From b51820ebea656be3b48bb16dcdc5ad3f203c4fd7 Mon Sep 17 00:00:00 2001 From: Honggyu Kim Date: Fri, 14 Jun 2024 12:00:07 +0900 Subject: [PATCH] mm/damon/paddr: introduce DAMOS_MIGRATE_COLD action for demotion This patch introduces DAMOS_MIGRATE_COLD action, which is similar to DAMOS_PAGEOUT, but migrate folios to the given 'target_nid' in the sysfs instead of swapping them out. The 'target_nid' sysfs knob informs the migration target node ID. Here is one of the example usage of this 'migrate_cold' action. $ cd /sys/kernel/mm/damon/admin/kdamonds/ $ cat contexts//schemes//action migrate_cold $ echo 2 > contexts//schemes//target_nid $ echo commit > state $ numactl -p 0 ./hot_cold 500M 600M & $ numastat -c -p hot_cold Per-node process memory usage (in MBs) PID Node 0 Node 1 Node 2 Total -------------- ------ ------ ------ ----- 701 (hot_cold) 501 0 601 1101 Since there are some common routines with pageout, many functions have similar logics between pageout and migrate cold. damon_pa_migrate_folio_list() is a minimized version of shrink_folio_list(). Link: https://lkml.kernel.org/r/20240614030010.751-6-honggyu.kim@sk.com Signed-off-by: Honggyu Kim Signed-off-by: Hyeongtak Ji Signed-off-by: SeongJae Park Cc: Gregory Price Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Masami Hiramatsu (Google) Cc: Mathieu Desnoyers Cc: Rakie Kim Cc: Steven Rostedt (Google) Signed-off-by: Andrew Morton --- include/linux/damon.h | 2 + mm/damon/paddr.c | 154 +++++++++++++++++++++++++++++++++++++++ mm/damon/sysfs-schemes.c | 1 + 3 files changed, 157 insertions(+) diff --git a/include/linux/damon.h b/include/linux/damon.h index 21d6b69a015c..56714b6eb0d7 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -105,6 +105,7 @@ struct damon_target { * @DAMOS_NOHUGEPAGE: Call ``madvise()`` for the region with MADV_NOHUGEPAGE. * @DAMOS_LRU_PRIO: Prioritize the region on its LRU lists. * @DAMOS_LRU_DEPRIO: Deprioritize the region on its LRU lists. + * @DAMOS_MIGRATE_COLD: Migrate the regions prioritizing colder regions. * @DAMOS_STAT: Do nothing but count the stat. * @NR_DAMOS_ACTIONS: Total number of DAMOS actions * @@ -122,6 +123,7 @@ enum damos_action { DAMOS_NOHUGEPAGE, DAMOS_LRU_PRIO, DAMOS_LRU_DEPRIO, + DAMOS_MIGRATE_COLD, DAMOS_STAT, /* Do nothing but only record the stat */ NR_DAMOS_ACTIONS, }; diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c index 18797c1b419b..882ae54af829 100644 --- a/mm/damon/paddr.c +++ b/mm/damon/paddr.c @@ -12,6 +12,9 @@ #include #include #include +#include +#include +#include #include "../internal.h" #include "ops-common.h" @@ -325,6 +328,153 @@ static unsigned long damon_pa_deactivate_pages(struct damon_region *r, return damon_pa_mark_accessed_or_deactivate(r, s, false); } +static unsigned int __damon_pa_migrate_folio_list( + struct list_head *migrate_folios, struct pglist_data *pgdat, + int target_nid) +{ + unsigned int nr_succeeded; + nodemask_t allowed_mask = NODE_MASK_NONE; + struct migration_target_control mtc = { + /* + * Allocate from 'node', or fail quickly and quietly. + * When this happens, 'page' will likely just be discarded + * instead of migrated. + */ + .gfp_mask = (GFP_HIGHUSER_MOVABLE & ~__GFP_RECLAIM) | + __GFP_NOWARN | __GFP_NOMEMALLOC | GFP_NOWAIT, + .nid = target_nid, + .nmask = &allowed_mask + }; + + if (pgdat->node_id == target_nid || target_nid == NUMA_NO_NODE) + return 0; + + if (list_empty(migrate_folios)) + return 0; + + /* Migration ignores all cpuset and mempolicy settings */ + migrate_pages(migrate_folios, alloc_migrate_folio, NULL, + (unsigned long)&mtc, MIGRATE_ASYNC, MR_DAMON, + &nr_succeeded); + + return nr_succeeded; +} + +static unsigned