27 May, 2011
1 commit
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This fourth patch of eight in this cleancache series provides the
core hooks in VFS for: initializing cleancache per filesystem;
capturing clean pages reclaimed by page cache; attempting to get
pages from cleancache before filesystem read; and ensuring coherency
between pagecache, disk, and cleancache. Note that the placement
of these hooks was stable from 2.6.18 to 2.6.38; a minor semantic
change was required due to a patchset in 2.6.39.All hooks become no-ops if CONFIG_CLEANCACHE is unset, or become
a check of a boolean global if CONFIG_CLEANCACHE is set but no
cleancache "backend" has claimed cleancache_ops.Details and a FAQ can be found in Documentation/vm/cleancache.txt
[v8: minchan.kim@gmail.com: adapt to new remove_from_page_cache function]
Signed-off-by: Chris Mason
Signed-off-by: Dan Magenheimer
Reviewed-by: Jeremy Fitzhardinge
Reviewed-by: Konrad Rzeszutek Wilk
Cc: Andrew Morton
Cc: Al Viro
Cc: Matthew Wilcox
Cc: Nick Piggin
Cc: Mel Gorman
Cc: Rik Van Riel
Cc: Jan Beulich
Cc: Andreas Dilger
Cc: Ted Ts'o
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Nitin Gupta
23 Mar, 2011
3 commits
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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
Reported-by: Ben Gamari
Signed-off-by: Peter Zijlstra
Acked-by: Rik van Riel
Acked-by: Mel Gorman
Reviewed-by: KOSAKI Motohiro
Cc: Wu Fengguang
Acked-by: Johannes Weiner
Cc: Nick Piggin
Cc: Andrea Arcangeli
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Cc: Christoph Hellwig
Acked-by: Hugh Dickins
Acked-by: Mel Gorman
Reviewed-by: KAMEZAWA Hiroyuki
Reviewed-by: Johannes Weiner
Reviewed-by: KOSAKI Motohiro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Cc: Dan Magenheimer
Cc: Andi Kleen
Cc: Nick Piggin
Cc: Al Viro
Acked-by: Hugh Dickins
Acked-by: Mel Gorman
Reviewed-by: KAMEZAWA Hiroyuki
Reviewed-by: Johannes Weiner
Reviewed-by: KOSAKI Motohiro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
26 Feb, 2011
1 commit
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It seems odd that truncate_inode_pages_range(), called not only when
truncating but also when evicting inodes, has mem_cgroup_uncharge_start
and _end() batching in its second loop to clear up a few leftovers, but
not in its first loop that does almost all the work: add them there too.Signed-off-by: Hugh Dickins
Acked-by: KAMEZAWA Hiroyuki
Acked-by: Balbir Singh
Acked-by: Daisuke Nishimura
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
21 Jan, 2011
1 commit
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Contrary to what the comment says, truncate_setsize() should be called
*before* filesystem truncated blocks.Signed-off-by: Jan Kara
Cc: Christoph Hellwig
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
02 Dec, 2010
1 commit
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NFS needs to be able to release objects that are stored in the page
cache once the page itself is no longer visible from the page cache.This patch adds a callback to the address space operations that allows
filesystems to perform page cleanups once the page has been removed
from the page cache.Original patch by: Linus Torvalds
[trondmy: cover the cases of invalidate_inode_pages2() and
truncate_inode_pages()]
Signed-off-by: Trond Myklebust
10 Aug, 2010
1 commit
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Make sure we check the truncate constraints early on in ->setattr by adding
those checks to inode_change_ok. Also clean up and document inode_change_ok
to make this obvious.As a fallout we don't have to call inode_newsize_ok from simple_setsize and
simplify it down to a truncate_setsize which doesn't return an error. This
simplifies a lot of setattr implementations and means we use truncate_setsize
almost everywhere. Get rid of fat_setsize now that it's trivial and mark
ext2_setsize static to make the calling convention obvious.Keep the inode_newsize_ok in vmtruncate for now as all callers need an
audit for its removal anyway.Note: setattr code in ecryptfs doesn't call inode_change_ok at all and
needs a deeper audit, but that is left for later.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro
28 May, 2010
1 commit
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Introduce a new truncate calling sequence into fs/mm subsystems. Rather than
setattr > vmtruncate > truncate, have filesystems call their truncate sequence
from ->setattr if filesystem specific operations are required. vmtruncate is
deprecated, and truncate_pagecache and inode_newsize_ok helpers introduced
previously should be used.simple_setattr is introduced for simple in-ram filesystems to implement
the new truncate sequence. Eventually all filesystems should be converted
to implement a setattr, and the default code in notify_change should go
away.simple_setsize is also introduced to perform just the ATTR_SIZE portion
of simple_setattr (ie. changing i_size and trimming pagecache).To implement the new truncate sequence:
- filesystem specific manipulations (eg freeing blocks) must be done in
the setattr method rather than ->truncate.
