KM_USER1 is never used for vwrite() path so the caller doesn't need to
guarantee it is not used. Only the caller should guarantee is KM_USER0
and it is commented already.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For range-cyclic writeback (e.g. kupdate), the writeback code sets a
continuation point of the next writeback to mapping->writeback_index which
is set the page after the last written page. This happens so that we
evenly write the whole file even if pages in it get continuously
redirtied.
However, in some cases, sequential writer is writing in the middle of the
page and it just redirties the last written page by continuing from that.
For example with an application which uses a file as a big ring buffer we
see:
[1st writeback session]
...
flush-8:0-2743 4571: block_bio_queue: 8,0 W 94898514 + 8
flush-8:0-2743 4571: block_bio_queue: 8,0 W 94898522 + 8
flush-8:0-2743 4571: block_bio_queue: 8,0 W 94898530 + 8
flush-8:0-2743 4571: block_bio_queue: 8,0 W 94898538 + 8
flush-8:0-2743 4571: block_bio_queue: 8,0 W 94898546 + 8
kworker/0:1-11 4571: block_rq_issue: 8,0 W 0 () 94898514 + 40
>> flush-8:0-2743 4571: block_bio_queue: 8,0 W 94898554 + 8
>> flush-8:0-2743 4571: block_rq_issue: 8,0 W 0 () 94898554 + 8
[2nd writeback session after 35sec]
flush-8:0-2743 4606: block_bio_queue: 8,0 W 94898562 + 8
flush-8:0-2743 4606: block_bio_queue: 8,0 W 94898570 + 8
flush-8:0-2743 4606: block_bio_queue: 8,0 W 94898578 + 8
...
kworker/0:1-11 4606: block_rq_issue: 8,0 W 0 () 94898562 + 640
kworker/0:1-11 4606: block_rq_issue: 8,0 W 0 () 94899202 + 72
...
flush-8:0-2743 4606: block_bio_queue: 8,0 W 94899962 + 8
flush-8:0-2743 4606: block_bio_queue: 8,0 W 94899970 + 8
flush-8:0-2743 4606: block_bio_queue: 8,0 W 94899978 + 8
flush-8:0-2743 4606: block_bio_queue: 8,0 W 94899986 + 8
flush-8:0-2743 4606: block_bio_queue: 8,0 W 94899994 + 8
kworker/0:1-11 4606: block_rq_issue: 8,0 W 0 () 94899962 + 40
>> flush-8:0-2743 4606: block_bio_queue: 8,0 W 94898554 + 8
>> flush-8:0-2743 4606: block_rq_issue: 8,0 W 0 () 94898554 + 8
So we seeked back to 94898554 after we wrote all the pages at the end of
the file.
This extra seek seems unnecessary. If we continue writeback from the last
written page, we can avoid it and do not cause harm to other cases. The
original intent of even writeout over the whole file is preserved and if
the page does not get redirtied pagevec_lookup_tag() just skips it.
As an exceptional case, when I/O error happens, set done_index to the next
page as the comment in the code suggests.
Tested-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
scan_swap_map() is a large function (224 lines), with several loops and a
complex control flow involving several gotos.
Given all that, it is a bit silly that it is marked as inline. The
compiler agrees with me: on a x86-64 compile, it did not inline the
function.
Remove the "inline" and let the compiler decide instead.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The block in sys_swapon which does the final adjustments to the
swap_info_struct and to swap_list is the same as the block which
re-inserts it again at sys_swapoff on failure of try_to_unuse(). Move
this code to a separate function, and use it both in sys_swapon and
sys_swapoff.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The block in sys_swapon which does the final adjustments to the
swap_info_struct and to swap_list is the same as the block which
re-inserts it again at sys_swapoff on failure of try_to_unuse(), except
for the order of the operations within the lock. Since the order should
not matter, arbitrarily change sys_swapoff to match sys_swapon, in
preparation to making both share the same code.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The block in sys_swapon which does the final adjustments to the
swap_info_struct and to swap_list is the same as the block which
re-inserts it again at sys_swapoff on failure of try_to_unuse(). To be
able to make both share the same code, move the printk() call in the
middle of it to just after it.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It still exists within setup_swap_map_and_extents(), but after it
nr_good_pages == p->pages.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since there is no cleanup to do, there is no reason to jump to a label.
Return directly instead.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the code which parses the bad block list and the extents to a
separate function. Only code movement, no functional changes.
This change uses the fact that, after the success path, nr_good_pages ==
p->pages.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The call to swap_cgroup_swapon is in the middle of loading the swap map
and extents. As it only does memory allocation and does not depend on
the swapfile layout (map/extents), it can be called earlier (or later).
Move it to just after the allocation of swap_map, since it is
conceptually similar (allocates a map).
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since there is no cleanup to do, there is no reason to jump to a label.
Return directly instead.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the code which parses and checks the swapfile header (except for
the bad block list) to a separate function. Only code movement, no
functional changes.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is no reason I can see to read inode->i_size long before it is
needed. Move its read to just before it is needed, to reduce the
variable lifetime.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Jesper Juhl <jj@chaosbits.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since there is no cleanup to do, there is no reason to jump to a label.
Return directly instead.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the code which claims the bdev (S_ISBLK) or locks the inode
(S_ISREG) to a separate function. Only code movement, no functional
changes.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sys_swapon currently has two error labels, bad_swap and bad_swap_2.
bad_swap does the same as bad_swap_2 plus destroy_swap_extents() and
swap_cgroup_swapoff(); both are noops in the places where bad_swap_2 is
jumped to. With a single extra test for inode (matching the one in the
S_ISREG case below), all the error paths in the function can go to
bad_swap.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The only way error is 0 in the cleanup blocks is when the function is
returning successfully. In this case, the cleanup blocks were setting
S_SWAPFILE in the S_ISREG case. But this is not a cleanup.
Move the setting of S_SWAPFILE to just before the "goto out;" to make
this more clear. At this point, we do not need to test for inode because
it will never be NULL.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The bdev variable is always equivalent to (S_ISBLK(inode->i_mode) ?
p->bdev : NULL), as long as it being set is moved to a bit earlier. Use
this fact to remove the bdev variable.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the setting of the error variable nearer the goto in a few places.
Avoids calling PTR_ERR() if not IS_ERR() in two places, and makes the
error condition more explicit in two other places.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Jesper Juhl <jj@chaosbits.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since mutex_lock(&inode->i_mutex) is called just after setting inode,
did_down is always equivalent to (inode && S_ISREG(inode->i_mode)).
Use this fact to remove the did_down variable.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now there is nothing which jumps to the cleanup blocks before the name
variable is set. There is no need to set it initially to NULL anymore.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since there is no cleanup to do, there is no reason to jump to a label.
