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Message-Id: <20091102093517.32021780.minchan.kim@barrios-desktop>
Date: Mon, 2 Nov 2009 09:35:17 +0900
From: Minchan Kim <minchan.kim@...il.com>
To: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc: "Rafael J. Wysocki" <rjw@...k.pl>, Rik van Riel <riel@...hat.com>,
LKML <linux-kernel@...r.kernel.org>,
linux-mm <linux-mm@...ck.org>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCHv2 1/5] vmscan: separate sc.swap_cluster_max and
sc.nr_max_reclaim
Hi, Kosaki.
On Mon, 2 Nov 2009 00:08:44 +0900 (JST)
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com> wrote:
> Currently, sc.scap_cluster_max has double meanings.
>
> 1) reclaim batch size as isolate_lru_pages()'s argument
> 2) reclaim baling out thresolds
>
> The two meanings pretty unrelated. Thus, Let's separate it.
> this patch doesn't change any behavior.
>
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
> Cc: Rafael J. Wysocki <rjw@...k.pl>
> Reviewed-by: Rik van Riel <riel@...hat.com>
> ---
> mm/vmscan.c | 21 +++++++++++++++------
> 1 files changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index f805958..6a3eb9f 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -55,6 +55,9 @@ struct scan_control {
> /* Number of pages freed so far during a call to shrink_zones() */
> unsigned long nr_reclaimed;
>
> + /* How many pages shrink_list() should reclaim */
> + unsigned long nr_to_reclaim;
If you try to divide meaning of swap_cluster_max,
How about changing 'swap_cluster_max', too?
It has a meaning which represents 'batch size'. ;)
I hope we change it in this chance.
> +
> /* This context's GFP mask */
> gfp_t gfp_mask;
>
> @@ -1585,6 +1588,7 @@ static void shrink_zone(int priority, struct zone *zone,
> enum lru_list l;
> unsigned long nr_reclaimed = sc->nr_reclaimed;
> unsigned long swap_cluster_max = sc->swap_cluster_max;
> + unsigned long nr_to_reclaim = sc->nr_to_reclaim;
> struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
> int noswap = 0;
>
> @@ -1634,8 +1638,7 @@ static void shrink_zone(int priority, struct zone *zone,
> * with multiple processes reclaiming pages, the total
> * freeing target can get unreasonably large.
> */
How about adding following comment or more good one.
'kswapd doesn't bail out because it has 'MAX' nr_to_reclaim'.
> - if (nr_reclaimed > swap_cluster_max &&
> - priority < DEF_PRIORITY && !current_is_kswapd())
> + if (nr_reclaimed > nr_to_reclaim && priority < DEF_PRIORITY)
> break;
> }
>
> @@ -1733,6 +1736,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
> struct zoneref *z;
> struct zone *zone;
> enum zone_type high_zoneidx = gfp_zone(sc->gfp_mask);
> + unsigned long writeback_threshold;
>
> delayacct_freepages_start();
>
> @@ -1768,7 +1772,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
> }
> }
> total_scanned += sc->nr_scanned;
> - if (sc->nr_reclaimed >= sc->swap_cluster_max) {
> + if (sc->nr_reclaimed >= sc->nr_to_reclaim) {
> ret = sc->nr_reclaimed;
> goto out;
> }
> @@ -1780,8 +1784,8 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
> * that's undesirable in laptop mode, where we *want* lumpy
> * writeout. So in laptop mode, write out the whole world.
> */
> - if (total_scanned > sc->swap_cluster_max +
> - sc->swap_cluster_max / 2) {
> + writeback_threshold = sc->nr_to_reclaim + sc->nr_to_reclaim / 2;
> + if (total_scanned > writeback_threshold) {
> wakeup_flusher_threads(laptop_mode ? 0 : total_scanned);
> sc->may_writepage = 1;
> }
> @@ -1827,6 +1831,7 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
> .gfp_mask = gfp_mask,
> .may_writepage = !laptop_mode,
> .swap_cluster_max = SWAP_CLUSTER_MAX,
> + .nr_to_reclaim = SWAP_CLUSTER_MAX,
> .may_unmap = 1,
> .may_swap = 1,
> .swappiness = vm_swappiness,
> @@ -1885,6 +1890,7 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
> .may_unmap = 1,
> .may_swap = !noswap,
> .swap_cluster_max = SWAP_CLUSTER_MAX,
> + .nr_to_reclaim = SWAP_CLUSTER_MAX,
> .swappiness = swappiness,
> .order = 0,
> .mem_cgroup = mem_cont,
> @@ -1932,6 +1938,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order)
> .may_unmap = 1,
> .may_swap = 1,
>
.swap_cluster_max = SWAP_CLUSTER_MAX,
Or add comment in here.
'kswapd doesn't want to be bailed out while reclaim.'
> + .nr_to_reclaim = ULONG_MAX,
> .swappiness = vm_swappiness,
> .order = order,
> .mem_cgroup = NULL,
> @@ -2549,7 +2556,9 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
> .may_unmap = !!(zone_reclaim_mode & RECLAIM_SWAP),
> .may_swap = 1,
> .swap_cluster_max = max_t(unsigned long, nr_pages,
> - SWAP_CLUSTER_MAX),
> + SWAP_CLUSTER_MAX),
> + .nr_to_reclaim = max_t(unsigned long, nr_pages,
> + SWAP_CLUSTER_MAX),
> .gfp_mask = gfp_mask,
> .swappiness = vm_swappiness,
> .order = order,
> --
> 1.6.2.5
>
>
>
> --
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--
Kind regards,
Minchan Kim
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