- vmtruncate can not be used by core code to trim blocks past i_size in
the event of write failure after allocation, so this must be performed
in the fs code.
- convert usage of helpers block_write_begin, nobh_write_begin,
cont_write_begin, and *blockdev_direct_IO* to use _newtrunc postfixed
variants. These avoid calling vmtruncate to trim blocks (see previous).
- inode_setattr should not be used. generic_setattr is a new function
to be used to copy simple attributes into the generic inode.
- make use of the better opportunity to handle errors with the new sequence.Big problem with the previous calling sequence: the filesystem is not called
until i_size has already changed. This means it is not allowed to fail the
call, and also it does not know what the previous i_size was. Also, generic
code calling vmtruncate to truncate allocated blocks in case of error had
no good way to return a meaningful error (or, for example, atomically handle
block deallocation).Cc: Christoph Hellwig
Acked-by: Jan Kara
Signed-off-by: Nick Piggin
Signed-off-by: Al Viro
30 Mar, 2010
1 commit
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…it slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
14 Jan, 2010
1 commit
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If __block_prepare_write() was failed in block_write_begin(), the
allocated blocks can be outside of ->i_size.But new truncate_pagecache() in vmtuncate() does nothing if new < old.
It means the above usage is not working anymore.So, this patch fixes it by removing "new < old" check. It would need
more cleanup/change. But, now -rc and truncate working is in progress,
so, this tried to fix it minimum change.Acked-by: Nick Piggin
Signed-off-by: OGAWA Hirofumi
Signed-off-by: Linus Torvalds
16 Dec, 2009
1 commit
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In massive parallel enviroment, res_counter can be a performance
bottleneck. One strong techinque to reduce lock contention is reducing
calls by coalescing some amount of calls into one.Considering charge/uncharge chatacteristic,
- charge is done one by one via demand-paging.
- uncharge is done by
- in chunk at munmap, truncate, exit, execve...
- one by one via vmscan/paging.It seems we have a chance to coalesce uncharges for improving scalability
at unmap/truncation.This patch is a for coalescing uncharge. For avoiding scattering memcg's
structure to functions under /mm, this patch adds memcg batch uncharge
information to the task. A reason for per-task batching is for making use
of caller's context information. We do batched uncharge (deleyed
uncharge) when truncation/unmap occurs but do direct uncharge when
uncharge is called by memory reclaim (vmscan.c).The degree of coalescing depends on callers
- at invalidate/trucate... pagevec size
- at unmap ....ZAP_BLOCK_SIZE
(memory itself will be freed in this degree.)
Then, we'll not coalescing too much.On x86-64 8cpu server, I tested overheads of memcg at page fault by
running a program which does map/fault/unmap in a loop. Running
a task per a cpu by taskset and see sum of the number of page faults
in 60secs.[without memcg config]
40156968 page-faults # 0.085 M/sec ( +- 0.046% )
27.67 cache-miss/faults
[root cgroup]
36659599 page-faults # 0.077 M/sec ( +- 0.247% )
31.58 miss/faults
[in a child cgroup]
18444157 page-faults # 0.039 M/sec ( +- 0.133% )
69.96 miss/faults
[child with this patch]
27133719 page-faults # 0.057 M/sec ( +- 0.155% )
47.16 miss/faultsWe can see some amounts of improvement.