Return directly instead.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
At this point in sys_swapon, there is nothing to free. Return directly
instead of jumping to the cleanup block at the end of the function.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the swap_info allocation to its own function. Only code movement,
no functional changes.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Within sys_swapon, after the swap_info entry has been allocated, we
always have type == p->type and swap_info[type] == p. Use this fact to
reduce the dependency on the "type" local variable within the function,
as a preparation to move the allocation of the swap_info entry to a
separate function.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujisu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Changelogs belong in the git history instead of in the source code.
Also, "The swapon system call" is redundant with
"SYSCALL_DEFINE2(swapon, ...)".
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: Jesper Juhl <jj@chaosbits.net>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ Gaah. That's a _historical_ comment. But the patch-series depends on removal ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch series refactors the sys_swapon function.
sys_swapon is currently a very large function, with 313 lines (more than
12 25-line screens), which can make it a bit hard to read. This patch
series reduces this size by half, by extracting large chunks of related
code to new helper functions.
One of these chunks of code was nearly identical to the part of
sys_swapoff which is used in case of a failure return from
try_to_unuse(), so this patch series also makes both share the same
code.
As a side effect of all this refactoring, the compiled code gets a bit
smaller (from v1 of this patch series):
text data bss dec hex filename
14012 944 276 15232 3b80 mm/swapfile.o.before
13941 944 276 15161 3b39 mm/swapfile.o.after
This patch:
Use vzalloc() instead of vmalloc/memset.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: Jesper Juhl <jj@chaosbits.net>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pass __GFP_OTHER_NODE for transparent hugepages NUMA allocations done by the
hugepages daemon. This way the low level accounting for local versus
remote pages works correctly.
Contains improvements from Andrea Arcangeli
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a new __GFP_OTHER_NODE flag to tell the low level numa statistics in
zone_statistics() that an allocation is on behalf of another thread. This
way the local and remote counters can be still correct, even when
background daemons like khugepaged are changing memory mappings.
This only affects the accounting, but I think it's worth doing that right
to avoid confusing users.
I first tried to just pass down the right node, but this required a lot of
changes to pass down this parameter and at least one addition of a 10th
argument to a 9 argument function. Using the flag is a lot less
intrusive.
Open: should be also used for migration?
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__GFP_NO_KSWAPD allocations are usually very expensive and not mandatory
to succeed as they have graceful fallback. Waiting for I/O in those,
tends to be overkill in terms of latencies, so we can reduce their latency
by disabling sync migrate.
Unfortunately, even with async migration it's still possible for the
process to be blocked waiting for a request slot (e.g. get_request_wait
in the block layer) when ->writepage is called. To prevent
__GFP_NO_KSWAPD blocking, this patch prevents ->writepage being called on
dirty page cache for asynchronous migration.
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=31142
[mel@csn.ul.ie: Avoid writebacks for NFS, retry locked pages, use bool]
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Arthur Marsh <arthur.marsh@internode.on.net>
Cc: Clemens Ladisch <cladisch@googlemail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Reported-by: Alex Villacis Lasso <avillaci@ceibo.fiec.espol.edu.ec>
Tested-by: Alex Villacis Lasso <avillaci@ceibo.fiec.espol.edu.ec>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
compaction_alloc() isolates pages for migration in isolate_migratepages.
While it's scanning, IRQs are disabled on the mistaken assumption the
scanning should be short. Tests show this to be true for the most part
but contention times on the LRU lock can be increased. Before this patch,
the IRQ disabled times for a simple test looked like
Total sampled time IRQs off (not real total time): 5493
Event shrink_inactive_list..shrink_zone 1596 us count 1
Event shrink_inactive_list..shrink_zone 1530 us count 1
Event shrink_inactive_list..shrink_zone 956 us count 1
Event shrink_inactive_list..shrink_zone 541 us count 1
Event shrink_inactive_list..shrink_zone 531 us count 1
Event split_huge_page..add_to_swap 232 us count 1
Event save_args..call_softirq 36 us count 1
Event save_args..call_softirq 35 us count 2
Event __wake_up..__wake_up 1 us count 1
This patch reduces the worst-case IRQs-disabled latencies by releasing the
lock every SWAP_CLUSTER_MAX pages that are scanned and releasing the CPU if
necessary. The cost of this is that the processing performing compaction will
be slower but IRQs being disabled for too long a time has worse consequences
as the following report shows;
Total sampled time IRQs off (not real total time): 4367
Event shrink_inactive_list..shrink_zone 881 us count 1
Event shrink_inactive_list..shrink_zone 875 us count 1
Event shrink_inactive_list..shrink_zone 868 us count 1
Event shrink_inactive_list..shrink_zone 555 us count 1
Event split_huge_page..add_to_swap 495 us count 1
Event compact_zone..compact_zone_order 269 us count 1
Event split_huge_page..add_to_swap 266 us count 1
Event shrink_inactive_list..shrink_zone 85 us count 1
Event save_args..call_softirq 36 us count 2
Event __wake_up..__wake_up 1 us count 1
[akpm@linux-foundation.org: simplify with s/unlocked/locked/]
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Arthur Marsh <arthur.marsh@internode.on.net>
Cc: Clemens Ladisch <cladisch@googlemail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
compaction_alloc() isolates free pages to be used as migration targets.
While its scanning, IRQs are disabled on the mistaken assumption the
scanning should be short. Analysis showed that IRQs were in fact being
disabled for substantial time. A simple test was run using large
anonymous mappings with transparent hugepage support enabled to trigger
frequent compactions. A monitor sampled what the worst IRQ-off latencies
were and a post-processing tool found the following;
Total sampled time IRQs off (not real total time): 22355
Event compaction_alloc..compaction_alloc 8409 us count 1
Event compaction_alloc..compaction_alloc 7341 us count 1
Event compaction_alloc..compaction_alloc 2463 us count 1
Event compaction_alloc..compaction_alloc 2054 us count 1
Event shrink_inactive_list..shrink_zone 1864 us count 1
Event shrink_inactive_list..shrink_zone 88 us count 1
Event save_args..call_softirq 36 us count 1
Event save_args..call_softirq 35 us count 2
Event __make_request..__blk_run_queue 24 us count 1
Event __alloc_pages_nodemask..__alloc_pages_nodemask 6 us count 1
i.e. compaction is disabled IRQs for a prolonged period of time - 8ms in
one instance. The full report generated by the tool can be found at
http://www.csn.ul.ie/~mel/postings/minfree-20110225/irqsoff-vanilla-micro.report
This patch reduces the time IRQs are disabled by simply disabling IRQs at
the last possible minute. An updated IRQs-off summary report then looks
like;
Total sampled time IRQs off (not real total time): 5493
Event shrink_inactive_list..shrink_zone 1596 us count 1
Event shrink_inactive_list..shrink_zone 1530 us count 1
Event shrink_inactive_list..shrink_zone 956 us count 1
Event shrink_inactive_list..shrink_zone 541 us count 1
Event shrink_inactive_list..shrink_zone 531 us count 1
Event split_huge_page..add_to_swap 232 us count 1
Event save_args..call_softirq 36 us count 1
Event save_args..call_softirq 35 us count 2
Event __wake_up..__wake_up 1 us count 1
A full report is again available at
http://www.csn.ul.ie/~mel/postings/minfree-20110225/irqsoff-minimiseirq-free-v1r4-micro.report
As should be obvious, IRQ disabled latencies due to compaction are
almost elimimnated for this particular test.
