[3/3] mm: improvements on memcg protection functions

Message ID	20200425152418.28388-4-laoar.shao@gmail.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <SRS0=CnwN=6J=kvack.org=owner-linux-mm@kernel.org> DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B684720748 From: Yafang Shao <laoar.shao@gmail.com> To: akpm@linux-foundation.org, hannes@cmpxchg.org, mhocko@kernel.org, guro@fb.com, chris@chrisdown.name Cc: linux-mm@kvack.org, Yafang Shao <laoar.shao@gmail.com> Subject: [PATCH 3/3] mm: improvements on memcg protection functions Date: Sat, 25 Apr 2020 11:24:18 -0400 Message-Id: <20200425152418.28388-4-laoar.shao@gmail.com> In-Reply-To: <20200425152418.28388-1-laoar.shao@gmail.com> References: <20200425152418.28388-1-laoar.shao@gmail.com> Sender: owner-linux-mm@kvack.org Precedence: bulk
Series	mm: improve proportional memcg protection \| expand [0/3] mm: improve proportional memcg protection [1/3] mm: move struct scan_control into internal.h [2/3] mm: add reclaim context as a new parameter in mem_cgroup_protected() [3/3] mm: improvements on memcg protection functions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index b327857a1e7e..9d5ceeba3b31 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -50,12 +50,6 @@ enum memcg_memory_event { MEMCG_NR_MEMORY_EVENTS, }; -enum mem_cgroup_protection { - MEMCG_PROT_NONE, - MEMCG_PROT_LOW, - MEMCG_PROT_MIN, -}; - struct mem_cgroup_reclaim_cookie { pg_data_t *pgdat; unsigned int generation; @@ -344,19 +338,6 @@ static inline bool mem_cgroup_disabled(void) return !cgroup_subsys_enabled(memory_cgrp_subsys); } -static inline unsigned long mem_cgroup_protection(struct mem_cgroup *memcg, - bool in_low_reclaim) -{ - if (mem_cgroup_disabled()) - return 0; - - if (in_low_reclaim) - return READ_ONCE(memcg->memory.emin); - - return max(READ_ONCE(memcg->memory.emin), - READ_ONCE(memcg->memory.elow)); -} - int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask, struct mem_cgroup **memcgp, bool compound); @@ -832,12 +813,6 @@ static inline void memcg_memory_event_mm(struct mm_struct *mm, { } -static inline unsigned long mem_cgroup_protection(struct mem_cgroup *memcg, - bool in_low_reclaim) -{ - return 0; -} - static inline int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask, struct mem_cgroup **memcgp, diff --git a/mm/internal.h b/mm/internal.h index a0b3bdd933b9..10c762a79c0c 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -271,6 +271,9 @@ struct scan_control { */ struct mem_cgroup *target_mem_cgroup; + /* Memcg protection in this reclaim context */ + unsigned long protection; + /* Can active pages be deactivated as part of reclaim? */ #define DEACTIVATE_ANON 1 #define DEACTIVATE_FILE 2 @@ -338,6 +341,20 @@ struct scan_control { struct reclaim_state reclaim_state; }; +#ifdef CONFIG_MEMCG +bool mem_cgroup_protected(struct mem_cgroup *target, + struct mem_cgroup *memcg, + struct scan_control *sc); + +#else +static inline bool mem_cgroup_protected(struct mem_cgroup *target, + struct mem_cgroup *memcg, + struct scan_control *sc) +{ + return false; +} +#endif + /* * This function returns the order of a free page in the buddy system. In * general, page_zone(page)->lock must be held by the caller to prevent the diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 51dab7f2e714..f2f191898f2b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6372,35 +6372,30 @@ static unsigned long effective_protection(unsigned long usage, * WARNING: This function is not stateless! It can only be used as part * of a top-down tree iteration, not for isolated queries. * - * Returns one of the following: - * MEMCG_PROT_NONE: cgroup memory is not