<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/fs/f2fs/node.c, branch v5.18</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>f2fs: Get the superblock from the mapping instead of the page</title>
<updated>2022-04-01T18:40:44+00:00</updated>
<author>
<name>Matthew Wilcox (Oracle)</name>
<email>willy@infradead.org</email>
</author>
<published>2022-03-29T20:27:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=29c87793eb3c6f78f215f85be863e5415e263e43'/>
<id>29c87793eb3c6f78f215f85be863e5415e263e43</id>
<content type='text'>
It's slightly more efficient to go directly from the mapping to the
superblock than to go from the page.  Now that these routines have
the mapping passed to them, there's no reason not to use it.

Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Acked-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
It's slightly more efficient to go directly from the mapping to the
superblock than to go from the page.  Now that these routines have
the mapping passed to them, there's no reason not to use it.

Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Acked-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'folio-5.18b' of git://git.infradead.org/users/willy/pagecache</title>
<updated>2022-03-23T01:26:56+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-03-23T01:26:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6b1f86f8e9c7f9de7ca1cb987b2cf25e99b1ae3a'/>
<id>6b1f86f8e9c7f9de7ca1cb987b2cf25e99b1ae3a</id>
<content type='text'>
Pull filesystem folio updates from Matthew Wilcox:
 "Primarily this series converts some of the address_space operations to
  take a folio instead of a page.

  Notably:

   - a_ops-&gt;is_partially_uptodate() takes a folio instead of a page and
     changes the type of the 'from' and 'count' arguments to make it
     obvious they're bytes.

   - a_ops-&gt;invalidatepage() becomes -&gt;invalidate_folio() and has a
     similar type change.

   - a_ops-&gt;launder_page() becomes -&gt;launder_folio()

   - a_ops-&gt;set_page_dirty() becomes -&gt;dirty_folio() and adds the
     address_space as an argument.

  There are a couple of other misc changes up front that weren't worth
  separating into their own pull request"

* tag 'folio-5.18b' of git://git.infradead.org/users/willy/pagecache: (53 commits)
  fs: Remove aops -&gt;set_page_dirty
  fb_defio: Use noop_dirty_folio()
  fs: Convert __set_page_dirty_no_writeback to noop_dirty_folio
  fs: Convert __set_page_dirty_buffers to block_dirty_folio
  nilfs: Convert nilfs_set_page_dirty() to nilfs_dirty_folio()
  mm: Convert swap_set_page_dirty() to swap_dirty_folio()
  ubifs: Convert ubifs_set_page_dirty to ubifs_dirty_folio
  f2fs: Convert f2fs_set_node_page_dirty to f2fs_dirty_node_folio
  f2fs: Convert f2fs_set_data_page_dirty to f2fs_dirty_data_folio
  f2fs: Convert f2fs_set_meta_page_dirty to f2fs_dirty_meta_folio
  afs: Convert afs_dir_set_page_dirty() to afs_dir_dirty_folio()
  btrfs: Convert extent_range_redirty_for_io() to use folios
  fs: Convert trivial uses of __set_page_dirty_nobuffers to filemap_dirty_folio
  btrfs: Convert from set_page_dirty to dirty_folio
  fscache: Convert fscache_set_page_dirty() to fscache_dirty_folio()
  fs: Add aops-&gt;dirty_folio
  fs: Remove aops-&gt;launder_page
  orangefs: Convert launder_page to launder_folio
  nfs: Convert from launder_page to launder_folio
  fuse: Convert from launder_page to launder_folio
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull filesystem folio updates from Matthew Wilcox:
 "Primarily this series converts some of the address_space operations to
  take a folio instead of a page.

  Notably:

   - a_ops-&gt;is_partially_uptodate() takes a folio instead of a page and
     changes the type of the 'from' and 'count' arguments to make it
     obvious they're bytes.

   - a_ops-&gt;invalidatepage() becomes -&gt;invalidate_folio() and has a
     similar type change.

   - a_ops-&gt;launder_page() becomes -&gt;launder_folio()

   - a_ops-&gt;set_page_dirty() becomes -&gt;dirty_folio() and adds the
     address_space as an argument.