[aarcange@redhat.com: Fix initialisation of isolated]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujisu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Arthur Marsh <arthur.marsh@internode.on.net>
Cc: Clemens Ladisch <cladisch@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Callers of find_get_pages(), or its wrapper pagevec_lookup() - notably
truncate_inode_pages_range() - stop looking further when it returns 0.
But if an interrupt comes just after its radix_tree_gang_lookup_slot(),
especially if we have preemptible RCU enabled, isn't it conceivable that
all 14 pages returned could be removed from the page cache by
shrink_page_list(), before find_get_pages() gets to process them? So
causing it to return 0 although there may be plenty more pages beyond.
Make find_get_pages() and find_get_pages_tag() check for this unlikely
case, and restart should it occur; but callers of find_get_pages_contig()
have no such expectation, it's okay for that to return 0 early.
I have not seen this in practice, just worried by the possibility.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Salman Qazi <sqazi@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The radix_tree_deref_retry() case in find_get_pages() has a strange little
excrescence, not seen in the other gang lookups: it looks like the start
of an abandoned attempt to guarantee forward progress in a case that
cannot arise.
ret should always be 0 here: if it isn't, then going back to restart will
leak references to pages already gotten. There used to be a comment
saying nr_found is necessarily 1 here: that's not quite true, but the
radix_tree_deref_retry() case is peculiar to the entry at index 0, when we
race with it being moved out of the radix_tree root or back.
Remove the worrisome two lines, add a brief comment here and in
find_get_pages_contig() and find_get_pages_tag(), and a WARN_ON in
find_get_pages() should it ever be seen elsewhere than at 0.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Salman Qazi <sqazi@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the user inserts a negative value into /proc/sys/vm/nr_hugepages it
will cause the kernel to allocate as many hugepages as possible and to
then update /proc/meminfo to reflect this.
This changes the behavior so that the negative input will result in
nr_hugepages value being unchanged.
Signed-off-by: Petr Holasek <pholasek@redhat.com>
Signed-off-by: Anton Arapov <anton@redhat.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Eric B Munson <emunson@mgebm.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When reclaiming for order-0 pages, kswapd requires that all zones be
balanced. Each cycle through balance_pgdat() does background ageing on
all zones if necessary and applies equal pressure on the inactive zone
unless a lot of pages are free already.
A "lot of free pages" is defined as a "balance gap" above the high
watermark which is currently 7*high_watermark. Historically this was
reasonable as min_free_kbytes was small. However, on systems using huge
pages, it is recommended that min_free_kbytes is higher and it is tuned
with hugeadm --set-recommended-min_free_kbytes. With the introduction of
transparent huge page support, this recommended value is also applied. On
X86-64 with 4G of memory, min_free_kbytes becomes 67584 so one would
expect around 68M of memory to be free. The Normal zone is approximately
35000 pages so under even normal memory pressure such as copying a large
file, it gets exhausted quickly. As it is getting exhausted, kswapd
applies pressure equally to all zones, including the DMA32 zone. DMA32 is
approximately 700,000 pages with a high watermark of around 23,000 pages.
In this situation, kswapd will reclaim around (23000*8 where 8 is the high
watermark + balance gap of 7 * high watermark) pages or 718M of pages
before the zone is ignored. What the user sees is that free memory far
higher than it should be.
To avoid an excessive number of pages being reclaimed from the larger
zones, explicitely defines the "balance gap" to be either 1% of the zone
or the low watermark for the zone, whichever is smaller. While kswapd
will check all zones to apply pressure, it'll ignore zones that meets the
(high_wmark + balance_gap) watermark.
To test this, 80G were copied from a partition and the amount of memory
being used was recorded. A comparison of a patch and unpatched kernel can
be seen at
http://www.csn.ul.ie/~mel/postings/minfree-20110222/memory-usage-hydra.ps
and shows that kswapd is not reclaiming as much memory with the patch
applied.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: "Chen, Tim C" <tim.c.chen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The 'flags' field is already checked, no need to do it again.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: Bob Liu <lliubbo@gmail.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Right now, if a mm_walk has either ->pte_entry or ->pmd_entry set, it will
unconditionally split any transparent huge pages it runs in to. In
practice, that means that anyone doing a
cat /proc/$pid/smaps
will unconditionally break down every huge page in the process and depend
on khugepaged to re-collapse it later. This is fairly suboptimal.
This patch changes that behavior. It teaches each ->pmd_entry handler
(there are five) that they must break down the THPs themselves. Also, the
_generic_ code will never break down a THP unless a ->pte_entry handler is
actually set.
This means that the ->pmd_entry handlers can now choose to deal with THPs
without breaking them down.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Eric B Munson <emunson@mgebm.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Cc: Michael J Wolf <mjwolf@us.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
invalidate_mapping_pages is very big hint to reclaimer. It means user
doesn't want to use the page any more. So in order to prevent working set
page eviction, this patch move the page into tail of inactive list by
PG_reclaim.
Please, remember that pages in inactive list are working set as well as
active list. If we don't move pages into inactive list's tail, pages near
by tail of inactive list can be evicted although we have a big clue about
useless pages. It's totally bad.
Now PG_readahead/PG_reclaim is shared. fe3cba17 added ClearPageReclaim
into clear_page_dirty_for_io for preventing fast reclaiming readahead
marker page.
In this series, PG_reclaim is used by invalidated page, too. If VM find
the page is invalidated and it's dirty, it sets PG_reclaim to reclaim
asap. Then, when the dirty page will be writeback,
clear_page_dirty_for_io will clear PG_reclaim unconditionally. It
disturbs this serie's goal.
I think it's okay to clear PG_readahead when the page is dirty, not
writeback time. So this patch moves ClearPageReadahead. In v4,
ClearPageReadahead in set_page_dirty has a problem which is reported by
Steven Barrett. It's due to compound page. Some driver(ex, audio) calls
set_page_dirty with compound page which isn't on LRU. but my patch does
ClearPageRelcaim on compound page. In non-CONFIG_PAGEFLAGS_EXTENDED, it
breaks PageTail flag.
