Messages in this thread |  | | | Date | Sat, 03 Mar 2012 12:27:39 +0400 | | From | Konstantin Khlebnikov <> | | Subject | Re: [PATCH 3/7] mm: rework __isolate_lru_page() file/anon filter |
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Hugh Dickins wrote: > On Wed, 29 Feb 2012, Konstantin Khlebnikov wrote: > >> This patch adds file/anon filter bits into isolate_mode_t, >> this allows to simplify checks in __isolate_lru_page(). >> >> Signed-off-by: Konstantin Khlebnikov<khlebnikov@openvz.org> > > Almost-Acked-by: Hugh Dickins<hughd@google.com> > > with one whitespace nit, and one functional addition requested. > > I'm perfectly happy with your :?s myself, but some people do dislike > them. I'm happy with the switch alternative if it's as efficient: > something that surprised me very much when trying to get convincing > performance numbers for per-memcg per-zone lru_lock at home... > > ... __isolate_lru_page() featured astonishly high on the perf report > of streaming from files on ext4 on /dev/ram0 to /dev/null, coming > immediately below the obvious zeroing and copying: okay, the zeroing > and copying were around 30% each, and __isolate_lru_page() down around > 2% or below, but even so it seemed very odd that it should feature so > high, and any optimizations to it very welcome - unless it was purely > some bogus result.
Actually ANON/FILE ACTIVE/INACTIVE checks does not required at non-lumpy reclaim (all pages are picked from right lru list) and compaction (it does not care). But seems like removing these two bit-checks cannot give noticeable performance gain.
This patch can be postponed. It does not so important and it does not share context with other patches in this set.
> >> --- >> include/linux/mmzone.h | 4 ++++ >> include/linux/swap.h | 2 +- >> mm/compaction.c | 5 +++-- >> mm/vmscan.c | 27 +++++++++++++-------------- >> 4 files changed, 21 insertions(+), 17 deletions(-) >> >> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h >> index eff4918..2fed935 100644 >> --- a/include/linux/mmzone.h >> +++ b/include/linux/mmzone.h >> @@ -193,6 +193,10 @@ struct lruvec { >> #define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x8) >> /* Isolate for asynchronous migration */ >> #define ISOLATE_ASYNC_MIGRATE ((__force isolate_mode_t)0x10) >> +/* Isolate swap-backed pages */ >> +#define ISOLATE_ANON ((__force isolate_mode_t)0x20) >> +/* Isolate file-backed pages */ >> +#define ISOLATE_FILE ((__force isolate_mode_t)0x40) > > From the patch you can see that the #defines above yours used a > space where you have used a tab: better to use a space as above. > >> @@ -375,7 +376,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, >> mode |= ISOLATE_ASYNC_MIGRATE; >> >> /* Try isolate the page */ >> - if (__isolate_lru_page(page, mode, 0) != 0) >> + if (__isolate_lru_page(page, mode) != 0) >> continue; > > I thought you were missing something there, but no, that's rather > the case you are simplifying. However... > >> diff --git a/mm/vmscan.c b/mm/vmscan.c >> index af6cfe7..1b70338 100644 >> --- a/mm/vmscan.c >> +++ b/mm/vmscan.c >> @@ -1520,6 +1511,10 @@ shrink_inactive_list(unsigned long nr_to_scan, struct mem_cgroup_zone *mz, >> isolate_mode |= ISOLATE_UNMAPPED; >> if (!sc->may_writepage) >> isolate_mode |= ISOLATE_CLEAN; >> + if (file) >> + isolate_mode |= ISOLATE_FILE; >> + else >> + isolate_mode |= ISOLATE_ANON; > > Above here, under "if (sc->reclaim_mode& RECLAIM_MODE_LUMPYRECLAIM)", > don't you need > > isolate_mode |= ISOLATE_ACTIVE | ISOLATE_FILE | ISOLATE_ANON; > > now to reproduce the same "all_lru_mode" behaviour as before?
Yes, I missed this. Thanks.
> > Hugh
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