  There are a couple of other misc changes up front that weren't worth
  separating into their own pull request"

* tag 'folio-5.18b' of git://git.infradead.org/users/willy/pagecache: (53 commits)
  fs: Remove aops -&gt;set_page_dirty
  fb_defio: Use noop_dirty_folio()
  fs: Convert __set_page_dirty_no_writeback to noop_dirty_folio
  fs: Convert __set_page_dirty_buffers to block_dirty_folio
  nilfs: Convert nilfs_set_page_dirty() to nilfs_dirty_folio()
  mm: Convert swap_set_page_dirty() to swap_dirty_folio()
  ubifs: Convert ubifs_set_page_dirty to ubifs_dirty_folio
  f2fs: Convert f2fs_set_node_page_dirty to f2fs_dirty_node_folio
  f2fs: Convert f2fs_set_data_page_dirty to f2fs_dirty_data_folio
  f2fs: Convert f2fs_set_meta_page_dirty to f2fs_dirty_meta_folio
  afs: Convert afs_dir_set_page_dirty() to afs_dir_dirty_folio()
  btrfs: Convert extent_range_redirty_for_io() to use folios
  fs: Convert trivial uses of __set_page_dirty_nobuffers to filemap_dirty_folio
  btrfs: Convert from set_page_dirty to dirty_folio
  fscache: Convert fscache_set_page_dirty() to fscache_dirty_folio()
  fs: Add aops-&gt;dirty_folio
  fs: Remove aops-&gt;launder_page
  orangefs: Convert launder_page to launder_folio
  nfs: Convert from launder_page to launder_folio
  fuse: Convert from launder_page to launder_folio
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>f2fs: Convert f2fs_set_node_page_dirty to f2fs_dirty_node_folio</title>
<updated>2022-03-15T12:34:38+00:00</updated>
<author>
<name>Matthew Wilcox (Oracle)</name>
<email>willy@infradead.org</email>
</author>
<published>2022-02-09T20:22:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cbc975b182a073d3bc72b487e47e741a05c19493'/>
<id>cbc975b182a073d3bc72b487e47e741a05c19493</id>
<content type='text'>
Removes a call to __set_page_dirty_nobuffers().

Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Tested-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Acked-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Tested-by: Mike Marshall &lt;hubcap@omnibond.com&gt; # orangefs
Tested-by: David Howells &lt;dhowells@redhat.com&gt; # afs
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Removes a call to __set_page_dirty_nobuffers().

Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Tested-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Acked-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Tested-by: Mike Marshall &lt;hubcap@omnibond.com&gt; # orangefs
Tested-by: David Howells &lt;dhowells@redhat.com&gt; # afs
</pre>
</div>
</content>
</entry>
<entry>
<title>f2fs: Convert invalidatepage to invalidate_folio</title>
<updated>2022-03-15T12:23:30+00:00</updated>
<author>
<name>Matthew Wilcox (Oracle)</name>
<email>willy@infradead.org</email>
</author>
<published>2022-02-09T20:21:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=915039967342758ea1c26d99dd5ca2bef51ee382'/>
<id>915039967342758ea1c26d99dd5ca2bef51ee382</id>
<content type='text'>
This is a minimal change which just accepts the new arguments and passes
the single struct page to the functions which do the work.  There is
very little progress here toards making f2fs support large folios.

Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Tested-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Acked-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Tested-by: Mike Marshall &lt;hubcap@omnibond.com&gt; # orangefs
Tested-by: David Howells &lt;dhowells@redhat.com&gt; # afs
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This is a minimal change which just accepts the new arguments and passes
the single struct page to the functions which do the work.  There is
very little progress here toards making f2fs support large folios.

Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Tested-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Acked-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Tested-by: Mike Marshall &lt;hubcap@omnibond.com&gt; # orangefs
Tested-by: David Howells &lt;dhowells@redhat.com&gt; # afs
</pre>
</div>
</content>
</entry>
<entry>
<title>f2fs: fix to avoid potential deadlock</title>
<updated>2022-03-03T21:30:48+00:00</updated>
<author>
<name>Chao Yu</name>
<email>chao@kernel.org</email>
</author>
<published>2022-01-27T05:44:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=344150999b7fc88502a65bbb147a47503eca2033'/>
<id>344150999b7fc88502a65bbb147a47503eca2033</id>
<content type='text'>
Quoted from Jing Xia's report, there is a potential deadlock may happen
between kworker and checkpoint as below:

[T:writeback]				[T:checkpoint]
- wb_writeback
 - blk_start_plug
bio contains NodeA was plugged in writeback threads
					- do_writepages  -- sync write inodeB, inc wb_sync_req[DATA]
					 - f2fs_write_data_pages
					  - f2fs_write_single_data_page -- write last dirty page
					   - f2fs_do_write_data_page
					    - set_page_writeback  -- clear page dirty flag and
					    PAGECACHE_TAG_DIRTY tag in radix tree
					    - f2fs_outplace_write_data
					     - f2fs_update_data_blkaddr
					      - f2fs_wait_on_page_writeback -- wait NodeA to writeback here
					   - inode_dec_dirty_pages
 - writeback_sb_inodes
  - writeback_single_inode
   - do_writepages
    - f2fs_write_data_pages -- skip writepages due to wb_sync_req[DATA]
     - wbc-&gt;pages_skipped += get_dirty_pages() -- PAGECACHE_TAG_DIRTY is not set but get_dirty_pages() returns one
  - requeue_inode -- requeue inode to wb-&gt;b_dirty queue due to non-zero.pages_skipped
 - blk_finish_plug

Let's try to avoid deadlock condition by forcing unplugging previous bio via
blk_finish_plug(current-&gt;plug) once we'v skipped writeback in writepages()
due to valid sbi-&gt;wb_sync_req[DATA/NODE].

Fixes: 687de7f1010c ("f2fs: avoid IO split due to mixed WB_SYNC_ALL and WB_SYNC_NONE")
Signed-off-by: Zhiguo Niu &lt;zhiguo.niu@unisoc.com&gt;
Signed-off-by: Jing Xia &lt;jing.xia@unisoc.com&gt;
Signed-off-by: Chao Yu &lt;chao@kernel.org&gt;
Signed-off-by: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Quoted from Jing Xia's report, there is a potential deadlock may happen
between kworker and checkpoint as below:

[T:writeback]				[T:checkpoint]
- wb_writeback
 - blk_start_plug
bio contains NodeA was plugged in writeback threads
					- do_writepages  -- sync write inodeB, inc wb_sync_req[DATA]
					 - f2fs_write_data_pages
					  - f2fs_write_single_data_page -- write last dirty page
					   - f2fs_do_write_data_page
					    - set_page_writeback  -- clear page dirty flag and
					    PAGECACHE_TAG_DIRTY tag in radix tree
					    - f2fs_outplace_write_data
					     - f2fs_update_data_blkaddr
					      - f2fs_wait_on_page_writeback -- wait NodeA to writeback here
					   - inode_dec_dirty_pages
 - writeback_sb_inodes
  - writeback_single_inode
   - do_writepages
    - f2fs_write_data_pages -- skip writepages due to wb_sync_req[DATA]
     - wbc-&gt;pages_skipped += get_dirty_pages() -- PAGECACHE_TAG_DIRTY is not set but get_dirty_pages() returns one
  - requeue_inode -- requeue inode to wb-&gt;b_dirty queue due to non-zero.pages_skipped
 - blk_finish_plug

Let's try to avoid deadlock condition by forcing unplugging previous bio via
blk_finish_plug(current-&gt;plug) once we'v skipped writeback in writepages()
due to valid sbi-&gt;wb_sync_req[DATA/NODE].

Fixes: 687de7f1010c ("f2fs: avoid IO split due to mixed WB_SYNC_ALL and WB_SYNC_NONE")
Signed-off-by: Zhiguo Niu &lt;zhiguo.niu@unisoc.com&gt;
Signed-off-by: Jing Xia &lt;jing.xia@unisoc.com&gt;
Signed-off-by: Chao Yu &lt;chao@kernel.org&gt;
Signed-off-by: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>f2fs: add a way to limit roll forward recovery time</title>
<updated>2022-02-12T13:58:18+00:00</updated>
<author>
<name>Jaegeuk Kim</name>
<email>jaegeuk@kernel.org</email>
</author>
<published>2022-01-27T21:31:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=47c8ebcce85ed7113e9e3e3f1d8c6374fa87848e'/>
<id>47c8ebcce85ed7113e9e3e3f1d8c6374fa87848e</id>
<content type='text'>
This adds a sysfs entry to call checkpoint during fsync() in order to avoid
long elapsed time to run roll-forward recovery when booting the device.
Default value doesn't enforce the limitation which is same as before.

