Hello, Yang. 2022년 8월 12일 (금) 오전 7:10, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>님이 작성: > > > The patch titled > Subject: filemap: make the accounting of thrashing more consistent > has been added to the -mm mm-unstable branch. Its filename is > filemap-make-the-accounting-of-thrashing-more-consistent.patch > > This patch will shortly appear at > https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/filemap-make-the-accounting-of-thrashing-more-consistent.patch > > This patch will later appear in the mm-unstable branch at > git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm > > Before you just go and hit "reply", please: > a) Consider who else should be cc'ed > b) Prefer to cc a suitable mailing list as well > c) Ideally: find the original patch on the mailing list and do a > reply-to-all to that, adding suitable additional cc's > > *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** > > The -mm tree is included into linux-next via the mm-everything > branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm > and is updated there every 2-3 working days > > ------------------------------------------------------ > From: Yang Yang <yang.yang29@xxxxxxxxxx> > Subject: filemap: make the accounting of thrashing more consistent > Date: Fri, 5 Aug 2022 03:38:39 +0000 > > Once upon a time, we only support accounting thrashing of page cache. > Then Joonsoo introduced workingset detection for anonymous pages and we > gained the ability to account thrashing of them[1]. > > So let delayacct account both the thrashing of page cache and anonymous > pages, this could make the codes more consistent and simpler. > > [1] commit aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU") > > Link: https://lkml.kernel.org/r/20220805033838.1714674-1-yang.yang29@xxxxxxxxxx > Signed-off-by: Yang Yang <yang.yang29@xxxxxxxxxx> > Signed-off-by: CGEL ZTE <cgel.zte@xxxxxxxxx> > Cc: Balbir Singh <bsingharora@xxxxxxxxx> > Cc: Jonathan Corbet <corbet@xxxxxxx> > Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> > Cc: Yang Yang <yang.yang29@xxxxxxxxxx> > Cc: David Hildenbrand <david@xxxxxxxxxx> > Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > --- > > Documentation/accounting/delay-accounting.rst | 2 - > mm/filemap.c | 18 +++------------- > 2 files changed, 5 insertions(+), 15 deletions(-) > > --- a/Documentation/accounting/delay-accounting.rst~filemap-make-the-accounting-of-thrashing-more-consistent > +++ a/Documentation/accounting/delay-accounting.rst > @@ -13,7 +13,7 @@ a) waiting for a CPU (while being runnab > b) completion of synchronous block I/O initiated by the task > c) swapping in pages > d) memory reclaim > -e) thrashing page cache > +e) thrashing > f) direct compact > g) write-protect copy > > --- a/mm/filemap.c~filemap-make-the-accounting-of-thrashing-more-consistent > +++ a/mm/filemap.c > @@ -1221,15 +1221,11 @@ static inline int folio_wait_bit_common( > struct wait_page_queue wait_page; > wait_queue_entry_t *wait = &wait_page.wait; > bool thrashing = false; > - bool delayacct = false; > unsigned long pflags; > > if (bit_nr == PG_locked && > !folio_test_uptodate(folio) && folio_test_workingset(folio)) { > - if (!folio_test_swapbacked(folio)) { > - delayacct_thrashing_start(); > - delayacct = true; > - } > + delayacct_thrashing_start(); > psi_memstall_enter(&pflags); > thrashing = true; > } I think that a better place to measure swap thrashing is swap_readpage(). For some cases, like a zram, swap_readpage() is called directly rather than loading the page onto the swap cache. Your code would miss that case. Thanks.