protected - * MEMCG_PROT_LOW: cgroup memory is protected as long there is - * an unprotected supply of reclaimable memory from other cgroups. - * MEMCG_PROT_MIN: cgroup memory is protected */ -enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *target, - struct mem_cgroup *memcg, - struct scan_control *sc) +bool mem_cgroup_protected(struct mem_cgroup *target, + struct mem_cgroup *memcg, + struct scan_control *sc) { unsigned long usage, parent_usage; struct mem_cgroup *parent; if (mem_cgroup_disabled()) - return MEMCG_PROT_NONE; + return false; if (!target) target = root_mem_cgroup; if (memcg == target) - return MEMCG_PROT_NONE; + return false; usage = page_counter_read(&memcg->memory); if (!usage) - return MEMCG_PROT_NONE; + return false; parent = parent_mem_cgroup(memcg); /* No parent means a non-hierarchical mode on v1 memcg */ if (!parent) - return MEMCG_PROT_NONE; + return false; if (parent == target) { memcg->memory.emin = READ_ONCE(memcg->memory.min); @@ -6420,12 +6415,43 @@ enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *target, atomic_long_read(&parent->memory.children_low_usage))); out: + /* + * Hard protection. + * If there is no reclaimable memory, OOM. + */ if (usage <= memcg->memory.emin) - return MEMCG_PROT_MIN; - else if (usage <= memcg->memory.elow) - return MEMCG_PROT_LOW; + return true; + + /* The protection takes effect when false is returned. */ + if (sc->memcg_low_reclaim) + sc->protection = memcg->memory.emin; else - return MEMCG_PROT_NONE; + sc->protection = max(memcg->memory.emin, memcg->memory.elow); + + if (usage <= memcg->memory.elow) { + /* + * Soft protection. + * Respect the protection only as long as there is an + * unprotected supply of reclaimable memory from other + * cgroups. + */ + if (!sc->memcg_low_reclaim) { + sc->memcg_low_skipped = 1; + return true; + } + + memcg_memory_event(memcg, MEMCG_LOW); + + return false; + } + + /* + * All protection thresholds breached. We may still choose to vary + * the scan pressure applied based on by how much the cgroup in + * question has exceeded its protection thresholds + * (see get_scan_count). + */ + return false; } /** diff --git a/mm/vmscan.c b/mm/vmscan.c index 61c944e7f587..a81bf736ac11 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2263,8 +2263,7 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc, unsigned long protection; lruvec_size = lruvec_lru_size(lruvec, lru, sc->reclaim_idx); - protection = mem_cgroup_protection(memcg, - sc->memcg_low_reclaim); + protection = sc->protection; if (protection) { /* @@ -2551,36 +2550,10 @@ static void shrink_node_memcgs(pg_data_t *pgdat, struct scan_control *sc) unsigned long reclaimed; unsigned long scanned; - switch (mem_cgroup_protected(target_memcg, memcg, sc)) { - case MEMCG_PROT_MIN: - /* - * Hard protection. - * If there is no reclaimable memory, OOM. - */ + sc->protection = 0; + + if (mem_cgroup_protected(target_memcg, memcg, sc)) continue; - case MEMCG_PROT_LOW: - /* - * Soft protection. - * Respect the protection only as long as - * there is an unprotected supply - * of reclaimable memory from other cgroups. - */ - if (!sc->memcg_low_reclaim) { - sc->memcg_low_skipped = 1; - continue; - } - memcg_memory_event(memcg, MEMCG_LOW); - break; - case MEMCG_PROT_NONE: - /* - * All protection thresholds breached. We may - * still choose to vary the scan pressure - * applied based on by how much the cgroup in - * question has exceeded its protection - * thresholds (see get_scan_count). - */ - break; - } reclaimed = sc->nr_reclaimed; scanned = sc->nr_scanned;

[3/3] mm: improvements on memcg protection functions

Commit Message

Comments

Patch