpu completeion, as well as because passing the tlb batch
pointer to the sibling cpus invokes a shared memory dereference.
Therefore, in flush_tlb_pending(), if there is only one entry in
the batch perform a completely asynchronous global_flush_tlb_page()
instead.
Reported-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2013-04-20 04:26:26 +07:00
|
|
|
base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
|
|
|
|
|
nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
|
|
|
|
|
if (tlb_type == cheetah_plus || tlb_type == hypervisor)
|
|
|
|
|
base = __pa(base);
|
2017-02-02 07:16:36 +07:00
|
|
|
__flush_huge_tsb_one_entry(base, vaddr, REAL_HPAGE_SHIFT,
|
|
|
|
|
nentries, hugepage_shift);
|
sparc64: Fix race in TLB batch processing.
As reported by Dave Kleikamp, when we emit cross calls to do batched
TLB flush processing we have a race because we do not synchronize on
the sibling cpus completing the cross call.
So meanwhile the TLB batch can be reset (tb->tlb_nr set to zero, etc.)
and either flushes are missed or flushes will flush the wrong
addresses.
Fix this by using generic infrastructure to synchonize on the
completion of the cross call.
This first required getting the flush_tlb_pending() call out from
switch_to() which operates with locks held and interrupts disabled.
The problem is that smp_call_function_many() cannot be invoked with
IRQs disabled and this is explicitly checked for with WARN_ON_ONCE().
We get the batch processing outside of locked IRQ disabled sections by
using some ideas from the powerpc port. Namely, we only batch inside
of arch_{enter,leave}_lazy_mmu_mode() calls. If we're not in such a
region, we flush TLBs synchronously.
1) Get rid of xcall_flush_tlb_pending and per-cpu type
implementations.
2) Do TLB batch cross calls instead via:
smp_call_function_many()
tlb_pending_func()
__flush_tlb_pending()
3) Batch only in lazy mmu sequences:
a) Add 'active' member to struct tlb_batch
b) Define __HAVE_ARCH_ENTER_LAZY_MMU_MODE
c) Set 'active' in arch_enter_lazy_mmu_mode()
d) Run batch and clear 'active' in arch_leave_lazy_mmu_mode()
e) Check 'active' in tlb_batch_add_one() and do a synchronous
flush if it's clear.
4) Add infrastructure for synchronous TLB page flushes.
a) Implement __flush_tlb_page and per-cpu variants, patch
as needed.
b) Likewise for xcall_flush_tlb_page.
c) Implement smp_flush_tlb_page() to invoke the cross-call.
d) Wire up global_flush_tlb_page() to the right routine based
upon CONFIG_SMP
5) It turns out that singleton batches are very common, 2 out of every
3 batch flushes have only a single entry in them.
The batch flush waiting is very expensive, both because of the poll
on sibling cpu completeion, as well as because passing the tlb batch
pointer to the sibling cpus invokes a shared memory dereference.
Therefore, in flush_tlb_pending(), if there is only one entry in
the batch perform a completely asynchronous global_flush_tlb_page()
instead.
