linux.git/mm/page-writeback.c, branch v6.7

mm: fix arithmetic for max_prop_frac when setting max_ratio

2023-12-29T19:06:47+00:00

Since now bdi->max_ratio is part per million, fix the wrong arithmetic for
max_prop_frac when setting max_ratio.  Otherwise the miscalculated
max_prop_frac will affect the incrementing of writeout completion count
when max_ratio is not 100%.

Link: https://lkml.kernel.org/r/20231219142508.86265-3-jefflexu@linux.alibaba.com
Fixes: efc3e6ad53ea ("mm: split off __bdi_set_max_ratio() function")
Signed-off-by: Jingbo Xu 
Cc: Joseph Qi 
Cc: Matthew Wilcox (Oracle) 
Cc: Stefan Roesch 
Signed-off-by: Andrew Morton

mm: fix arithmetic for bdi min_ratio

2023-12-29T19:06:47+00:00

Since now bdi->min_ratio is part per million, fix the wrong arithmetic. 
Otherwise it will fail with -EINVAL when setting a reasonable min_ratio,
as it tries to set min_ratio to (min_ratio * BDI_RATIO_SCALE) in
percentage unit, which exceeds 100% anyway.

    # cat /sys/class/bdi/253\:0/min_ratio
    0
    # cat /sys/class/bdi/253\:0/max_ratio
    100
    # echo 1 > /sys/class/bdi/253\:0/min_ratio
    -bash: echo: write error: Invalid argument

Link: https://lkml.kernel.org/r/20231219142508.86265-2-jefflexu@linux.alibaba.com
Fixes: 8021fb3232f2 ("mm: split off __bdi_set_min_ratio() function")
Signed-off-by: Jingbo Xu 
Reported-by: Joseph Qi 
Cc: Matthew Wilcox (Oracle) 
Cc: Stefan Roesch 
Signed-off-by: Andrew Morton

filemap: add a per-mapping stable writes flag

2023-11-20T14:05:18+00:00

folio_wait_stable waits for writeback to finish before modifying the
contents of a folio again, e.g. to support check summing of the data
in the block integrity code.

Currently this behavior is controlled by the SB_I_STABLE_WRITES flag
on the super_block, which means it is uniform for the entire file system.
This is wrong for the block device pseudofs which is shared by all
block devices, or file systems that can use multiple devices like XFS
witht the RT subvolume or btrfs (although btrfs currently reimplements
folio_wait_stable anyway).

Add a per-address_space AS_STABLE_WRITES flag to control the behavior
in a more fine grained way.  The existing SB_I_STABLE_WRITES is kept
to initialize AS_STABLE_WRITES to the existing default which covers
most cases.

Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20231025141020.192413-2-hch@lst.de
Tested-by: Ilya Dryomov 
Reviewed-by: Matthew Wilcox (Oracle) 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Christian Brauner

mm: use folio_xor_flags_has_waiters() in folio_end_writeback()

2023-10-18T21:34:17+00:00

Match how folio_unlock() works by combining the test for PG_waiters with
the clearing of PG_writeback.  This should have a small performance win,
and removes the last user of folio_wake().

Link: https://lkml.kernel.org/r/20231004165317.1061855-18-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Cc: Albert Ou 
Cc: Alexander Gordeev 
Cc: Andreas Dilger 
Cc: Christian Borntraeger 
Cc: Christophe Leroy 
Cc: Geert Uytterhoeven 
Cc: Heiko Carstens 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Michael Ellerman 
Cc: Nicholas Piggin 
Cc: Palmer Dabbelt 
Cc: Paul Walmsley 
Cc: Richard Henderson 
Cc: Sven Schnelle 
Cc: "Theodore Ts'o" 
Cc: Thomas Bogendoerfer 
Cc: Vasily Gorbik 
Signed-off-by: Andrew Morton

mm: make __end_folio_writeback() return void

2023-10-18T21:34:17+00:00

Rather than check the result of test-and-clear, just check that we have
the writeback bit set at the start.  This wouldn't catch every case, but
it's good enough (and enables the next patch).

Link: https://lkml.kernel.org/r/20231004165317.1061855-17-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Cc: Albert Ou 
Cc: Alexander Gordeev 
Cc: Andreas Dilger 
Cc: Christian Borntraeger 
Cc: Christophe Leroy 
Cc: Geert Uytterhoeven 
Cc: Heiko Carstens 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Michael Ellerman 
Cc: Nicholas Piggin 
Cc: Palmer Dabbelt 
Cc: Paul Walmsley 
Cc: Richard Henderson 
Cc: Sven Schnelle 
Cc: "Theodore Ts'o" 
Cc: Thomas Bogendoerfer 
Cc: Vasily Gorbik 
Signed-off-by: Andrew Morton

mm/writeback: update filemap_dirty_folio() comment

2023-10-04T17:32:32+00:00

Change to use new address space operation dirty_folio().

Link: https://lkml.kernel.org/r/20230917-trycontrib1-v1-1-db22630b8839@gmail.com
Fixes: 6f31a5a261db ("fs: Add aops->dirty_folio")
Signed-off-by: Jianguo Bau 
Cc: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton

mm: remove folio_account_redirty

2023-08-21T12:52:16+00:00

Fold folio_account_redirty into folio_redirty_for_writepage now
that all other users except for the also unused account_page_redirty
wrapper are gone.

Reviewed-by: Josef Bacik 
Reviewed-by: Matthew Wilcox (Oracle) 
Signed-off-by: Christoph Hellwig 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

writeback: account the number of pages written back

2023-07-08T16:29:30+00:00

nr_to_write is a count of pages, so we need to decrease it by the number
of pages in the folio we just wrote, not by 1.  Most callers specify
either LONG_MAX or 1, so are unaffected, but writeback_sb_inodes() might
end up writing 512x as many pages as it asked for.

Dave added:

: XFS is the only filesystem this would affect, right?  AFAIA, nothing
: else enables large folios and uses writeback through
: write_cache_pages() at this point...
: 
: In which case, I'd be surprised if much difference, if any, gets
: noticed by anyone.

Link: https://lkml.kernel.org/r/20230628185548.981888-1-willy@infradead.org
Fixes: 793917d997df ("mm/readahead: Add large folio readahead")
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Christoph Hellwig 
Cc: Jan Kara 
Cc: Dave Chinner 
Signed-off-by: Andrew Morton

mm: kill lock|unlock_page_memcg()

2023-06-19T23:19:33+00:00

Since commit c7c3dec1c9db ("mm: rmap: remove lock_page_memcg()"),
no more user, kill lock_page_memcg() and unlock_page_memcg().

Link: https://lkml.kernel.org/r/20230614143612.62575-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang 
Acked-by: Johannes Weiner 
Reviewed-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton

mm,jfs: move write_one_page/folio_write_one to jfs

2023-03-13T00:00:42+00:00

The last remaining user of folio_write_one through the write_one_page
wrapper is jfs, so move the functionality there and hard code the
call to metapage_writepage.

Note that the use of the pagecache by the JFS 'metapage' buffer cache
is a bit odd, and we could probably do without VM-level dirty tracking
at all, but that's a change for another time.

Signed-off-by: Christoph Hellwig 
Acked-by: Dave Kleikamp 
Signed-off-by: Al Viro