I think it doesn't affect THP and pass my test with THP enabling but Cced
Andrea for double check.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Reported-by: Steven Barrett <damentz@liquorix.net>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The rotate_reclaimable_page function moves just written out pages, which
the VM wanted to reclaim, to the end of the inactive list. That way the
VM will find those pages first next time it needs to free memory.
This patch applies the rule in memcg. It can help to prevent unnecessary
working page eviction of memcg.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recently, there are reported problem about thrashing.
(http://marc.info/?l=rsync&m=128885034930933&w=2) It happens by backup
workloads(ex, nightly rsync). That's because the workload makes just
use-once pages and touches pages twice. It promotes the page into active
list so that it results in working set page eviction.
Some app developer want to support POSIX_FADV_NOREUSE. But other OSes
don't support it, either.
(http://marc.info/?l=linux-mm&m=128928979512086&w=2)
By other approach, app developers use POSIX_FADV_DONTNEED. But it has a
problem. If kernel meets page is writing during invalidate_mapping_pages,
it can't work. It makes for application programmer to use it since they
always have to sync data before calling fadivse(..POSIX_FADV_DONTNEED) to
make sure the pages could be discardable. At last, they can't use
deferred write of kernel so that they could see performance loss.
(http://insights.oetiker.ch/linux/fadvise.html)
In fact, invalidation is very big hint to reclaimer. It means we don't
use the page any more. So let's move the writing page into inactive
list's head if we can't truncate it right now.
Why I move page to head of lru on this patch, Dirty/Writeback page would
be flushed sooner or later. It can prevent writeout of pageout which is
less effective than flusher's writeout.
Originally, I reused lru_demote of Peter with some change so added his
Signed-off-by.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Reported-by: Ben Gamari <bgamari.foss@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch changes the anon_vma refcount to be 0 when the object is free.
It does this by adding 1 ref to being in use in the anon_vma structure
(iow. the anon_vma->head list is not empty).
This allows a simpler release scheme without having to check both the
refcount and the list as well as avoids taking a ref for each entry on the
list.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The normal code pattern used in the kernel is: get/put.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
free_pcppages_bulk() frees pages from pcp lists in a round-robin fashion
by keeping batch_free counter. But it doesn't need to spin if there is
only one non-empty list. This can be checked by batch_free ==
MIGRATE_PCPTYPES.
[akpm@linux-foundation.org: fix comment]
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now we renamed remove_from_page_cache with delete_from_page_cache. As
consistency of __remove_from_swap_cache and remove_from_swap_cache, we
change internal page cache handling function name, too.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now delete_from_page_cache() replaces remove_from_page_cache(). So we
remove remove_from_page_cache so fs or something out of mainline will
notice it when compile time and can fix it.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch series changes remove_from_page_cache()'s page ref counting
rule. Page cache ref count is decreased in delete_from_page_cache(). So
we don't need to decrease the page reference in callers.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch series changes remove_from_page_cache()'s page ref counting
rule. Page cache ref count is decreased in delete_from_page_cache(). So
we don't need to decrease the page reference in callers.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Presently we increase the page refcount in add_to_page_cache() but don't
decrease it in remove_from_page_cache(). Such asymmetry adds confusion,
requiring that callers notice it and a comment explaining why they release
a page reference. It's not a good API.
A long time ago, Hugh tried it (http://lkml.org/lkml/2004/10/24/140) but
gave up because reiser4's drop_page() had to unlock the page between
removing it from page cache and doing the page_cache_release(). But now
the situation is changed. I think at least things in current mainline
don't have any obstacles. The problem is for out-of-mainline filesystems
- if they have done such things as reiser4, this patch could be a problem
but they will discover this at compile time since we remove
remove_from_page_cache().
This patch:
This function works as just wrapper remove_from_page_cache(). The
difference is that it decreases page references in itself. So caller have
to make sure it has a page reference before calling.
This patch is ready for removing remove_from_page_cache().
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Edward Shishkin <edward.shishkin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This function basically does:
remove_from_page_cache(old);
page_cache_release(old);
add_to_page_cache_locked(new);
Except it does this atomically, so there's no possibility for the "add" to
fail because of a race.
If memory cgroups are enabled, then the memory cgroup charge is also moved
from the old page to the new.
This function is currently used by fuse to move pages into the page cache
on read, instead of copying the page contents.
[minchan.kim@gmail.com: add freepage() hook to replace_page_cache_page()]
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
GUP user may want to try to acquire a reference to a page if it is already
in memory, but not if IO, to bring it in, is needed. For example KVM may
tell vcpu to schedule another guest process if current one is trying to
access swapped out page. Meanwhile, the page will be swapped in and the
guest process, that depends on it, will be able to run again.
This patch adds FAULT_FLAG_RETRY_NOWAIT (suggested by Linus) and
FOLL_NOWAIT follow_page flags. FAULT_FLAG_RETRY_NOWAIT, when used in
conjunction with VM_FAULT_ALLOW_RETRY, indicates to handle_mm_fault that
it shouldn't drop mmap_sem and wait on a page, but return VM_FAULT_RETRY
instead.
[akpm@linux-foundation.org: improve FOLL_NOWAIT comment]
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While looking at some other notifier callbacks I noticed this code could
use a simple cleanup.
notifier_from_errno() no longer needs the if (ret)/else conditional. That
same conditional is now done in notifier_from_errno().
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Displaying extremely verbose meminfo for all nodes on the system is
overkill for page allocation failures when the context restricts that
allocation to only a subset of nodes. We don't particularly care about
the state of all nodes when some are not allowed in the current context,
they can have an abundance of memory but we can't allocate from that part
of memory.
This patch suppresses disallowed nodes from the meminfo dump on a page
allocation failure if the context requires it.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a page allocation failure occurs, show_mem() is called to dump the
state of the VM so users may understand what happened to get into that
condition.
This output, however, can be extremely verbose. In irq context, it may
result in significant delays that incur NMI watchdog timeouts when the
machine is large (we use CONFIG_NODES_SHIFT > 8 here to define a "large"
machine since the length of the show_mem() output is proportional to the
number of possible nodes).
This patch suppresses the show_mem() call in irq context when the kernel
has CONFIG_NODES_SHIFT > 8.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The oom killer is extremely verbose for machines with a large number of
cpus and/or nodes. This verbosity can often be harmful if it causes other
important messages to be scrolled from the kernel log and incurs a
signicant time delay, specifically for kernels with CONFIG_NODES_SHIFT >
8.
This patch causes only memory information to be displayed for nodes that
are allowed by current's cpuset when dumping the VM state. Information
for all other nodes is irrelevant to the oom condition; we don't care if
there's an abundance of memory elsewhere if we can't access it.
This only affects the behavior of dumping memory information when an oom
is triggered. Other dumps, such as for sysrq+m, still display the
unfiltered form when using the existing show_mem() interface.