Reported-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2013-04-20 04:26:26 +07:00
|
|
|
}
|
|
|
|
|
#endif
|
|
|
|
|
spin_unlock_irqrestore(&mm->context.lock, flags);
|
|
|
|
|
}
|
|
|
|
|
|
2006-03-22 15:49:59 +07:00
|
|
|
#define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_8K
|
|
|
|
|
#define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_8K
|
|
|
|
|
|
2012-10-09 06:34:29 +07:00
|
|
|
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
|
2006-03-22 15:49:59 +07:00
|
|
|
#define HV_PGSZ_IDX_HUGE HV_PGSZ_IDX_4MB
|
|
|
|
|
#define HV_PGSZ_MASK_HUGE HV_PGSZ_MASK_4MB
|
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_idx, unsigned long tsb_bytes)
|
2006-02-01 09:31:20 +07:00
|
|
|
{
|
|
|
|
|
unsigned long tsb_reg, base, tsb_paddr;
|
|
|
|
|
unsigned long page_sz, tte;
|
|
|
|
|
|
2006-03-22 15:49:59 +07:00
|
|
|
mm->context.tsb_block[tsb_idx].tsb_nentries =
|
|
|
|
|
tsb_bytes / sizeof(struct tsb);
|
2006-02-01 09:31:20 +07:00
|
|
|
|
2014-05-08 04:07:32 +07:00
|
|
|
switch (tsb_idx) {
|
|
|
|
|
case MM_TSB_BASE:
|
|
|
|
|
base = TSBMAP_8K_BASE;
|
|
|
|
|
break;
|
|
|
|
|
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
|
|
|
|
|
case MM_TSB_HUGE:
|
|
|
|
|
base = TSBMAP_4M_BASE;
|
|
|
|
|
break;
|
|
|
|
|
#endif
|
|
|
|
|
default:
|
|
|
|
|
BUG();
|
|
|
|
|
}
|
|
|
|
|
|
2006-02-12 12:57:54 +07:00
|
|
|
tte = pgprot_val(PAGE_KERNEL_LOCKED);
|
2006-03-22 15:49:59 +07:00
|
|
|
tsb_paddr = __pa(mm->context.tsb_block[tsb_idx].tsb);
|
2006-02-02 06:55:21 +07:00
|
|
|
BUG_ON(tsb_paddr & (tsb_bytes - 1UL));
|
2006-02-01 09:31:20 +07:00
|
|
|
|
|
|
|
|
/* Use the smallest page size that can map the whole TSB
|
|
|
|
|
* in one TLB entry.
|
|
|
|
|
*/
|
|
|
|
|
switch (tsb_bytes) {
|
|
|
|
|
case 8192 << 0:
|
|
|
|
|
tsb_reg = 0x0UL;
|
|
|
|
|
#ifdef DCACHE_ALIASING_POSSIBLE
|
|
|
|
|
base += (tsb_paddr & 8192);
|
|
|
|
|
#endif
|
|
|
|
|
page_sz = 8192;
|
|
|
|
|
break;
|
|
|
|
|
|
|
|
|
|
case 8192 << 1:
|
|
|
|
|
tsb_reg = 0x1UL;
|
|
|
|
|
page_sz = 64 * 1024;
|
|
|
|
|
break;
|
|
|
|
|
|
|
|
|
|
case 8192 << 2:
|
|
|
|
|
tsb_reg = 0x2UL;
|
|
|
|
|
page_sz = 64 * 1024;
|
|
|
|
|
break;
|
|
|
|
|
|
|
|
|
|
case 8192 << 3:
|
|
|
|
|
tsb_reg = 0x3UL;
|
|
|
|
|
page_sz = 64 * 1024;
|
|
|
|
|
break;
|
|
|
|
|
|
|
|
|
|
case 8192 << 4:
|
|
|
|
|
tsb_reg = 0x4UL;
|
|
|
|
|
page_sz = 512 * 1024;
|
|
|
|
|
break;
|
|
|
|
|
|
|
|
|
|
case 8192 << 5:
|
|
|
|
|
tsb_reg = 0x5UL;
|
|
|
|
|
page_sz = 512 * 1024;
|
|
|
|
|
break;
|
|
|
|
|
|
|
|
|
|
case 8192 << 6:
|
|
|
|
|
tsb_reg = 0x6UL;
|
|
|
|
|
page_sz = 512 * 1024;
|
|
|
|
|
break;
|
|
|
|
|
|
|
|
|
|
case 8192 << 7:
|
|
|
|
|
tsb_reg = 0x7UL;
|
|
|
|
|
page_sz = 4 * 1024 * 1024;
|
|
|
|
|
break;
|
2006-02-01 09:31:38 +07:00
|
|
|
|
|
|
|
|
default:
|
2007-10-29 14:36:09 +07:00
|
|
|