Reviewed-by: Chao Yu &lt;chao@kernel.org&gt;
Signed-off-by: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This adds a sysfs entry to call checkpoint during fsync() in order to avoid
long elapsed time to run roll-forward recovery when booting the device.
Default value doesn't enforce the limitation which is same as before.

Reviewed-by: Chao Yu &lt;chao@kernel.org&gt;
Signed-off-by: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>f2fs: move f2fs to use reader-unfair rwsems</title>
<updated>2022-01-25T01:40:04+00:00</updated>
<author>
<name>Tim Murray</name>
<email>timmurray@google.com</email>
</author>
<published>2022-01-07T20:48:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e4544b63a7ee49e7fbebf35ece0a6acd3b9617ae'/>
<id>e4544b63a7ee49e7fbebf35ece0a6acd3b9617ae</id>
<content type='text'>
f2fs rw_semaphores work better if writers can starve readers,
especially for the checkpoint thread, because writers are strictly
more important than reader threads. This prevents significant priority
inversion between low-priority readers that blocked while trying to
acquire the read lock and a second acquisition of the write lock that
might be blocking high priority work.

Signed-off-by: Tim Murray &lt;timmurray@google.com&gt;
Signed-off-by: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
f2fs rw_semaphores work better if writers can starve readers,
especially for the checkpoint thread, because writers are strictly
more important than reader threads. This prevents significant priority
inversion between low-priority readers that blocked while trying to
acquire the read lock and a second acquisition of the write lock that
might be blocking high priority work.

Signed-off-by: Tim Murray &lt;timmurray@google.com&gt;
Signed-off-by: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'f2fs-for-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs</title>
<updated>2022-01-19T09:50:20+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-01-19T09:50:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1d1df41c5a33359a00e919d54eaebfb789711fdc'/>
<id>1d1df41c5a33359a00e919d54eaebfb789711fdc</id>
<content type='text'>
Pull f2fs updates from Jaegeuk Kim:
 "In this round, we've tried to address some performance issues in
  f2fs_checkpoint and direct IO flows. Also, there was a work to enhance
  the page cache management used for compression. Other than them, we've
  done typical work including sysfs, code clean-ups, tracepoint, sanity
  check, in addition to bug fixes on corner cases.

  Enhancements:
   - use iomap for direct IO
   - try to avoid lock contention to improve f2fs_ckpt speed
   - avoid unnecessary memory allocation in compression flow
   - POSIX_FADV_DONTNEED drops the page cache containing compression
     pages
   - add some sysfs entries (gc_urgent_high_remaining, pending_discard)

  Bug fixes:
   - try not to expose unwritten blocks to user by DIO (this was added
     to avoid merge conflict; another patch is coming to address other
     missing case)
   - relax minor error condition for file pinning feature used in
     Android OTA
   - fix potential deadlock case in compression flow
   - should not truncate any block on pinned file

  In addition, we've done some code clean-ups and tracepoint/sanity
  check improvement"

* tag 'f2fs-for-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (29 commits)
  f2fs: do not allow partial truncation on pinned file
  f2fs: remove redunant invalidate compress pages
  f2fs: Simplify bool conversion
  f2fs: don't drop compressed page cache in .{invalidate,release}page
  f2fs: fix to reserve space for IO align feature
  f2fs: fix to check available space of CP area correctly in update_ckpt_flags()
  f2fs: support fault injection to f2fs_trylock_op()
  f2fs: clean up __find_inline_xattr() with __find_xattr()
  f2fs: fix to do sanity check on last xattr entry in __f2fs_setxattr()
  f2fs: do not bother checkpoint by f2fs_get_node_info
  f2fs: avoid down_write on nat_tree_lock during checkpoint
  f2fs: compress: fix potential deadlock of compress file
  f2fs: avoid EINVAL by SBI_NEED_FSCK when pinning a file
  f2fs: add gc_urgent_high_remaining sysfs node
  f2fs: fix to do sanity check in is_alive()
  f2fs: fix to avoid panic in is_alive() if metadata is inconsistent
  f2fs: fix to do sanity check on inode type during garbage collection
  f2fs: avoid duplicate call of mark_inode_dirty
  f2fs: show number of pending discard commands
  f2fs: support POSIX_FADV_DONTNEED drop compressed page cache
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull f2fs updates from Jaegeuk Kim:
 "In this round, we've tried to address some performance issues in
  f2fs_checkpoint and direct IO flows. Also, there was a work to enhance
  the page cache management used for compression. Other than them, we've
  done typical work including sysfs, code clean-ups, tracepoint, sanity
  check, in addition to bug fixes on corner cases.