Additionally, the per-cpu pageset statistics are extremely verbose in oom
killer output, so it is now suppressed. This removes
nodes_weight(current->mems_allowed) * (1 + nr_cpus)
lines from the oom killer output.
Callers may use __show_mem(SHOW_MEM_FILTER_NODES) to filter disallowed
nodes.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Many migrate_page's caller check return value instead of list_empy by
cf608ac19c ("mm: compaction: fix COMPACTPAGEFAILED counting"). This patch
makes compaction's migrate_pages consistent with others. This patch
should not change old behavior.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch reverts 5a03b051 ("thp: use compaction in kswapd for GFP_ATOMIC
order > 0") due to reports stating that kswapd CPU usage was higher and
IRQs were being disabled more frequently. This was reported at
http://www.spinics.net/linux/fedora/alsa-user/msg09885.html.
Without this patch applied, CPU usage by kswapd hovers around the 20% mark
according to the tester (Arthur Marsh:
http://www.spinics.net/linux/fedora/alsa-user/msg09899.html). With this
patch applied, it's around 2%.
The problem is not related to THP which specifies __GFP_NO_KSWAPD but is
triggered by high-order allocations hitting the low watermark for their
order and waking kswapd on kernels with CONFIG_COMPACTION set. The most
common trigger for this is network cards configured for jumbo frames but
it's also possible it'll be triggered by fork-heavy workloads (order-1)
and some wireless cards which depend on order-1 allocations.
The symptoms for the user will be high CPU usage by kswapd in low-memory
situations which could be confused with another writeback problem. While
a patch like 5a03b051 may be reintroduced in the future, this patch plays
it safe for now and reverts it.
[mel@csn.ul.ie: Beefed up the changelog]
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reported-by: Arthur Marsh <arthur.marsh@internode.on.net>
Tested-by: Arthur Marsh <arthur.marsh@internode.on.net>
Cc: <stable@kernel.org> [2.6.38.1]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Provide a free area cache for the vmalloc virtual address allocator, based
on the algorithm used by the user virtual memory allocator.
This reduces the number of rbtree operations and linear traversals over
the vmap extents in order to find a free area, by starting off at the last
point that a free area was found.
The free area cache is reset if areas are freed behind it, or if we are
searching for a smaller area or alignment than last time. So allocation
patterns are not changed (verified by corner-case and random test cases in
userspace testing).
This solves a regression caused by lazy vunmap TLB purging introduced in
db64fe02 (mm: rewrite vmap layer). That patch will leave extents in the
vmap allocator after they are vunmapped, and until a significant number
accumulate that can be flushed in a single batch. So in a workload that
vmalloc/vfree frequently, a chain of extents will build up from
VMALLOC_START address, which have to be iterated over each time (giving an
O(n) type of behaviour).
After this patch, the search will start from where it left off, giving
closer to an amortized O(1).
This is verified to solve regressions reported Steven in GFS2, and Avi in
KVM.
Hugh's update:
: I tried out the recent mmotm, and on one machine was fortunate to hit
: the BUG_ON(first->va_start < addr) which seems to have been stalling
: your vmap area cache patch ever since May.
: I can get you addresses etc, I did dump a few out; but once I stared
: at them, it was easier just to look at the code: and I cannot see how
: you would be so sure that first->va_start < addr, once you've done
: that addr = ALIGN(max(...), align) above, if align is over 0x1000
: (align was 0x8000 or 0x4000 in the cases I hit: ioremaps like Steve).
: I originally got around it by just changing the
: if (first->va_start < addr) {
: to
: while (first->va_start < addr) {
: without thinking about it any further; but that seemed unsatisfactory,
: why would we want to loop here when we've got another very similar
: loop just below it?
: I am never going to admit how long I've spent trying to grasp your
: "while (n)" rbtree loop just above this, the one with the peculiar
: if (!first && tmp->va_start < addr + size)
: in. That's unfamiliar to me, I'm guessing it's designed to save a
: subsequent rb_next() in a few circumstances (at risk of then setting
: a wrong cached_hole_size?); but they did appear few to me, and I didn't
: feel I could sign off something with that in when I don't grasp it,
: and it seems responsible for extra code and mistaken BUG_ON below it.
: I've reverted to the familiar rbtree loop that find_vma() does (but
: with va_end >= addr as you had, to respect the additional guard page):
: and then (given that cached_hole_size starts out 0) I don't see the
: need for any complications below it. If you do want to keep that loop
: as you had it, please add a comment to explain what it's trying to do,
: and where addr is relative to first when you emerge from it.
: Aren't your tests "size <= cached_hole_size" and
: "addr + size > first->va_start" forgetting the guard page we want
: before the next area? I've changed those.
: I have not changed your many "addr + size - 1 < addr" overflow tests,
: but have since come to wonder, shouldn't they be "addr + size < addr"
: tests - won't the vend checks go wrong if addr + size is 0?
: I have added a few comments - Wolfgang Wander's 2.6.13 description of
: 1363c3cd86 Avoiding mmap fragmentation
: helped me a lot, perhaps a pointer to that would be good too. And I found
: it easier to understand when I renamed cached_start slightly and moved the
: overflow label down.
: This patch would go after your mm-vmap-area-cache.patch in mmotm.
: Trivially, nobody is going to get that BUG_ON with this patch, and it
: appears to work fine on my machines; but I have not given it anything like
: the testing you did on your original, and may have broken all the
: performance you were aiming for. Please take a look and test it out
: integrate with yours if you're satisfied - thanks.
[akpm@linux-foundation.org: add locking comment]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reported-and-tested-by: Steven Whitehouse <swhiteho@redhat.com>
Reported-and-tested-by: Avi Kivity <avi@redhat.com>
Tested-by: "Barry J. Marson" <bmarson@redhat.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The oom killer naturally defers killing anything if it finds an eligible
task that is already exiting and has yet to detach its ->mm. This avoids
unnecessarily killing tasks when one is already in the exit path and may
free enough memory that the oom killer is no longer needed. This is
detected by PF_EXITING since threads that have already detached its ->mm
are no longer considered at all.
The problem with always deferring when a thread is PF_EXITING, however, is
that it may never actually exit when being traced, specifically if another
task is tracing it with PTRACE_O_TRACEEXIT. The oom killer does not want
to defer in this case since there is no guarantee that thread will ever
exit without intervention.
This patch will now only defer the oom killer when a thread is PF_EXITING
and no ptracer has stopped its progress in the exit path. It also ensures
that a child is sacrificed for the chosen parent only if it has a
different ->mm as the comment implies: this ensures that the thread group
leader is always targeted appropriately.