printk(KERN_ERR "TSB[%s:%d]: Impossible TSB size %lu, killing process.\n",
|
|
|
|
|
current->comm, current->pid, tsb_bytes);
|
|
|
|
|
do_exit(SIGSEGV);
|
2011-06-03 21:45:23 +07:00
|
|
|
}
|
2006-02-12 12:57:54 +07:00
|
|
|
tte |= pte_sz_bits(page_sz);
|
2006-02-01 09:31:20 +07:00
|
|
|
|
2006-02-10 08:21:53 +07:00
|
|
|
if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
|
2006-02-02 06:55:21 +07:00
|
|
|
/* Physical mapping, no locked TLB entry for TSB. */
|
|
|
|
|
tsb_reg |= tsb_paddr;
|
|
|
|
|
|
2006-03-22 15:49:59 +07:00
|
|
|
mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
|
|
|
|
|
mm->context.tsb_block[tsb_idx].tsb_map_vaddr = 0;
|
|
|
|
|
mm->context.tsb_block[tsb_idx].tsb_map_pte = 0;
|
2006-02-02 06:55:21 +07:00
|
|
|
} else {
|
|
|
|
|
tsb_reg |= base;
|
|
|
|
|
tsb_reg |= (tsb_paddr & (page_sz - 1UL));
|
|
|
|
|
tte |= (tsb_paddr & ~(page_sz - 1UL));
|
|
|
|
|
|
2006-03-22 15:49:59 +07:00
|
|
|
mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
|
|
|
|
|
mm->context.tsb_block[tsb_idx].tsb_map_vaddr = base;
|
|
|
|
|
mm->context.tsb_block[tsb_idx].tsb_map_pte = tte;
|
2006-02-02 06:55:21 +07:00
|
|
|
}
|
2006-02-01 09:31:20 +07:00
|
|
|
|
2006-02-10 08:21:53 +07:00
|
|
|
/* Setup the Hypervisor TSB descriptor. */
|
|
|
|
|
if (tlb_type == hypervisor) {
|
2006-03-22 15:49:59 +07:00
|
|
|
struct hv_tsb_descr *hp = &mm->context.tsb_descr[tsb_idx];
|
2006-02-10 08:21:53 +07:00
|
|
|
|
2006-03-22 15:49:59 +07:00
|
|
|
switch (tsb_idx) {
|
|
|
|
|
case MM_TSB_BASE:
|
|
|
|
|
hp->pgsz_idx = HV_PGSZ_IDX_BASE;
|
2006-02-10 08:21:53 +07:00
|
|
|
break;
|
2012-10-09 06:34:29 +07:00
|
|
|
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
|
2006-03-22 15:49:59 +07:00
|
|
|
case MM_TSB_HUGE:
|
|
|
|
|
hp->pgsz_idx = HV_PGSZ_IDX_HUGE;
|
2006-02-10 08:21:53 +07:00
|
|
|
break;
|
2006-03-22 15:49:59 +07:00
|
|
|
#endif
|
|
|
|
|
default:
|
|
|
|
|
BUG();
|
2011-06-03 21:45:23 +07:00
|
|
|
}
|
2006-02-10 08:21:53 +07:00
|
|
|
hp->assoc = 1;
|
|
|
|
|
hp->num_ttes = tsb_bytes / 16;
|
|
|
|
|
hp->ctx_idx = 0;
|
2006-03-22 15:49:59 +07:00
|
|
|
switch (tsb_idx) {
|
|
|
|
|
case MM_TSB_BASE:
|
|
|
|
|
hp->pgsz_mask = HV_PGSZ_MASK_BASE;
|
2006-02-10 08:21:53 +07:00
|
|
|
break;
|
2012-10-09 06:34:29 +07:00
|
|
|
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
|
2006-03-22 15:49:59 +07:00
|
|
|
case MM_TSB_HUGE:
|
|
|
|
|
hp->pgsz_mask = HV_PGSZ_MASK_HUGE;
|
2006-02-10 08:21:53 +07:00
|
|
|
break;
|
2006-03-22 15:49:59 +07:00
|
|
|
#endif
|
|
|
|
|
default:
|
|
|
|
|
BUG();
|
2011-06-03 21:45:23 +07:00
|
|
|
}
|
2006-02-10 08:21:53 +07:00
|
|
|
hp->tsb_base = tsb_paddr;
|
|
|
|
|
hp->resv = 0;
|
|
|
|
|
}
|
2006-02-01 09:31:20 +07:00
|
|
|
}
|
|
|
|
|
|
2011-07-26 07:12:20 +07:00
|
|
|
struct kmem_cache *pgtable_cache __read_mostly;
|
|
|
|
|
|
2006-12-07 11:33:20 +07:00
|
|
|
