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| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2023-10-04 17:53:15 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-10-18 14:34:17 -0700 |
| commit | 0410cd844ed0af3db3cb510d877d62c66d26e5cc (patch) | |
| tree | d05e676a83fda128a26a87500f32b14adda6fdd9 /include/linux/page-flags.h | |
| parent | f12fb73b74fd23ca33e3f95fb996f295eeae1da7 (diff) | |
| download | linux-0410cd844ed0af3db3cb510d877d62c66d26e5cc.tar.gz linux-0410cd844ed0af3db3cb510d877d62c66d26e5cc.tar.bz2 linux-0410cd844ed0af3db3cb510d877d62c66d26e5cc.zip | |
mm: add folio_xor_flags_has_waiters()
Optimise folio_end_read() by setting the uptodate bit at the same time we
clear the unlock bit. This saves at least one memory barrier and one
write-after-write hazard.
Link: https://lkml.kernel.org/r/20231004165317.1061855-16-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/page-flags.h')
| -rw-r--r-- | include/linux/page-flags.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 5c02720c53a5..a88e64acebfe 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -693,6 +693,25 @@ TESTPAGEFLAG_FALSE(Ksm, ksm) u64 stable_page_flags(struct page *page); /** + * folio_xor_flags_has_waiters - Change some folio flags. + * @folio: The folio. + * @mask: Bits set in this word will be changed. + * + * This must only be used for flags which are changed with the folio + * lock held. For example, it is unsafe to use for PG_dirty as that + * can be set without the folio lock held. It can also only be used + * on flags which are in the range 0-6 as some of the implementations + * only affect those bits. + * + * Return: Whether there are tasks waiting on the folio. + */ +static inline bool folio_xor_flags_has_waiters(struct folio *folio, + unsigned long mask) +{ + return xor_unlock_is_negative_byte(mask, folio_flags(folio, 0)); +} + +/** * folio_test_uptodate - Is this folio up to date? * @folio: The folio. * |