linux-toradex.git/mm/truncate.c, branch PD13.2.2

mm: fix assertion mapping->nrpages == 0 in end_writeback()

2011-06-28T01:00:13+00:00

Under heavy memory and filesystem load, users observe the assertion
mapping->nrpages == 0 in end_writeback() trigger.  This can be caused by
page reclaim reclaiming the last page from a mapping in the following
race:

	CPU0				CPU1
  ...
  shrink_page_list()
    __remove_mapping()
      __delete_from_page_cache()
        radix_tree_delete()
					evict_inode()
					  truncate_inode_pages()
					    truncate_inode_pages_range()
					      pagevec_lookup() - finds nothing
					  end_writeback()
					    mapping->nrpages != 0 -> BUG
        page->mapping = NULL
        mapping->nrpages--

Fix the problem by doing a reliable check of mapping->nrpages under
mapping->tree_lock in end_writeback().

Analyzed by Jay , lost in LKML, and dug out
by Miklos Szeredi .

Cc: Jay 
Cc: Miklos Szeredi 
Signed-off-by: Jan Kara 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tmpfs: take control of its truncate_range

2011-06-28T01:00:12+00:00

2.6.35's new truncate convention gave tmpfs the opportunity to control
its file truncation, no longer enforced from outside by vmtruncate().
We shall want to build upon that, to handle pagecache and swap together.

Slightly redefine the ->truncate_range interface: let it now be called
between the unmap_mapping_range()s, with the filesystem responsible for
doing the truncate_inode_pages_range() from it - just as the filesystem
is nowadays responsible for doing that from its ->setattr.

Let's rename shmem_notify_change() to shmem_setattr().  Instead of
calling the generic truncate_setsize(), bring that code in so we can
call shmem_truncate_range() - which will later be updated to perform its
own variant of truncate_inode_pages_range().

Remove the punch_hole unmap_mapping_range() from shmem_truncate_range():
now that the COW's unmap_mapping_range() comes after ->truncate_range,
there is no need to call it a third time.

Export shmem_truncate_range() and add it to the list in shmem_fs.h, so
that i915_gem_object_truncate() can call it explicitly in future; get
this patch in first, then update drm/i915 once this is available (until
then, i915 will just be doing the truncate_inode_pages() twice).

Though introduced five years ago, no other filesystem is implementing
->truncate_range, and its only other user is madvise(,,MADV_REMOVE): we
expect to convert it to fallocate(,FALLOC_FL_PUNCH_HOLE,,) shortly,
whereupon ->truncate_range can be removed from inode_operations -
shmem_truncate_range() will help i915 across that transition too.

Signed-off-by: Hugh Dickins 
Cc: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: move vmtruncate_range to truncate.c

2011-06-28T01:00:12+00:00

You would expect to find vmtruncate_range() next to vmtruncate() in
mm/truncate.c: move it there.

Signed-off-by: Hugh Dickins 
Acked-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/fs: add hooks to support cleancache

2011-05-26T16:01:43+00:00

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

mm: deactivate invalidated pages

2011-03-23T00:44:03+00:00

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

mm: change __remove_from_page_cache()

2011-03-23T00:44:02+00:00

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

mm: truncate: change remove_from_page_cache

2011-03-23T00:44:02+00:00

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

memcg: more mem_cgroup_uncharge() batching

2011-02-25T23:07:37+00:00

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

mm: fix truncate_setsize() comment

2011-01-21T01:02:06+00:00

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

Call the filesystem back whenever a page is removed from the page cache

2010-12-02T14:55:21+00:00

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