static struct kmem_cache *tsb_caches[8] __read_mostly;
|
2006-03-19 09:12:42 +07:00
|
|
|
|
|
|
|
|
static const char *tsb_cache_names[8] = {
|
|
|
|
|
"tsb_8KB",
|
|
|
|
|
"tsb_16KB",
|
|
|
|
|
"tsb_32KB",
|
|
|
|
|
"tsb_64KB",
|
|
|
|
|
"tsb_128KB",
|
|
|
|
|
"tsb_256KB",
|
|
|
|
|
"tsb_512KB",
|
|
|
|
|
"tsb_1MB",
|
|
|
|
|
};
|
|
|
|
|
|
2007-05-07 04:49:51 +07:00
|
|
|
void __init pgtable_cache_init(void)
|
2006-03-19 09:12:42 +07:00
|
|
|
{
|
|
|
|
|
unsigned long i;
|
|
|
|
|
|
2011-07-26 07:12:20 +07:00
|
|
|
pgtable_cache = kmem_cache_create("pgtable_cache",
|
|
|
|
|
PAGE_SIZE, PAGE_SIZE,
|
|
|
|
|
0,
|
|
|
|
|
_clear_page);
|
|
|
|
|
if (!pgtable_cache) {
|
|
|
|
|
prom_printf("pgtable_cache_init(): Could not create!\n");
|
|
|
|
|
prom_halt();
|
|
|
|
|
}
|
|
|
|
|
|
2014-03-07 17:59:03 +07:00
|
|
|
for (i = 0; i < ARRAY_SIZE(tsb_cache_names); i++) {
|
2006-03-19 09:12:42 +07:00
|
|
|
unsigned long size = 8192 << i;
|
|
|
|
|
const char *name = tsb_cache_names[i];
|
|
|
|
|
|
|
|
|
|
tsb_caches[i] = kmem_cache_create(name,
|
|
|
|
|
size, size,
|
2007-07-20 08:11:58 +07:00
|
|
|
0, NULL);
|
2006-03-19 09:12:42 +07:00
|
|
|
if (!tsb_caches[i]) {
|
|
|
|
|
prom_printf("Could not create %s cache\n", name);
|
|
|
|
|
prom_halt();
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2008-11-17 14:49:24 +07:00
|
|
|
int sysctl_tsb_ratio = -2;
|
|
|
|
|
|
|
|
|
|
static unsigned long tsb_size_to_rss_limit(unsigned long new_size)
|
|
|
|
|
{
|
|
|
|
|
unsigned long num_ents = (new_size / sizeof(struct tsb));
|
|
|
|
|
|
|
|
|
|
if (sysctl_tsb_ratio < 0)
|
|
|
|
|
return num_ents - (num_ents >> -sysctl_tsb_ratio);
|
|
|
|
|
else
|
|
|
|
|
return num_ents + (num_ents >> sysctl_tsb_ratio);
|
|
|
|
|
}
|
|
|
|
|
|
2006-03-22 15:49:59 +07:00
|
|
|
/* When the RSS of an address space exceeds tsb_rss_limit for a TSB,
|
|
|
|
|
* do_sparc64_fault() invokes this routine to try and grow it.
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
*
|
2006-02-01 09:31:38 +07:00
|
|
|
* When we reach the maximum TSB size supported, we stick ~0UL into
|
2006-03-22 15:49:59 +07:00
|
|
|
* tsb_rss_limit for that TSB so the grow checks in do_sparc64_fault()
|
2006-02-01 09:31:38 +07:00
|
|
|
* will not trigger any longer.
|
|
|
|
|
*
|
|
|
|
|
* The TSB can be anywhere from 8K to 1MB in size, in increasing powers
|
|
|
|
|
* of two. The TSB must be aligned to it's size, so f.e. a 512K TSB
|
2006-03-18 14:40:47 +07:00
|
|
|
* must be 512K aligned. It also must be physically contiguous, so we
|
|
|
|
|
* cannot use vmalloc().
|
2006-02-01 09:31:38 +07:00
|
|
|
*
|
|
|
|
|
* The idea here is to grow the TSB when the RSS of the process approaches
|
|
|
|
|
* the number of entries that the current TSB can hold at once. Currently,
|
|
|
|
|
* we trigger when the RSS hits 3/4 of the TSB capacity.
