From: Yang Shi <shy828301@gmail.com>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux MM <linux-mm@kvack.org>,
Yang Shi <yang.shi@linux.alibaba.com>,
David Rientjes <rientjes@google.com>,
Huang Ying <ying.huang@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
David Hildenbrand <david@redhat.com>,
Oscar Salvador <osalvador@suse.de>
Subject: Re: [PATCH 09/10] mm/vmscan: never demote for memcg reclaim
Date: Mon, 8 Mar 2021 16:17:58 -0800 [thread overview]
Message-ID: <CAHbLzkrugnnsSN-z9GBZ+=KqPt3F=B=TPUGXpLdr1S1j5L8_VQ@mail.gmail.com> (raw)
In-Reply-To: <20210305000006.3799F4BE@viggo.jf.intel.com>
On Thu, Mar 4, 2021 at 4:02 PM Dave Hansen <dave.hansen@linux.intel.com> wrote:
>
>
> From: Dave Hansen <dave.hansen@linux.intel.com>
>
> Global reclaim aims to reduce the amount of memory used on
> a given node or set of nodes. Migrating pages to another
> node serves this purpose.
>
> memcg reclaim is different. Its goal is to reduce the
> total memory consumption of the entire memcg, across all
> nodes. Migration does not assist memcg reclaim because
> it just moves page contents between nodes rather than
> actually reducing memory consumption.
Reviewed-by: Yang Shi <shy828301@gmail.com>
>
> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
> Suggested-by: Yang Shi <yang.shi@linux.alibaba.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 | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff -puN mm/vmscan.c~never-demote-for-memcg-reclaim mm/vmscan.c
> --- a/mm/vmscan.c~never-demote-for-memcg-reclaim 2021-03-04 15:36:01.067806417 -0800
> +++ b/mm/vmscan.c 2021-03-04 15:36:01.072806417 -0800
> @@ -288,7 +288,8 @@ static bool writeback_throttling_sane(st
> #endif
>
> static inline bool can_reclaim_anon_pages(struct mem_cgroup *memcg,
> - int node_id)
> + int node_id,
> + struct scan_control *sc)
> {
> if (memcg == NULL) {
> /*
> @@ -326,7 +327,7 @@ unsigned long zone_reclaimable_pages(str
>
> nr = zone_page_state_snapshot(zone, NR_ZONE_INACTIVE_FILE) +
> zone_page_state_snapshot(zone, NR_ZONE_ACTIVE_FILE);
> - if (can_reclaim_anon_pages(NULL, zone_to_nid(zone)))
> + if (can_reclaim_anon_pages(NULL, zone_to_nid(zone), NULL))
> nr += zone_page_state_snapshot(zone, NR_ZONE_INACTIVE_ANON) +
> zone_page_state_snapshot(zone, NR_ZONE_ACTIVE_ANON);
>
> @@ -1063,7 +1064,8 @@ static enum page_references page_check_r
> return PAGEREF_RECLAIM;
> }
>
> -static bool migrate_demote_page_ok(struct page *page)
> +static bool migrate_demote_page_ok(struct page *page,
> + struct scan_control *sc)
> {
> int next_nid = next_demotion_node(page_to_nid(page));
>
> @@ -1071,6 +1073,10 @@ static bool migrate_demote_page_ok(struc
> VM_BUG_ON_PAGE(PageHuge(page), page);
> VM_BUG_ON_PAGE(PageLRU(page), page);
>
> + /* It is pointless to do demotion in memcg reclaim */
> + if (cgroup_reclaim(sc))
> + return false;
> +
> if (next_nid == NUMA_NO_NODE)
> return false;
> if (PageTransHuge(page) && !thp_migration_supported())
> @@ -1326,7 +1332,7 @@ retry:
> * Before reclaiming the page, try to relocate
> * its contents to another node.
> */
> - if (do_demote_pass && migrate_demote_page_ok(page)) {
> + if (do_demote_pass && migrate_demote_page_ok(page, sc)) {
> list_add(&page->lru, &demote_pages);
> unlock_page(page);
> continue;
> @@ -2371,7 +2377,7 @@ static void get_scan_count(struct lruvec
> enum lru_list lru;
>
> /* If we have no swap space, do not bother scanning anon pages. */
> - if (!sc->may_swap || !can_reclaim_anon_pages(memcg, pgdat->node_id)) {
> + if (!sc->may_swap || !can_reclaim_anon_pages(memcg, pgdat->node_id, sc)) {
> scan_balance = SCAN_FILE;
> goto out;
> }
> @@ -2746,7 +2752,7 @@ static inline bool should_continue_recla
> */
> pages_for_compaction = compact_gap(sc->order);
> inactive_lru_pages = node_page_state(pgdat, NR_INACTIVE_FILE);
> - if (can_reclaim_anon_pages(NULL, pgdat->node_id))
> + if (can_reclaim_anon_pages(NULL, pgdat->node_id, sc))
> inactive_lru_pages += node_page_state(pgdat, NR_INACTIVE_ANON);
>
> return inactive_lru_pages > pages_for_compaction;
> _
>
next prev parent reply other threads:[~2021-03-09 0:19 UTC|newest]
Thread overview: 30+ 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
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 [this message]
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 09/10] mm/vmscan: never demote for memcg reclaim Dave Hansen
2021-04-02 0:18 ` Wei Xu
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