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrey Vagin <avagin@openvz.org>
Cc: <stable@kernel.org> [2.6.38.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We shouldn't defer oom killing if a thread has already detached its ->mm
and still has TIF_MEMDIE set. Memory needs to be freed, so find kill
other threads that pin the same ->mm or find another task to kill.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@kernel.org> [2.6.38.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch prevents unnecessary oom kills or kernel panics by reverting
two commits:
495789a5 (oom: make oom_score to per-process value)
cef1d352 (oom: multi threaded process coredump don't make deadlock)
First, 495789a5 (oom: make oom_score to per-process value) ignores the
fact that all threads in a thread group do not necessarily exit at the
same time.
It is imperative that select_bad_process() detect threads that are in the
exit path, specifically those with PF_EXITING set, to prevent needlessly
killing additional tasks. If a process is oom killed and the thread group
leader exits, select_bad_process() cannot detect the other threads that
are PF_EXITING by iterating over only processes. Thus, it currently
chooses another task unnecessarily for oom kill or panics the machine when
nothing else is eligible.
By iterating over threads instead, it is possible to detect threads that
are exiting and nominate them for oom kill so they get access to memory
reserves.
Second, cef1d352 (oom: multi threaded process coredump don't make
deadlock) erroneously avoids making the oom killer a no-op when an
eligible thread other than current isfound to be exiting. We want to
detect this situation so that we may allow that exiting thread time to
exit and free its memory; if it is able to exit on its own, that should
free memory so current is no loner oom. If it is not able to exit on its
own, the oom killer will nominate it for oom kill which, in this case,
only means it will get access to memory reserves.
Without this change, it is easy for the oom killer to unnecessarily target
tasks when all threads of a victim don't exit before the thread group
leader or, in the worst case, panic the machine.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrey Vagin <avagin@openvz.org>
Cc: <stable@kernel.org> [2.6.38.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If an administrator tries to swapon a file backed by NFS, the inode mutex is
taken (as it is for any swapfile) but later identified to be a bad swapfile
due to the lack of bmap and tries to cleanup. During cleanup, an attempt is
made to close the file but with inode->i_mutex still held. Closing an NFS
file syncs it which tries to acquire the inode mutex leading to deadlock. If
lockdep is enabled the following appears on the console;
=============================================
[ INFO: possible recursive locking detected ]
2.6.38-rc8-autobuild #1
---------------------------------------------
swapon/2192 is trying to acquire lock:
(&sb->s_type->i_mutex_key#13){+.+.+.}, at: vfs_fsync_range+0x47/0x7c
but task is already holding lock:
(&sb->s_type->i_mutex_key#13){+.+.+.}, at: sys_swapon+0x28d/0xae7
other info that might help us debug this:
1 lock held by swapon/2192:
#0: (&sb->s_type->i_mutex_key#13){+.+.+.}, at: sys_swapon+0x28d/0xae7
stack backtrace:
Pid: 2192, comm: swapon Not tainted 2.6.38-rc8-autobuild #1
Call Trace:
__lock_acquire+0x2eb/0x1623
find_get_pages_tag+0x14a/0x174
pagevec_lookup_tag+0x25/0x2e
vfs_fsync_range+0x47/0x7c
lock_acquire+0xd3/0x100
vfs_fsync_range+0x47/0x7c
nfs_flush_one+0x0/0xdf [nfs]
mutex_lock_nested+0x40/0x2b1
vfs_fsync_range+0x47/0x7c
vfs_fsync_range+0x47/0x7c
vfs_fsync+0x1c/0x1e
nfs_file_flush+0x64/0x69 [nfs]
filp_close+0x43/0x72
sys_swapon+0xa39/0xae7
sysret_check+0x2e/0x69
system_call_fastpath+0x16/0x1b
This patch releases the mutex if its held before calling filep_close()
so swapon fails as expected without deadlock when the swapfile is backed
by NFS. If accepted for 2.6.39, it should also be considered a -stable
candidate for 2.6.38 and 2.6.37.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: <stable@kernel.org> [2.6.37+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
OOM path is missing the irq restore in the CONFIG_CMPXCHG_LOCAL case.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
slub: Dont define useless label in the !CONFIG_CMPXCHG_LOCAL case
slab,rcu: don't assume the size of struct rcu_head
slub,rcu: don't assume the size of struct rcu_head
slub: automatically reserve bytes at the end of slab
Lockless (and preemptless) fastpaths for slub
slub: Get rid of slab_free_hook_irq()
slub: min_partial needs to be in first cacheline
slub: fix ksize() build error
slub: fix kmemcheck calls to match ksize() hints
Revert "slab: Fix missing DEBUG_SLAB last user"
mm: Remove support for kmem_cache_name()
The redo label needs #ifdeffery. Fixes the following problem introduced by
commit 8a5ec0ba42 ("Lockless (and preemptless) fastpaths for slub"):
mm/slub.c: In function 'slab_free':
mm/slub.c:2124: warning: label 'redo' defined but not used
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (47 commits)
doc: CONFIG_UNEVICTABLE_LRU doesn't exist anymore
Update cpuset info & webiste for cgroups
dcdbas: force SMI to happen when expected
arch/arm/Kconfig: remove one to many l's in the word.
asm-generic/user.h: Fix spelling in comment
drm: fix printk typo 'sracth'
Remove one to many n's in a word
Documentation/filesystems/romfs.txt: fixing link to genromfs
drivers:scsi Change printk typo initate -> initiate
serial, pch uart: Remove duplicate inclusion of linux/pci.h header
fs/eventpoll.c: fix spelling
mm: Fix out-of-date comments which refers non-existent functions
drm: Fix printk typo 'failled'
coh901318.c: Change initate to initiate.
mbox-db5500.c Change initate to initiate.
edac: correct i82975x error-info reported
edac: correct i82975x mci initialisation
edac: correct commented info
fs: update comments to point correct document
target: remove duplicate include of target/target_core_device.h from drivers/target/target_core_hba.c
...
Trivial conflict in fs/eventpoll.c (spelling vs addition)
* 'kvm-updates/2.6.39' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (55 commits)
KVM: unbreak userspace that does not sets tss address
KVM: MMU: cleanup pte write path
KVM: MMU: introduce a common function to get no-dirty-logged slot
KVM: fix rcu usage in init_rmode_* functions
KVM: fix kvmclock regression due to missing clock update
KVM: emulator: Fix permission checking in io permission bitmap
KVM: emulator: Fix io permission checking for 64bit guest
KVM: SVM: Load %gs earlier if CONFIG_X86_32_LAZY_GS=n
KVM: x86: Remove useless regs_page pointer from kvm_lapic
KVM: improve comment on rcu use in irqfd_deassign
KVM: MMU: remove unused macros
KVM: MMU: cleanup page alloc and free
KVM: MMU: do not record gfn in kvm_mmu_pte_write
KVM: MMU: move mmu pages calculated out of mmu lock
KVM: MMU: set spte accessed bit properly
KVM: MMU: fix kvm_mmu_slot_remove_write_access dropping intermediate W bits
KVM: Start lock documentation
KVM: better readability of efer_reserved_bits
KVM: Clear async page fault hash after switching to real mode
KVM: VMX: Initialize vm86 TSS only once.