|
|
|
|
|
*/
|
2006-03-22 15:49:59 +07:00
|
|
|
void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
|
2006-02-01 09:31:38 +07:00
|
|
|
{
|
|
|
|
|
unsigned long max_tsb_size = 1 * 1024 * 1024;
|
2006-03-19 09:12:42 +07:00
|
|
|
unsigned long new_size, old_size, flags;
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
struct tsb *old_tsb, *new_tsb;
|
2006-03-19 09:12:42 +07:00
|
|
|
unsigned long new_cache_index, old_cache_index;
|
|
|
|
|
unsigned long new_rss_limit;
|
2006-03-18 14:40:47 +07:00
|
|
|
gfp_t gfp_flags;
|
2006-02-01 09:31:38 +07:00
|
|
|
|
|
|
|
|
if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
|
|
|
|
|
max_tsb_size = (PAGE_SIZE << MAX_ORDER);
|
|
|
|
|
|
2006-03-19 09:12:42 +07:00
|
|
|
new_cache_index = 0;
|
|
|
|
|
for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
|
2008-11-17 14:49:24 +07:00
|
|
|
new_rss_limit = tsb_size_to_rss_limit(new_size);
|
|
|
|
|
if (new_rss_limit > rss)
|
2006-02-01 09:31:38 +07:00
|
|
|
break;
|
2006-03-19 09:12:42 +07:00
|
|
|
new_cache_index++;
|
2006-02-01 09:31:38 +07:00
|
|
|
}
|
|
|
|
|
|
2006-03-19 09:12:42 +07:00
|
|
|
if (new_size == max_tsb_size)
|
2006-03-18 14:40:47 +07:00
|
|
|
new_rss_limit = ~0UL;
|
|
|
|
|
|
2006-03-19 09:12:42 +07:00
|
|
|
retry_tsb_alloc:
|
2006-03-18 14:40:47 +07:00
|
|
|
gfp_flags = GFP_KERNEL;
|
2006-03-19 09:12:42 +07:00
|
|
|
if (new_size > (PAGE_SIZE * 2))
|
2013-02-20 03:56:18 +07:00
|
|
|
gfp_flags |= __GFP_NOWARN | __GFP_NORETRY;
|
2006-03-18 14:40:47 +07:00
|
|
|
|
2008-03-19 18:53:58 +07:00
|
|
|
new_tsb = kmem_cache_alloc_node(tsb_caches[new_cache_index],
|
|
|
|
|
gfp_flags, numa_node_id());
|
2006-03-19 09:12:42 +07:00
|
|
|
if (unlikely(!new_tsb)) {
|
2006-03-18 14:40:47 +07:00
|
|
|
/* Not being able to fork due to a high-order TSB
|
|
|
|
|
* allocation failure is very bad behavior. Just back
|
|
|
|
|
* down to a 0-order allocation and force no TSB
|
|
|
|
|
* growing for this address space.
|
|
|
|
|
*/
|
2006-03-22 15:49:59 +07:00
|
|
|
if (mm->context.tsb_block[tsb_index].tsb == NULL &&
|
|
|
|
|
new_cache_index > 0) {
|
2006-03-19 09:12:42 +07:00
|
|
|
new_cache_index = 0;
|
|
|
|
|
new_size = 8192;
|
2006-03-18 14:40:47 +07:00
|
|
|
new_rss_limit = ~0UL;
|
2006-03-19 09:12:42 +07:00
|
|
|
goto retry_tsb_alloc;
|
2006-03-18 14:40:47 +07:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* If we failed on a TSB grow, we are under serious
|
|
|
|
|
* memory pressure so don't try to grow any more.
|
|
|
|
|
*/
|
2006-03-22 15:49:59 +07:00
|
|
|
if (mm->context.tsb_block[tsb_index].tsb != NULL)
|
|
|
|
|
mm->context.tsb_block[tsb_index].tsb_rss_limit = ~0UL;
|
2006-02-01 09:31:38 +07:00
|
|
|
return;
|
2006-03-18 14:40:47 +07:00
|
|
|
}
|
2006-02-01 09:31:38 +07:00
|
|
|
|
2006-02-18 09:01:02 +07:00
|
|
|
/* Mark all tags as invalid. */
|
2006-03-19 14:55:11 +07:00
|
|
|
tsb_init(new_tsb, new_size);
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
|
|
|
|
|
/* Ok, we are about to commit the changes. If we are
|
|
|
|
|
* growing an existing TSB the locking is very tricky,
|
|
|
|
|
* so WATCH OUT!