int damon_pa_migrate_folio_list(struct list_head *folio_list, + struct pglist_data *pgdat, + int target_nid) +{ + unsigned int nr_migrated = 0; + struct folio *folio; + LIST_HEAD(ret_folios); + LIST_HEAD(migrate_folios); + + while (!list_empty(folio_list)) { + struct folio *folio; + + cond_resched(); + + folio = lru_to_folio(folio_list); + list_del(&folio->lru); + + if (!folio_trylock(folio)) + goto keep; + + /* Relocate its contents to another node. */ + list_add(&folio->lru, &migrate_folios); + folio_unlock(folio); + continue; +keep: + list_add(&folio->lru, &ret_folios); + } + /* 'folio_list' is always empty here */ + + /* Migrate folios selected for migration */ + nr_migrated += __damon_pa_migrate_folio_list( + &migrate_folios, pgdat, target_nid); + /* + * Folios that could not be migrated are still in @migrate_folios. Add + * those back on @folio_list + */ + if (!list_empty(&migrate_folios)) + list_splice_init(&migrate_folios, folio_list); + + try_to_unmap_flush(); + + list_splice(&ret_folios, folio_list); + + while (!list_empty(folio_list)) { + folio = lru_to_folio(folio_list); + list_del(&folio->lru); + folio_putback_lru(folio); + } + + return nr_migrated; +} + +static unsigned long damon_pa_migrate_pages(struct list_head *folio_list, + int target_nid) +{ + int nid; + unsigned long nr_migrated = 0; + LIST_HEAD(node_folio_list); + unsigned int noreclaim_flag; + + if (list_empty(folio_list)) + return nr_migrated; + + noreclaim_flag = memalloc_noreclaim_save(); + + nid = folio_nid(lru_to_folio(folio_list)); + do { + struct folio *folio = lru_to_folio(folio_list); + + if (nid == folio_nid(folio)) { + list_move(&folio->lru, &node_folio_list); + continue; + } + + nr_migrated += damon_pa_migrate_folio_list(&node_folio_list, + NODE_DATA(nid), + target_nid); + nid = folio_nid(lru_to_folio(folio_list)); + } while (!list_empty(folio_list)); + + nr_migrated += damon_pa_migrate_folio_list(&node_folio_list, + NODE_DATA(nid), + target_nid); + + memalloc_noreclaim_restore(noreclaim_flag); + + return nr_migrated; +} + +static unsigned long damon_pa_migrate(struct damon_region *r, struct damos *s) +{ + unsigned long addr, applied; + LIST_HEAD(folio_list); + + for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) { + struct folio *folio = damon_get_folio(PHYS_PFN(addr)); + + if (!folio) + continue; + + if (damos_pa_filter_out(s, folio)) + goto put_folio; + + if (!folio_isolate_lru(folio)) + goto put_folio; + list_add(&folio->lru, &folio_list); +put_folio: + folio_put(folio); + } + applied = damon_pa_migrate_pages(&folio_list, s->target_nid); + cond_resched(); + return applied * PAGE_SIZE; +} + + static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx, struct damon_target *t, struct damon_region *r, struct damos *scheme) @@ -336,6 +486,8 @@ static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx, return damon_pa_mark_accessed(r, scheme); case DAMOS_LRU_DEPRIO: return damon_pa_deactivate_pages(r, scheme); + case DAMOS_MIGRATE_COLD: + return damon_pa_migrate(r, scheme); case DAMOS_STAT: break; default: @@ -356,6 +508,8 @@ static int damon_pa_scheme_score(struct damon_ctx *context, return damon_hot_score(context, r, scheme); case DAMOS_LRU_DEPRIO: return damon_cold_score(context, r, scheme); + case DAMOS_MIGRATE_COLD: + return damon_cold_score(context, r, scheme); default: break; } diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c index 0632d28b67f8..880015d5b5ea 100644 --- a/mm/damon/sysfs-schemes.c +++ b/mm/damon/sysfs-schemes.c @@ -1458,6 +1458,7 @@ static const char * const damon_sysfs_damos_action_strs[] = { "nohugepage", "lru_prio", "lru_deprio", + "migrate_cold", "stat", };