Messages in this thread | | | Date | Fri, 2 Mar 2012 16:22:25 -0800 (PST) | From | Hugh Dickins <> | Subject | Re: [PATCH 3/7] mm: rework __isolate_lru_page() file/anon filter |
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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.
> --- > 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?
Hugh
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