|
|
|
|
|
*
|
|
|
|
|
* We have to hold mm->context.lock while committing to the
|
|
|
|
|
* new TSB, this synchronizes us with processors in
|
|
|
|
|
* flush_tsb_user() and switch_mm() for this address space.
|
|
|
|
|
*
|
|
|
|
|
* But even with that lock held, processors run asynchronously
|
|
|
|
|
* accessing the old TSB via TLB miss handling. This is OK
|
|
|
|
|
* because those actions are just propagating state from the
|
|
|
|
|
* Linux page tables into the TSB, page table mappings are not
|
|
|
|
|
* being changed. If a real fault occurs, the processor will
|
|
|
|
|
* synchronize with us when it hits flush_tsb_user(), this is
|
|
|
|
|
* also true for the case where vmscan is modifying the page
|
|
|
|
|
* tables. The only thing we need to be careful with is to
|
|
|
|
|
* skip any locked TSB entries during copy_tsb().
|
|
|
|
|
*
|
|
|
|
|
* When we finish committing to the new TSB, we have to drop
|
|
|
|
|
* the lock and ask all other cpus running this address space
|
|
|
|
|
* to run tsb_context_switch() to see the new TSB table.
|
|
|
|
|
*/
|
|
|
|
|
spin_lock_irqsave(&mm->context.lock, flags);
|
|
|
|
|
|
2006-03-22 15:49:59 +07:00
|
|
|
old_tsb = mm->context.tsb_block[tsb_index].tsb;
|
|
|
|
|
old_cache_index =
|
|
|
|
|
(mm->context.tsb_block[tsb_index].tsb_reg_val & 0x7UL);
|
|
|
|
|
old_size = (mm->context.tsb_block[tsb_index].tsb_nentries *
|
|
|
|
|
sizeof(struct tsb));
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
|
2006-03-19 09:12:42 +07:00
|
|
|
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
/* Handle multiple threads trying to grow the TSB at the same time.
|
|
|
|
|
* One will get in here first, and bump the size and the RSS limit.
|
|
|
|
|
* The others will get in here next and hit this check.
|
|
|
|
|
*/
|
2006-03-22 15:49:59 +07:00
|
|
|
if (unlikely(old_tsb &&
|
|
|
|
|
(rss < mm->context.tsb_block[tsb_index].tsb_rss_limit))) {
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
spin_unlock_irqrestore(&mm->context.lock, flags);
|
|
|
|
|
|
2006-03-19 09:12:42 +07:00
|
|
|
kmem_cache_free(tsb_caches[new_cache_index], new_tsb);
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
return;
|
|
|
|
|
}
|
2006-02-18 09:01:02 +07:00
|
|
|
|
2006-03-22 15:49:59 +07:00
|
|
|
mm->context.tsb_block[tsb_index].tsb_rss_limit = new_rss_limit;
|
2006-02-01 09:31:38 +07:00
|
|
|
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
if (old_tsb) {
|
|
|
|
|
extern void copy_tsb(unsigned long old_tsb_base,
|
|
|
|
|
unsigned long old_tsb_size,
|
|
|
|
|
unsigned long new_tsb_base,
|
|
|
|
|
unsigned long new_tsb_size);
|
|
|
|
|
unsigned long old_tsb_base = (unsigned long) old_tsb;
|
|
|
|
|
unsigned long new_tsb_base = (unsigned long) new_tsb;
|
|
|
|
|
|
|
|
|
|
if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
|
|
|
|
|
old_tsb_base = __pa(old_tsb_base);
|
|
|
|
|
new_tsb_base = __pa(new_tsb_base);
|
|
|
|
|
}
|
2006-03-19 09:12:42 +07:00
|
|
|
copy_tsb(old_tsb_base, old_size, new_tsb_base, new_size);
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
}
|
2006-02-01 09:31:38 +07:00
|
|
|
|
2006-03-22 15:49:59 +07:00
|
|
|
mm->context.tsb_block[tsb_index].tsb = new_tsb;
|
|
|
|
|
setup_tsb_params(mm, tsb_index, new_size);
|
2006-02-01 09:31:38 +07:00
|
|
|
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
spin_unlock_irqrestore(&mm->context.lock, flags);
|
|
|
|
|
|
2006-02-01 09:31:38 +07:00
|
|
|
/* If old_tsb is NULL, we're being invoked for the first time
|
|
|
|
|
* from init_new_context().