(root cgroup doesn't affected by this patch)
Another patch for "charge" will follow this and above will be improved more.Changelog(since 2009/10/02):
- renamed filed of memcg_batch (as pages to bytes, memsw to memsw_bytes)
- some clean up and commentary/description updates.
- added initialize code to copy_process(). (possible bug fix)Changelog(old):
- fixed !CONFIG_MEM_CGROUP case.
- rebased onto the latest mmotm + softlimit fix patches.
- unified patch for callers
- added commetns.
- make ->do_batch as bool.
- removed css_get() at el. We don't need it.Signed-off-by: KAMEZAWA Hiroyuki
Cc: Balbir Singh
Cc: Daisuke Nishimura
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
04 Dec, 2009
1 commit
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invalidate_inode_pages2() returns -EBUSY *NOT* -EIO if any pages could not be
invalidated.Signed-off-by: Peng Tao
Signed-off-by: Jiri Kosina
24 Sep, 2009
2 commits
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* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
truncate: use new helpers
truncate: new helpers
fs: fix overflow in sys_mount() for in-kernel calls
fs: Make unload_nls() NULL pointer safe
freeze_bdev: grab active reference to frozen superblocks
freeze_bdev: kill bd_mount_sem
exofs: remove BKL from super operations
fs/romfs: correct error-handling code
vfs: seq_file: add helpers for data filling
vfs: remove redundant position check in do_sendfile
vfs: change sb->s_maxbytes to a loff_t
vfs: explicitly cast s_maxbytes in fiemap_check_ranges
libfs: return error code on failed attr set
seq_file: return a negative error code when seq_path_root() fails.
vfs: optimize touch_time() too
vfs: optimization for touch_atime()
vfs: split generic_forget_inode() so that hugetlbfs does not have to copy it
fs/inode.c: add dev-id and inode number for debugging in init_special_inode()
libfs: make simple_read_from_buffer conventional -
Introduce new truncate helpers truncate_pagecache and inode_newsize_ok.
vmtruncate is also consolidated from mm/memory.c and mm/nommu.c and
into mm/truncate.c.Reviewed-by: Christoph Hellwig
Signed-off-by: Nick Piggin
Signed-off-by: Al Viro
16 Sep, 2009
3 commits
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Truncating metadata pages is not safe right now before
we haven't audited all file systems.To enable truncation only for data address space define
a new address_space callback error_remove_page.This is used for memory_failure.c memory error handling.
This can be then set to truncate_inode_page()
This patch just defines the new operation and adds documentation.
Callers and users come in followon patches.
Signed-off-by: Andi Kleen
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Add a simple way to invalidate a single page
This is just a refactoring of the truncate.c code.
Originally from Fengguang, modified by Andi Kleen.Signed-off-by: Andi Kleen
-
Extract out truncate_inode_page() out of the truncate path so that
it can be used by memory-failure.c[AK: description, headers, fix typos]
v2: Some white space changes from Fengguang WuSigned-off-by: Andi Kleen
17 Jun, 2009
1 commit
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Remove __invalidate_mapping_pages atomic variant now that its sole caller
can sleep (fixed in eccb95cee4f0d56faa46ef22fb94dd4a3578d3eb ("vfs: fix
lock inversion in drop_pagecache_sb()")).This fixes softlockups that can occur while in the drop_caches path.
Signed-off-by: Mike Waychison
Cc: Jan Kara
Cc: Wu Fengguang
Cc: Dave Chinner
Cc: Nick Piggin
Acked-by: Jan Kara
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 May, 2009
1 commit
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mapping->tree_lock can be acquired from interrupt context. Then,
following dead lock can occur.Assume "A" as a page.