...
Change the _mapcount value indicating PageBuddy from -2 to -128 for
more robusteness against page_mapcount() undeflows.
Use reset_page_mapcount instead of __ClearPageBuddy in bad_page to
ignore the previous retval of PageBuddy().
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make __get_user_pages return -EHWPOISON for HWPOISON page only if
FOLL_HWPOISON is specified. With this patch, the interested callers
can distinguish HWPOISON pages from general FAULT pages, while other
callers will still get -EFAULT for all these pages, so the user space
interface need not to be changed.
This feature is needed by KVM, where UCR MCE should be relayed to
guest for HWPOISON page, while instruction emulation and MMIO will be
tried for general FAULT page.
The idea comes from Andrew Morton.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
In most cases, get_user_pages and get_user_pages_fast should be used
to pin user pages in memory. But sometimes, some special flags except
FOLL_GET, FOLL_WRITE and FOLL_FORCE are needed, for example in
following patch, KVM needs FOLL_HWPOISON. To support these users,
__get_user_pages is exported directly.
There are some symbol name conflicts in infiniband driver, fixed them too.
Signed-off-by: Huang Ying <ying.huang@intel.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Michel Lespinasse <walken@google.com>
CC: Roland Dreier <roland@kernel.org>
CC: Ralph Campbell <infinipath@qlogic.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
We don't have proper reference counting for this yet, so we run into
cases where the device is pulled and we OOPS on flushing the fs data.
This happens even though the dirty inodes have already been
migrated to the default_backing_dev_info.
Reported-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Tested-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6: (33 commits)
AppArmor: kill unused macros in lsm.c
AppArmor: cleanup generated files correctly
KEYS: Add an iovec version of KEYCTL_INSTANTIATE
KEYS: Add a new keyctl op to reject a key with a specified error code
KEYS: Add a key type op to permit the key description to be vetted
KEYS: Add an RCU payload dereference macro
AppArmor: Cleanup make file to remove cruft and make it easier to read
SELinux: implement the new sb_remount LSM hook
LSM: Pass -o remount options to the LSM
SELinux: Compute SID for the newly created socket
SELinux: Socket retains creator role and MLS attribute
SELinux: Auto-generate security_is_socket_class
TOMOYO: Fix memory leak upon file open.
Revert "selinux: simplify ioctl checking"
selinux: drop unused packet flow permissions
selinux: Fix packet forwarding checks on postrouting
selinux: Fix wrong checks for selinux_policycap_netpeer
selinux: Fix check for xfrm selinux context algorithm
ima: remove unnecessary call to ima_must_measure
IMA: remove IMA imbalance checking
...
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (93 commits)
x86, tlb, UV: Do small micro-optimization for native_flush_tlb_others()
x86-64, NUMA: Don't call numa_set_distanc() for all possible node combinations during emulation
x86-64, NUMA: Don't assume phys node 0 is always online in numa_emulation()
x86-64, NUMA: Clean up initmem_init()
x86-64, NUMA: Fix numa_emulation code with node0 without RAM
x86-64, NUMA: Revert NUMA affine page table allocation
x86: Work around old gas bug
x86-64, NUMA: Better explain numa_distance handling
x86-64, NUMA: Fix distance table handling
mm: Move early_node_map[] reverse scan helpers under HAVE_MEMBLOCK
x86-64, NUMA: Fix size of numa_distance array
x86: Rename e820_table_* to pgt_buf_*
bootmem: Move __alloc_memory_core_early() to nobootmem.c
bootmem: Move contig_page_data definition to bootmem.c/nobootmem.c
bootmem: Separate out CONFIG_NO_BOOTMEM code into nobootmem.c
x86-64, NUMA: Seperate out numa_alloc_distance() from numa_set_distance()
x86-64, NUMA: Add proper function comments to global functions
x86-64, NUMA: Move NUMA emulation into numa_emulation.c
x86-64, NUMA: Prepare numa_emulation() for moving NUMA emulation into a separate file
x86-64, NUMA: Do not scan two times for setup_node_bootmem()
...
Fix up conflicts in arch/x86/kernel/smpboot.c
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (57 commits)
tidy the trailing symlinks traversal up
Turn resolution of trailing symlinks iterative everywhere
simplify link_path_walk() tail
Make trailing symlink resolution in path_lookupat() iterative
update nd->inode in __do_follow_link() instead of after do_follow_link()
pull handling of one pathname component into a helper
fs: allow AT_EMPTY_PATH in linkat(), limit that to CAP_DAC_READ_SEARCH
Allow passing O_PATH descriptors via SCM_RIGHTS datagrams
readlinkat(), fchownat() and fstatat() with empty relative pathnames
Allow O_PATH for symlinks
New kind of open files - "location only".
ext4: Copy fs UUID to superblock
ext3: Copy fs UUID to superblock.
vfs: Export file system uuid via /proc/<pid>/mountinfo
unistd.h: Add new syscalls numbers to asm-generic
x86: Add new syscalls for x86_64
x86: Add new syscalls for x86_32
fs: Remove i_nlink check from file system link callback
fs: Don't allow to create hardlink for deleted file
vfs: Add open by file handle support
...
This reverts the parent commit. I hate doing that, but it's generating
some discussion ("half of it is right"), and since I am planning on
doing the 2.6.38 release later today we can punt it to stable if
required. Let's not rock the boat right now.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
oom_kill_process() starts with victim_points == 0. This means that
(most likely) any child has more points and can be killed erroneously.
Also, "children has a different mm" doesn't match the reality, we should
check child->mm != t->mm. This check is not exactly correct if t->mm ==
NULL but this doesn't really matter, oom_kill_task() will kill them
anyway.
Note: "Kill all processes sharing p->mm" in oom_kill_task() is wrong
too.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
THP's collapse_huge_page() has an understandable but ugly difference
in when its huge page is allocated: inside if NUMA but outside if not.
It's hardly surprising that the memcg failure path forgot that, freeing
the page in the non-NUMA case, then hitting a VM_BUG_ON in get_page()
(or even worse, using the freed page).
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The exportfs encode handle function should return the minimum required
handle size. This helps user to find out the handle size by passing 0
handle size in the first step and then redoing to the call again with
the returned handle size value.
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When vmscan.c calls page_referenced(), if an anon page was created
before a process forked, rmap will search for it in both of the
processes, even though one of them might have since broken COW.