|
|
|
|
|
*/
|
|
|
|
|
if (old_tsb) {
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
/* Reload it on the local cpu. */
|
2006-02-01 09:31:38 +07:00
|
|
|
tsb_context_switch(mm);
|
|
|
|
|
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
/* Now force other processors to do the same. */
|
2008-08-03 14:01:05 +07:00
|
|
|
preempt_disable();
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
smp_tsb_sync(mm);
|
2008-08-03 14:01:05 +07:00
|
|
|
preempt_enable();
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
|
|
|
|
|
/* Now it is safe to free the old tsb. */
|
2006-03-19 09:12:42 +07:00
|
|
|
kmem_cache_free(tsb_caches[old_cache_index], old_tsb);
|
2006-02-01 09:31:38 +07:00
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2006-02-01 09:31:06 +07:00
|
|
|
int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
|
|
|
|
|
{
|
2016-09-01 03:48:19 +07:00
|
|
|
unsigned long mm_rss = get_mm_rss(mm);
|
2012-10-09 06:34:29 +07:00
|
|
|
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
|
2016-09-01 03:48:19 +07:00
|
|
|
unsigned long saved_hugetlb_pte_count;
|
|
|
|
|
unsigned long saved_thp_pte_count;
|
2006-03-22 15:49:59 +07:00
|
|
|
#endif
|
|
|
|
|
unsigned int i;
|
|
|
|
|
|
2006-03-07 10:59:50 +07:00
|
|
|
spin_lock_init(&mm->context.lock);
|
2006-02-01 09:31:06 +07:00
|
|
|
|
|
|
|
|
mm->context.sparc64_ctx_val = 0UL;
|
|
|
|
|
|
2012-10-09 06:34:29 +07:00
|
|
|
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
|
2016-07-16 03:08:42 +07:00
|
|
|
/* We reset them to zero because the fork() page copying
|
2006-03-22 15:49:59 +07:00
|
|
|
* will re-increment the counters as the parent PTEs are
|
|
|
|
|
* copied into the child address space.
|
|
|
|
|
*/
|
2016-09-01 03:48:19 +07:00
|
|
|
saved_hugetlb_pte_count = mm->context.hugetlb_pte_count;
|
|
|
|
|
saved_thp_pte_count = mm->context.thp_pte_count;
|
2016-07-16 03:08:42 +07:00
|
|
|
mm->context.hugetlb_pte_count = 0;
|
|
|
|
|
mm->context.thp_pte_count = 0;
|
2016-09-01 03:48:19 +07:00
|
|
|
|
|
|
|
|
mm_rss -= saved_thp_pte_count * (HPAGE_SIZE / PAGE_SIZE);
|
2006-03-22 15:49:59 +07:00
|
|
|
#endif
|
|
|
|
|
|
2006-02-01 09:31:38 +07:00
|
|
|
/* copy_mm() copies over the parent's mm_struct before calling
|
|
|
|
|
* us, so we need to zero out the TSB pointer or else tsb_grow()
|
|
|
|
|
* will be confused and think there is an older TSB to free up.
|
|
|
|
|
*/
|
2006-03-22 15:49:59 +07:00
|
|
|
for (i = 0; i < MM_NUM_TSBS; i++)
|
|
|
|
|
mm->context.tsb_block[i].tsb = NULL;
|
[SPARC64]: Fix and re-enable dynamic TSB sizing.
This is good for up to %50 performance improvement of some test cases.
The problem has been the race conditions, and hopefully I've plugged
them all up here.
1) There was a serious race in switch_mm() wrt. lazy TLB
switching to and from kernel threads.
We could erroneously skip a tsb_context_switch() and thus
use a stale TSB across a TSB grow event.
There is a big comment now in that function describing
exactly how it can happen.
2) All code paths that do something with the TSB need to be
guarded with the mm->context.lock spinlock. This makes
page table flushing paths properly synchronize with both
TSB growing and TLB context changes.
3) TSB growing events are moved to the end of successful fault
processing. Previously it was in update_mmu_cache() but
that is deadlock prone. At the end of do_sparc64_fault()
we hold no spinlocks that could deadlock the TSB grow
sequence. We also have dropped the address space semaphore.