CPU0:
lock_page_cgroup(A)
interrupted
-> take mapping->tree_lock.
CPU1:
take mapping->tree_lock
-> lock_page_cgroup(A)This patch tries to fix above deadlock by moving memcg's hook to out of
mapping->tree_lock. charge/uncharge of pagecache/swapcache is protected
by page lock, not tree_lock.After this patch, lock_page_cgroup() is not called under mapping->tree_lock.
Signed-off-by: KAMEZAWA Hiroyuki
Signed-off-by: Daisuke Nishimura
Cc: Balbir Singh
Cc: Daisuke Nishimura
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
03 Apr, 2009
1 commit
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Recruit a page flag to aid in cache management. The following extra flag is
defined:(1) PG_fscache (PG_private_2)
The marked page is backed by a local cache and is pinning resources in the
cache driver.If PG_fscache is set, then things that checked for PG_private will now also
check for that. This includes things like truncation and page invalidation.
The function page_has_private() had been added to make the checks for both
PG_private and PG_private_2 at the same time.Signed-off-by: David Howells
Acked-by: Steve Dickson
Acked-by: Trond Myklebust
Acked-by: Rik van Riel
Acked-by: Al Viro
Tested-by: Daire Byrne
20 Oct, 2008
1 commit
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Originally by Nick Piggin
Remove mlocked pages from the LRU using "unevictable infrastructure"
during mmap(), munmap(), mremap() and truncate(). Try to move back to
normal LRU lists on munmap() when last mlocked mapping removed. Remove
PageMlocked() status when page truncated from file.[akpm@linux-foundation.org: cleanup]
[kamezawa.hiroyu@jp.fujitsu.com: fix double unlock_page()]
[kosaki.motohiro@jp.fujitsu.com: split LRU: munlock rework]
[lee.schermerhorn@hp.com: mlock: fix __mlock_vma_pages_range comment block]
[akpm@linux-foundation.org: remove bogus kerneldoc token]
Signed-off-by: Nick Piggin
Signed-off-by: Lee Schermerhorn
Signed-off-by: Rik van Riel
Signed-off-by: KOSAKI Motohiro
Signed-off-by: KAMEZAWA Hiroyuki
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Oct, 2008
1 commit
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People can use the real name an an index into MAINTAINERS to find the
current email address.Signed-off-by: Francois Cami
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
03 Sep, 2008
1 commit
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Dio write returns EIO when try_to_release_page fails because bh is
still referenced.The patch
commit 3f31fddfa26b7594b44ff2b34f9a04ba409e0f91
Author: Mingming Cao
Date: Fri Jul 25 01:46:22 2008 -0700jbd: fix race between free buffer and commit transaction
was merged into 2.6.27-rc1, but I noticed that this patch is not enough
to fix the race.I did fsstress test heavily to 2.6.27-rc1, and found that dio write still
sometimes got EIO through this test.The patch above fixed race between freeing buffer(dio) and committing
transaction(jbd) but I discovered that there is another race, freeing
buffer(dio) and ext3/4_ordered_writepage.: background_writeout()
->write_cache_pages()
->ext3_ordered_writepage()
walk_page_buffers() -> take a bh ref
block_write_full_page() -> unlock_page
: try_to_release_page fails)
walk_page_buffers() ->release a bh refext3_ordered_writepage holds bh ref and does unlock_page remaining
taking a bh ref, so this causes the race and failure of
try_to_release_page.To fix this race, I used the approach of falling back to buffered
writes if try_to_release_page() fails on a page.[akpm@linux-foundation.org: cleanups]
Signed-off-by: Hisashi Hifumi
Cc: Chris Mason
Cc: Jan Kara
Cc: Mingming Cao
Cc: Zach Brown
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
05 Aug, 2008
1 commit
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Converting page lock to new locking bitops requires a change of page flag
operation naming, so we might as well convert it to something nicer
(!TestSetPageLocked_Lock => trylock_page, SetPageLocked => set_page_locked).This also facilitates lockdeping of page lock.
