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@xxxxxxxxxx>
Almost-Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
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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