  Enhancements:
   - use iomap for direct IO
   - try to avoid lock contention to improve f2fs_ckpt speed
   - avoid unnecessary memory allocation in compression flow
   - POSIX_FADV_DONTNEED drops the page cache containing compression
     pages
   - add some sysfs entries (gc_urgent_high_remaining, pending_discard)

  Bug fixes:
   - try not to expose unwritten blocks to user by DIO (this was added
     to avoid merge conflict; another patch is coming to address other
     missing case)
   - relax minor error condition for file pinning feature used in
     Android OTA
   - fix potential deadlock case in compression flow
   - should not truncate any block on pinned file

  In addition, we've done some code clean-ups and tracepoint/sanity
  check improvement"

* tag 'f2fs-for-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (29 commits)
  f2fs: do not allow partial truncation on pinned file
  f2fs: remove redunant invalidate compress pages
  f2fs: Simplify bool conversion
  f2fs: don't drop compressed page cache in .{invalidate,release}page
  f2fs: fix to reserve space for IO align feature
  f2fs: fix to check available space of CP area correctly in update_ckpt_flags()
  f2fs: support fault injection to f2fs_trylock_op()
  f2fs: clean up __find_inline_xattr() with __find_xattr()
  f2fs: fix to do sanity check on last xattr entry in __f2fs_setxattr()
  f2fs: do not bother checkpoint by f2fs_get_node_info
  f2fs: avoid down_write on nat_tree_lock during checkpoint
  f2fs: compress: fix potential deadlock of compress file
  f2fs: avoid EINVAL by SBI_NEED_FSCK when pinning a file
  f2fs: add gc_urgent_high_remaining sysfs node
  f2fs: fix to do sanity check in is_alive()
  f2fs: fix to avoid panic in is_alive() if metadata is inconsistent
  f2fs: fix to do sanity check on inode type during garbage collection
  f2fs: avoid duplicate call of mark_inode_dirty
  f2fs: show number of pending discard commands
  f2fs: support POSIX_FADV_DONTNEED drop compressed page cache
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: introduce memalloc_retry_wait()</title>
<updated>2022-01-15T14:30:29+00:00</updated>
<author>
<name>NeilBrown</name>
<email>neilb@suse.de</email>
</author>
<published>2022-01-14T22:07:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4034247a0d6ab281ba3293798ce67af494d86129'/>
<id>4034247a0d6ab281ba3293798ce67af494d86129</id>
<content type='text'>
Various places in the kernel - largely in filesystems - respond to a
memory allocation failure by looping around and re-trying.  Some of
these cannot conveniently use __GFP_NOFAIL, for reasons such as:

 - a GFP_ATOMIC allocation, which __GFP_NOFAIL doesn't work on
 - a need to check for the process being signalled between failures
 - the possibility that other recovery actions could be performed
 - the allocation is quite deep in support code, and passing down an
   extra flag to say if __GFP_NOFAIL is wanted would be clumsy.

Many of these currently use congestion_wait() which (in almost all
cases) simply waits the given timeout - congestion isn't tracked for
most devices.

It isn't clear what the best delay is for loops, but it is clear that
the various filesystems shouldn't be responsible for choosing a timeout.

This patch introduces memalloc_retry_wait() with takes on that
responsibility.  Code that wants to retry a memory allocation can call
this function passing the GFP flags that were used.  It will wait
however is appropriate.