Signed-off-by: Nick Piggin
Acked-by: KOSAKI Motohiro
Acked-by: Peter Zijlstra
Acked-by: Andrew Morton
Acked-by: Benjamin Herrenschmidt
Signed-off-by: Linus Torvalds
03 Aug, 2008
1 commit
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Brian Wang reported that a FUSE filesystem exported through NFS could
return I/O errors on read. This was traced to splice_direct_to_actor()
returning a short or zero count when racing with page invalidation.However this is not FUSE or NFSD specific, other filesystems (notably
NFS) also call invalidate_inode_pages2() to purge stale data from the
cache.If this happens while such pages are sitting in a pipe buffer, then
splice(2) from the pipe can return zero, and read(2) from the pipe can
return ENODATA.The zero return is especially bad, since it implies end-of-file or
disconnected pipe/socket, and is documented as such for splice. But
returning an error for read() is also nasty, when in fact there was no
error (data becoming stale is not an error).The same problems can be triggered by "hole punching" with
madvise(MADV_REMOVE).Fix this by not clearing the PG_uptodate flag on truncation and
invalidation.Signed-off-by: Miklos Szeredi
Acked-by: Nick Piggin
Cc: Andrew Morton
Cc: Jens Axboe
Signed-off-by: Linus Torvalds
27 Jul, 2008
1 commit
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mapping->tree_lock has no read lockers. convert the lock from an rwlock
to a spinlock.Signed-off-by: Nick Piggin
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: Hugh Dickins
Cc: "Paul E. McKenney"
Reviewed-by: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
28 Apr, 2008
1 commit
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DIO invalidates page cache through invalidate_inode_pages2_range().
invalidate_inode_pages2_range() sets ret=-EIO when
invalidate_complete_page2() fails, but this ret is cleared if
do_launder_page() succeed on a page of next index.In this case, dio is carried out even if invalidate_complete_page2() fails
on some pages.This can cause inconsistency between memory and blocks on HDD because the
page cache still exists.[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Hisashi Hifumi
Cc: Badari Pulavarty
Cc: Ken Chen
Cc: Zach Brown
Cc: Nick Piggin
Cc: Trond Myklebust
Cc: "J. Bruce Fields"
Cc: Chuck Lever
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
04 Mar, 2008
1 commit
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Fix docbook problems in kernel-api.tmpl.
These cause the generated docbook to be incorrect.Signed-off-by: Randy Dunlap
Signed-off-by: Linus Torvalds
06 Feb, 2008
3 commits
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Orphaned page might have fs-private metadata, the page is truncated. As
the page hasn't mapping, page migration refuse to migrate the page. It
appears the page is only freed in page reclaim and if zone watermark is
low, the page is never freed, as a result migration always fail. I thought
we could free the metadata so such page can be freed in migration and make
migration more reliable.[akpm@linux-foundation.org: go direct to try_to_free_buffers()]
Signed-off-by: Shaohua Li
Acked-by: Nick Piggin
Acked-by: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
In 46d2277c796f9f4937bfa668c40b2e3f43e93dd0 ("Clean up and make
try_to_free_buffers() not race with dirty pages"), try_to_free_buffers
was changed to bail out if the page was dirty.That in turn caused truncate_complete_page to leak massive amounts of
memory, because the dirty bit was only cleared after the call to
try_to_free_buffers.So the call to cancel_dirty_page was moved up to have the dirty bit
cleared early in 3e67c0987d7567ad666641164a153dca9a43b11d ("truncate:
clear page dirtiness before running try_to_free_buffers()").The problem with that fix is, that the page can be redirtied after
cancel_dirty_page was called, eg. like this:truncate_complete_page()
cancel_dirty_page() // PG_dirty cleared, decr. dirty pages
do_invalidatepage()
ext3_invalidatepage()
journal_invalidatepage()
journal_unmap_buffer()
__dispose_buffer()
__journal_unfile_buffer()
__journal_temp_unlink_buffer()
mark_buffer_dirty(); // PG_dirty set, incr. dirty pagesAnd then we end up with dirty pages being wrongly accounted.
