From: Greg Thelen <gthelen@google.com>
To: Dave Hansen <dave.hansen@linux.intel.com>, linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, Dave Hansen <dave.hansen@linux.intel.com>,
rientjes@google.com, ying.huang@intel.com,
dan.j.williams@intel.com, david@redhat.com, osalvador@suse.de
Subject: Re: [PATCH 07/10] mm/vmscan: add helper for querying ability to age anonymous pages
Date: Fri, 19 Mar 2021 21:05:17 -0700 [thread overview]
Message-ID: <xr93v99mmpvm.fsf@gthelen2.svl.corp.google.com> (raw)
In-Reply-To: <20210305000002.D171810D@viggo.jf.intel.com>
Dave Hansen <dave.hansen@linux.intel.com> wrote:
> From: Dave Hansen <dave.hansen@linux.intel.com>
>
> Anonymous pages are kept on their own LRU(s). These lists could
> theoretically always be scanned and maintained. But, without swap,
> there is currently nothing the kernel can *do* with the results of a
> scanned, sorted LRU for anonymous pages.
>
> A check for '!total_swap_pages' currently serves as a valid check as
> to whether anonymous LRUs should be maintained. However, another
> method will be added shortly: page demotion.
>
> Abstract out the 'total_swap_pages' checks into a helper, give it a
> logically significant name, and check for the possibility of page
> demotion.
Reviewed-by: Greg Thelen <gthelen@google.com>
> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Huang Ying <ying.huang@intel.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: osalvador <osalvador@suse.de>
> ---
>
> b/mm/vmscan.c | 28 +++++++++++++++++++++++++---
> 1 file changed, 25 insertions(+), 3 deletions(-)
>
> diff -puN mm/vmscan.c~mm-vmscan-anon-can-be-aged mm/vmscan.c
> --- a/mm/vmscan.c~mm-vmscan-anon-can-be-aged 2021-03-04 15:35:58.935806422 -0800
> +++ b/mm/vmscan.c 2021-03-04 15:35:58.942806422 -0800
> @@ -2517,6 +2517,26 @@ out:
> }
> }
>
> +/*
> + * Anonymous LRU management is a waste if there is
> + * ultimately no way to reclaim the memory.
> + */
> +bool anon_should_be_aged(struct lruvec *lruvec)
Should this be static?
> +{
> + struct pglist_data *pgdat = lruvec_pgdat(lruvec);
> +
> + /* Aging the anon LRU is valuable if swap is present: */
> + if (total_swap_pages > 0)
> + return true;
> +
> + /* Also valuable if anon pages can be demoted: */
> + if (next_demotion_node(pgdat->node_id) >= 0)
> + return true;
> +
> + /* No way to reclaim anon pages. Should not age anon LRUs: */
> + return false;
> +}
> +
> static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
> {
> unsigned long nr[NR_LRU_LISTS];
> @@ -2626,7 +2646,8 @@ static void shrink_lruvec(struct lruvec
> * Even if we did not try to evict anon pages at all, we want to
> * rebalance the anon lru active/inactive ratio.
> */
> - if (total_swap_pages && inactive_is_low(lruvec, LRU_INACTIVE_ANON))
> + if (anon_should_be_aged(lruvec) &&
> + inactive_is_low(lruvec, LRU_INACTIVE_ANON))
> shrink_active_list(SWAP_CLUSTER_MAX, lruvec,
> sc, LRU_ACTIVE_ANON);
> }
> @@ -3455,10 +3476,11 @@ static void age_active_anon(struct pglis
> struct mem_cgroup *memcg;
> struct lruvec *lruvec;
>
> - if (!total_swap_pages)
> + lruvec = mem_cgroup_lruvec(NULL, pgdat);
> +
> + if (!anon_should_be_aged(lruvec))
> return;
>
> - lruvec = mem_cgroup_lruvec(NULL, pgdat);
> if (!inactive_is_low(lruvec, LRU_INACTIVE_ANON))
> return;
>
> _
next prev parent reply other threads:[~2021-03-20 4:06 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-04 23:59 [PATCH 00/10] [v6] Migrate Pages in lieu of discard Dave Hansen
2021-03-04 23:59 ` [PATCH 01/10] mm/numa: node demotion data structure and lookup Dave Hansen
2021-03-08 23:58 ` Yang Shi
2021-03-04 23:59 ` [PATCH 02/10] mm/numa: automatically generate node migration order Dave Hansen
2021-03-08 23:59 ` Yang Shi
2021-03-04 23:59 ` [PATCH 03/10] mm/migrate: update node demotion order during on hotplug events Dave Hansen
2021-03-09 0:03 ` Yang Shi
2021-03-09 22:07 ` Dave Hansen
2021-03-04 23:59 ` [PATCH 04/10] mm/migrate: make migrate_pages() return nr_succeeded Dave Hansen
2021-03-09 0:05 ` Yang Shi
2021-03-04 23:59 ` [PATCH 05/10] mm/migrate: demote pages during reclaim Dave Hansen
2021-03-09 0:10 ` Yang Shi
2021-03-09 23:05 ` Dave Hansen
2021-03-05 0:00 ` [PATCH 06/10] mm/vmscan: add page demotion counter Dave Hansen
2021-03-09 0:11 ` Yang Shi
2021-03-05 0:00 ` [PATCH 07/10] mm/vmscan: add helper for querying ability to age anonymous pages Dave Hansen
2021-03-09 0:14 ` Yang Shi
2021-03-20 4:05 ` Greg Thelen [this message]
2021-03-05 0:00 ` [PATCH 08/10] mm/vmscan: Consider anonymous pages without swap Dave Hansen
2021-03-09 0:17 ` Yang Shi
2021-03-09 23:08 ` Dave Hansen
2021-03-05 0:00 ` [PATCH 09/10] mm/vmscan: never demote for memcg reclaim Dave Hansen
2021-03-09 0:17 ` Yang Shi
2021-03-05 0:00 ` [PATCH 10/10] mm/migrate: new zone_reclaim_mode to enable reclaim migration Dave Hansen
2021-03-09 0:24 ` Yang Shi
2021-03-09 21:53 ` Dave Hansen
2021-03-09 0:34 ` [PATCH 00/10] [v6] Migrate Pages in lieu of discard Yang Shi
2021-03-09 21:52 ` Dave Hansen
2021-04-01 18:32 [PATCH 00/10] [v7][RESEND] " Dave Hansen
2021-04-01 18:32 ` [PATCH 07/10] mm/vmscan: add helper for querying ability to age anonymous pages Dave Hansen
2021-04-07 18:40 ` Wei Xu
2021-04-09 8:31 ` Oscar Salvador
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