While we're here, add prefetching to the copy_tsb() routine
and put it in assembler into the tsb.S file. This piece of
code is quite time critical.
There are some small negative side effects to this code which
can be improved upon. In particular we grab the mm->context.lock
even for the tsb insert done by update_mmu_cache() now and that's
a bit excessive. We can get rid of that locking, and the same
lock taking in flush_tsb_user(), by disabling PSTATE_IE around
the whole operation including the capturing of the tsb pointer
and tsb_nentries value. That would work because anyone growing
the TSB won't free up the old TSB until all cpus respond to the
TSB change cross call.
I'm not quite so confident in that optimization to put it in
right now, but eventually we might be able to and the description
is here for reference.
This code seems very solid now. It passes several parallel GCC
bootstrap builds, and our favorite "nut cruncher" stress test which is
a full "make -j8192" build of a "make allmodconfig" kernel. That puts
about 256 processes on each cpu's run queue, makes lots of process cpu
migrations occur, causes lots of page table and TLB flushing activity,
incurs many context version number changes, and it swaps the machine
real far out to disk even though there is 16GB of ram on this test
system. :-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-16 17:02:32 +07:00
|
|
|
|
|
|
|
|
/* If this is fork, inherit the parent's TSB size. We would
|
|
|
|
|
* grow it to that size on the first page fault anyways.
|
|
|
|
|
*/
|
2016-09-01 03:48:19 +07:00
|
|
|
tsb_grow(mm, MM_TSB_BASE, mm_rss);
|
2006-02-01 09:31:38 +07:00
|
|
|
|
2012-10-09 06:34:29 +07:00
|
|
|
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
|
2016-09-01 03:48:19 +07:00
|
|
|
if (unlikely(saved_hugetlb_pte_count + saved_thp_pte_count))
|
|
|
|
|
tsb_grow(mm, MM_TSB_HUGE,
|
|
|
|
|
(saved_hugetlb_pte_count + saved_thp_pte_count) *
|
|
|
|
|
REAL_HPAGE_PER_HPAGE);
|
2006-03-22 15:49:59 +07:00
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
if (unlikely(!mm->context.tsb_block[MM_TSB_BASE].tsb))
|
2006-02-01 09:31:38 +07:00
|
|
|
return -ENOMEM;
|
2006-02-01 09:31:06 +07:00
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
2006-03-22 15:49:59 +07:00
|
|
|
static void tsb_destroy_one(struct tsb_config *tp)
|
2006-02-01 09:31:06 +07:00
|
|
|
{
|
2006-03-22 15:49:59 +07:00
|
|
|
unsigned long cache_index;
|
2006-02-01 09:31:38 +07:00
|
|
|
|
2006-03-22 15:49:59 +07:00
|
|
|
if (!tp->tsb)
|
|
|
|
|
return;
|
|
|
|
|
cache_index = tp->tsb_reg_val & 0x7UL;
|
|
|
|
|
kmem_cache_free(tsb_caches[cache_index], tp->tsb);
|
|
|
|
|
tp->tsb = NULL;
|
|
|
|
|
tp->tsb_reg_val = 0UL;
|
|
|
|
|
}
|
2006-02-01 09:31:20 +07:00
|
|
|
|
2006-03-22 15:49:59 +07:00
|
|
|
void destroy_context(struct mm_struct *mm)
|
|
|
|
|
{
|
|
|
|
|
unsigned long flags, i;
|
|
|
|
|
|
|
|
|
|
for (i = 0; i < MM_NUM_TSBS; i++)
|
|
|
|
|
tsb_destroy_one(&mm->context.tsb_block[i]);
|
2006-02-01 09:31:06 +07:00
|
|
|
|
2006-02-24 12:40:15 +07:00
|
|
|
spin_lock_irqsave(&ctx_alloc_lock, flags);
|
2006-02-01 09:31:06 +07:00
|
|
|
|
|
|
|
|
if (CTX_VALID(mm->context)) {
|
|
|
|
|
unsigned long nr = CTX_NRBITS(mm->context);
|
|
|
|
|
mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63));
|
|
|
|
|
}
|
|
|
|
|
|
2006-02-24 12:40:15 +07:00
|
|
|
spin_unlock_irqrestore(&ctx_alloc_lock, flags);
|
2006-02-01 09:31:06 +07:00
|
|
|
}
|