As a result, in ecdfc9787fe527491baefc22dce8b2dbd5b2908d ("Resurrect
'try_to_free_buffers()' VM hackery") the changes to try_to_free_buffers
were reverted, so the original reason for the massive memory leak is
gone, and we can also revert the move of the call to cancel_dirty_page
from truncate_complete_page and get the accounting right again.I'm not sure if it matters, but opposed to the final check in
__remove_from_page_cache, this one also cares about the task io
accounting, so maybe we want to use this instead, although it's not
quite the clean fix either.Signed-off-by: Björn Steinbrink
Tested-by: Krzysztof Piotr Oledzki
Cc: Jan Kara
Cc: Nick Piggin
Cc: Peter Zijlstra
Cc: Thomas Osterried
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Simplify page cache zeroing of segments of pages through 3 functions
zero_user_segments(page, start1, end1, start2, end2)
Zeros two segments of the page. It takes the position where to
start and end the zeroing which avoids length calculations and
makes code clearer.zero_user_segment(page, start, end)
Same for a single segment.
zero_user(page, start, length)
Length variant for the case where we know the length.
We remove the zero_user_page macro. Issues:
1. Its a macro. Inline functions are preferable.
2. The KM_USER0 macro is only defined for HIGHMEM.
Having to treat this special case everywhere makes the
code needlessly complex. The parameter for zeroing is always
KM_USER0 except in one single case that we open code.Avoiding KM_USER0 makes a lot of code not having to be dealing
with the special casing for HIGHMEM anymore. Dealing with
kmap is only necessary for HIGHMEM configurations. In those
configurations we use KM_USER0 like we do for a series of other
functions defined in highmem.h.Since KM_USER0 is depends on HIGHMEM the existing zero_user_page
function could not be a macro. zero_user_* functions introduced
here can be be inline because that constant is not used when these
functions are called.Also extract the flushing of the caches to be outside of the kmap.
[akpm@linux-foundation.org: fix nfs and ntfs build]
[akpm@linux-foundation.org: fix ntfs build some more]
Signed-off-by: Christoph Lameter
Cc: Steven French
Cc: Michael Halcrow
Cc:
Cc: Steven Whitehouse
Cc: Trond Myklebust
Cc: "J. Bruce Fields"
Cc: Anton Altaparmakov
Cc: Mark Fasheh
Cc: David Chinner
Cc: Michael Halcrow
Cc: Steven French
Cc: Steven Whitehouse
Cc: Trond Myklebust
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
04 Feb, 2008
1 commit
-
Fix a typo in the comment for do_invalidatepage().
Signed-off-by: Fengguang Wu
Signed-off-by: Adrian Bunk
17 Oct, 2007
2 commits
-
mm.h doesn't use directly anything from mutex.h and backing-dev.h, so
remove them and add them back to files which need them.Cross-compile tested on many configs and archs.
Signed-off-by: Alexey Dobriyan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Count per BDI reclaimable pages; nr_reclaimable = nr_dirty + nr_unstable.
Signed-off-by: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
20 Jul, 2007
2 commits
-
Nonlinear mappings are (AFAIKS) simply a virtual memory concept that encodes
the virtual address -> file offset differently from linear mappings.->populate is a layering violation because the filesystem/pagecache code
should need to know anything about the virtual memory mapping. The hitch here
is that the ->nopage handler didn't pass down enough information (ie. pgoff).