For now, it only considers __GFP_NORETRY and whatever
gfpflags_allow_blocking() tests.  If blocking is allowed without
__GFP_NORETRY, then alloc_page either made some reclaim progress, or
waited for a while, before failing.  So there is no need for much
further waiting.  memalloc_retry_wait() will wait until the current
jiffie ends.  If this condition is not met, then alloc_page() won't have
waited much if at all.  In that case memalloc_retry_wait() waits about
200ms.  This is the delay that most current loops uses.

linux/sched/mm.h needs to be included in some files now,
but linux/backing-dev.h does not.

Link: https://lkml.kernel.org/r/163754371968.13692.1277530886009912421@noble.neil.brown.name
Signed-off-by: NeilBrown &lt;neilb@suse.de&gt;
Cc: Dave Chinner &lt;david@fromorbit.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Cc: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
Cc: Chao Yu &lt;chao@kernel.org&gt;
Cc: Darrick J. Wong &lt;djwong@kernel.org&gt;
Cc: Chuck Lever &lt;chuck.lever@oracle.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Various places in the kernel - largely in filesystems - respond to a
memory allocation failure by looping around and re-trying.  Some of
these cannot conveniently use __GFP_NOFAIL, for reasons such as:

 - a GFP_ATOMIC allocation, which __GFP_NOFAIL doesn't work on
 - a need to check for the process being signalled between failures
 - the possibility that other recovery actions could be performed
 - the allocation is quite deep in support code, and passing down an
   extra flag to say if __GFP_NOFAIL is wanted would be clumsy.

Many of these currently use congestion_wait() which (in almost all
cases) simply waits the given timeout - congestion isn't tracked for
most devices.

It isn't clear what the best delay is for loops, but it is clear that
the various filesystems shouldn't be responsible for choosing a timeout.

This patch introduces memalloc_retry_wait() with takes on that
responsibility.  Code that wants to retry a memory allocation can call
this function passing the GFP flags that were used.  It will wait
however is appropriate.

For now, it only considers __GFP_NORETRY and whatever
gfpflags_allow_blocking() tests.  If blocking is allowed without
__GFP_NORETRY, then alloc_page either made some reclaim progress, or
waited for a while, before failing.  So there is no need for much
further waiting.  memalloc_retry_wait() will wait until the current
jiffie ends.  If this condition is not met, then alloc_page() won't have
waited much if at all.  In that case memalloc_retry_wait() waits about
200ms.  This is the delay that most current loops uses.

linux/sched/mm.h needs to be included in some files now,
but linux/backing-dev.h does not.

Link: https://lkml.kernel.org/r/163754371968.13692.1277530886009912421@noble.neil.brown.name
Signed-off-by: NeilBrown &lt;neilb@suse.de&gt;
Cc: Dave Chinner &lt;david@fromorbit.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Cc: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
Cc: Chao Yu &lt;chao@kernel.org&gt;
Cc: Darrick J. Wong &lt;djwong@kernel.org&gt;
Cc: Chuck Lever &lt;chuck.lever@oracle.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>f2fs: do not bother checkpoint by f2fs_get_node_info</title>
<updated>2022-01-04T21:20:49+00:00</updated>
<author>
<name>Jaegeuk Kim</name>
<email>jaegeuk@kernel.org</email>
</author>
<published>2021-12-13T22:16:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a9419b63bf414775e8aeee95d8c4a5e0df690748'/>
<id>a9419b63bf414775e8aeee95d8c4a5e0df690748</id>
<content type='text'>
This patch tries to mitigate lock contention between f2fs_write_checkpoint and
f2fs_get_node_info along with nat_tree_lock.

The idea is, if checkpoint is currently running, other threads that try to grab
nat_tree_lock would be better to wait for checkpoint.

Reviewed-by: Chao Yu &lt;chao@kernel.org&gt;
Signed-off-by: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch tries to mitigate lock contention between f2fs_write_checkpoint and
f2fs_get_node_info along with nat_tree_lock.

The idea is, if checkpoint is currently running, other threads that try to grab
nat_tree_lock would be better to wait for checkpoint.

Reviewed-by: Chao Yu &lt;chao@kernel.org&gt;
Signed-off-by: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
