| Message ID | 20210401183233.64A91C97@viggo.jf.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Migrate Pages in lieu of discard | expand |
On Thu, Apr 1, 2021 at 11:35 AM 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. > > Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> > Suggested-by: Yang Shi <yang.shi@linux.alibaba.com> > Reviewed-by: Yang Shi <shy828301@gmail.com> > Cc: Wei Xu <weixugc@google.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 2021-03-31 15:17:20.476000239 -0700 > +++ b/mm/vmscan.c 2021-03-31 15:17:20.487000239 -0700 > @@ -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) I don't see "sc" gets used in can_reclaim_anon_pages(). Remove it? > { > 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); > > @@ -1064,7 +1065,8 @@ 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)); > > @@ -1072,6 +1074,10 @@ 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()) > @@ -1328,7 +1334,7 @@ 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; > @@ -2362,7 +2368,7 @@ 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; > } > @@ -2737,7 +2743,7 @@ 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; > _
diff -puN mm/vmscan.c~never-demote-for-memcg-reclaim mm/vmscan.c --- a/mm/vmscan.c~never-demote-for-memcg-reclaim 2021-03-31 15:17:20.476000239 -0700 +++ b/mm/vmscan.c 2021-03-31 15:17:20.487000239 -0700 @@ -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); @@ -1064,7 +1065,8 @@ 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)); @@ -1072,6 +1074,10 @@ 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()) @@ -1328,7 +1334,7 @@ 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; @@ -2362,7 +2368,7 @@ 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; } @@ -2737,7 +2743,7 @@ 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;