But it is more logical to pass pgoff rather than have the ->nopage function
calculate it itself anyway (because that's a similar layering violation).Having the populate handler install the pte itself is likewise a nasty thing
to be doing.This patch introduces a new fault handler that replaces ->nopage and
->populate and (later) ->nopfn. Most of the old mechanism is still in place
so there is a lot of duplication and nice cleanups that can be removed if
everyone switches over.The rationale for doing this in the first place is that nonlinear mappings are
subject to the pagefault vs invalidate/truncate race too, and it seemed stupid
to duplicate the synchronisation logic rather than just consolidate the two.After this patch, MAP_NONBLOCK no longer sets up ptes for pages present in
pagecache. Seems like a fringe functionality anyway.NOPAGE_REFAULT is removed. This should be implemented with ->fault, and no
users have hit mainline yet.[akpm@linux-foundation.org: cleanup]
[randy.dunlap@oracle.com: doc. fixes for readahead]
[akpm@linux-foundation.org: build fix]
Signed-off-by: Nick Piggin
Signed-off-by: Randy Dunlap
Cc: Mark Fasheh
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Fix the race between invalidate_inode_pages and do_no_page.
Andrea Arcangeli identified a subtle race between invalidation of pages from
pagecache with userspace mappings, and do_no_page.The issue is that invalidation has to shoot down all mappings to the page,
before it can be discarded from the pagecache. Between shooting down ptes to
a particular page, and actually dropping the struct page from the pagecache,
do_no_page from any process might fault on that page and establish a new
mapping to the page just before it gets discarded from the pagecache.The most common case where such invalidation is used is in file truncation.
This case was catered for by doing a sort of open-coded seqlock between the
file's i_size, and its truncate_count.Truncation will decrease i_size, then increment truncate_count before
unmapping userspace pages; do_no_page will read truncate_count, then find the
page if it is within i_size, and then check truncate_count under the page
table lock and back out and retry if it had subsequently been changed (ptl
will serialise against unmapping, and ensure a potentially updated
truncate_count is actually visible).Complexity and documentation issues aside, the locking protocol fails in the
case where we would like to invalidate pagecache inside i_size. do_no_page
can come in anytime and filemap_nopage is not aware of the invalidation in
progress (as it is when it is outside i_size). The end result is that
dangling (->mapping == NULL) pages that appear to be from a particular file
may be mapped into userspace with nonsense data. Valid mappings to the same
place will see a different page.Andrea implemented two working fixes, one using a real seqlock, another using
a page->flags bit. He also proposed using the page lock in do_no_page, but
that was initially considered too heavyweight. However, it is not a global or
per-file lock, and the page cacheline is modified in do_no_page to increment
_count and _mapcount anyway, so a further modification should not be a large
performance hit. Scalability is not an issue.This patch implements this latter approach. ->nopage implementations return
with the page locked if it is possible for their underlying file to be
invalidated (in that case, they must set a special vm_flags bit to indicate
so). do_no_page only unlocks the page after setting up the mapping
completely. invalidation is excluded because it holds the page lock during
invalidation of each page (and ensures that the page is not mapped while
holding the lock).This also allows significant simplifications in do_no_page, because we have
the page locked in the right place in the pagecache from the start.Signed-off-by: Nick Piggin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
18 Jul, 2007
1 commit
-
It is a bug to set a page dirty if it is not uptodate unless it has
buffers. If the page has buffers, then the page may be dirty (some buffers
dirty) but not uptodate (some buffers not uptodate). The exception to this
rule is if the set_page_dirty caller is racing with truncate or invalidate.A buffer can not be set dirty if it is not uptodate.
If either of these situations occurs, it indicates there could be some data
loss problem. Some of these warnings could be a harmless one where the
page or buffer is set uptodate immediately after it is dirtied, however we
should fix those up, and enforce this ordering.Bring the order of operations for truncate into line with those of
invalidate. This will prevent a page from being able to go !uptodate while
we're holding the tree_lock, which is probably a good thing anyway.Signed-off-by: Nick Piggin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Jul, 2007
2 commits
-
invalidate_mapping_pages() can sometimes take a long time (millions of pages
to free). Long enough for the softlockup detector to trigger.We used to have a cond_resched() in there but I took it out because the
drop_caches code calls invalidate_mapping_pages() under inode_lock.The patch adds a nasty flag and puts the cond_resched() back.
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Fix the shrink_list name on some files under mm/ directory.
Signed-off-by: Anderson Briglia
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