If the child process mlocks the vma where the COWed page belongs to,
page_referenced() running on the page mapped by the parent would lead to
*vm_flags getting VM_LOCKED set erroneously (leading to the references
on the parent page being ignored and evicting the parent page too
early).
*mapcount would also be decremented by page_referenced_one even if the
page wasn't found by page_check_address.
This also lets pmdp_clear_flush_young_notify() go ahead on a
pmd_trans_splitting() pmd.
We hold the page_table_lock so __split_huge_page_map() must wait the
pmdp_clear_flush_young_notify() to complete before it can modify the
pmd. The pmd is also still mapped in userland so the young bit may
materialize through a tlb miss before split_huge_page_map runs.
This will provide a more accurate page_referenced() behavior during
split_huge_page().
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel<riel@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The size of struct rcu_head may be changed. When it becomes larger,
it may pollute the data after struct slab.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
The size of struct rcu_head may be changed. When it becomes larger,
it will pollute the page array.
We reserve some some bytes for struct rcu_head when a slab
is allocated in this situation.
Changed from V1:
use VM_BUG_ON instead BUG_ON
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
There is no "struct" for slub's slab, it shares with struct page.
But struct page is very small, it is insufficient when we need
to add some metadata for slab.
So we add a field "reserved" to struct kmem_cache, when a slab
is allocated, kmem_cache->reserved bytes are automatically reserved
at the end of the slab for slab's metadata.
Changed from v1:
Export the reserved field via sysfs
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Use the this_cpu_cmpxchg_double functionality to implement a lockless
allocation algorithm on arches that support fast this_cpu_ops.
Each of the per cpu pointers is paired with a transaction id that ensures
that updates of the per cpu information can only occur in sequence on
a certain cpu.
A transaction id is a "long" integer that is comprised of an event number
and the cpu number. The event number is incremented for every change to the
per cpu state. This means that the cmpxchg instruction can verify for an
update that nothing interfered and that we are updating the percpu structure
for the processor where we picked up the information and that we are also
currently on that processor when we update the information.
This results in a significant decrease of the overhead in the fastpaths. It
also makes it easy to adopt the fast path for realtime kernels since this
is lockless and does not require the use of the current per cpu area
over the critical section. It is only important that the per cpu area is
current at the beginning of the critical section and at the end.
So there is no need even to disable preemption.
Test results show that the fastpath cycle count is reduced by up to ~ 40%
(alloc/free test goes from ~140 cycles down to ~80). The slowpath for kfree
adds a few cycles.
Sadly this does nothing for the slowpath which is where the main issues with
performance in slub are but the best case performance rises significantly.
(For that see the more complex slub patches that require cmpxchg_double)
Kmalloc: alloc/free test
Before:
10000 times kmalloc(8)/kfree -> 134 cycles
10000 times kmalloc(16)/kfree -> 152 cycles
10000 times kmalloc(32)/kfree -> 144 cycles
10000 times kmalloc(64)/kfree -> 142 cycles
10000 times kmalloc(128)/kfree -> 142 cycles
10000 times kmalloc(256)/kfree -> 132 cycles
10000 times kmalloc(512)/kfree -> 132 cycles
10000 times kmalloc(1024)/kfree -> 135 cycles
10000 times kmalloc(2048)/kfree -> 135 cycles
10000 times kmalloc(4096)/kfree -> 135 cycles
10000 times kmalloc(8192)/kfree -> 144 cycles
10000 times kmalloc(16384)/kfree -> 754 cycles
After:
10000 times kmalloc(8)/kfree -> 78 cycles
10000 times kmalloc(16)/kfree -> 78 cycles
10000 times kmalloc(32)/kfree -> 82 cycles
10000 times kmalloc(64)/kfree -> 88 cycles
10000 times kmalloc(128)/kfree -> 79 cycles
10000 times kmalloc(256)/kfree -> 79 cycles
10000 times kmalloc(512)/kfree -> 85 cycles
10000 times kmalloc(1024)/kfree -> 82 cycles
10000 times kmalloc(2048)/kfree -> 82 cycles
10000 times kmalloc(4096)/kfree -> 85 cycles
10000 times kmalloc(8192)/kfree -> 82 cycles
10000 times kmalloc(16384)/kfree -> 706 cycles
Kmalloc: Repeatedly allocate then free test
Before:
10000 times kmalloc(8) -> 211 cycles kfree -> 113 cycles
10000 times kmalloc(16) -> 174 cycles kfree -> 115 cycles
10000 times kmalloc(32) -> 235 cycles kfree -> 129 cycles
10000 times kmalloc(64) -> 222 cycles kfree -> 120 cycles
10000 times kmalloc(128) -> 343 cycles kfree -> 139 cycles
10000 times kmalloc(256) -> 827 cycles kfree -> 147 cycles
10000 times kmalloc(512) -> 1048 cycles kfree -> 272 cycles
10000 times kmalloc(1024) -> 2043 cycles kfree -> 528 cycles
10000 times kmalloc(2048) -> 4002 cycles kfree -> 571 cycles
10000 times kmalloc(4096) -> 7740 cycles kfree -> 628 cycles
10000 times kmalloc(8192) -> 8062 cycles kfree -> 850 cycles
10000 times kmalloc(16384) -> 8895 cycles kfree -> 1249 cycles
After:
10000 times kmalloc(8) -> 190 cycles kfree -> 129 cycles
10000 times kmalloc(16) -> 76 cycles kfree -> 123 cycles
10000 times kmalloc(32) -> 126 cycles kfree -> 124 cycles
10000 times kmalloc(64) -> 181 cycles kfree -> 128 cycles
10000 times kmalloc(128) -> 310 cycles kfree -> 140 cycles
10000 times kmalloc(256) -> 809 cycles kfree -> 165 cycles
10000 times kmalloc(512) -> 1005 cycles kfree -> 269 cycles
10000 times kmalloc(1024) -> 1999 cycles kfree -> 527 cycles
10000 times kmalloc(2048) -> 3967 cycles kfree -> 570 cycles
10000 times kmalloc(4096) -> 7658 cycles kfree -> 637 cycles
10000 times kmalloc(8192) -> 8111 cycles kfree -> 859 cycles
10000 times kmalloc(16384) -> 8791 cycles kfree -> 1173 cycles
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
The following patch will make the fastpaths lockless and will no longer
require interrupts to be disabled. Calling the free hook with irq disabled
will no longer be possible.
Move the slab_free_hook_irq() logic into slab_free_hook. Only disable
interrupts if the features are selected that require callbacks with
interrupts off and reenable after calls have been made.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
With the plugging now being explicitly controlled by the
submitter, callers need not pass down unplugging hints
to the block layer. If they want to unplug, it's because they
manually plugged on their own - in which case, they should just
unplug at will.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
