From d977aa939fcaff9000f1ba2cd2d516658fdd1ba8 Mon Sep 17 00:00:00 2001 From: Chris Down Date: Thu, 6 Aug 2020 23:21:58 -0700 Subject: mm, memcg: unify reclaim retry limits with page allocator Reclaim retries have been set to 5 since the beginning of time in commit 66e1707bc346 ("Memory controller: add per cgroup LRU and reclaim"). However, we now have a generally agreed-upon standard for page reclaim: MAX_RECLAIM_RETRIES (currently 16), added many years later in commit 0a0337e0d1d1 ("mm, oom: rework oom detection"). In the absence of a compelling reason to declare an OOM earlier in memcg context than page allocator context, it seems reasonable to supplant MEM_CGROUP_RECLAIM_RETRIES with MAX_RECLAIM_RETRIES, making the page allocator and memcg internals more similar in semantics when reclaim fails to produce results, avoiding premature OOMs or throttling. Signed-off-by: Chris Down Signed-off-by: Andrew Morton Reviewed-by: Shakeel Butt Acked-by: Michal Hocko Cc: Johannes Weiner Cc: Tejun Heo Cc: Roman Gushchin Link: http://lkml.kernel.org/r/da557856c9c7654308eaff4eedc1952a95e8df5f.1594640214.git.chris@chrisdown.name Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) (limited to 'mm/memcontrol.c') diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 9b7a7d0592e5..b4cb1bb61d46 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -73,9 +73,6 @@ EXPORT_SYMBOL(memory_cgrp_subsys); struct mem_cgroup *root_mem_cgroup __read_mostly; -/* The number of times we should retry reclaim failures before giving up. */ -#define MEM_CGROUP_RECLAIM_RETRIES 5 - /* Socket memory accounting disabled? */ static bool cgroup_memory_nosocket; @@ -2538,7 +2535,7 @@ void mem_cgroup_handle_over_high(void) unsigned long pflags; unsigned long nr_reclaimed; unsigned int nr_pages = current->memcg_nr_pages_over_high; - int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; + int nr_retries = MAX_RECLAIM_RETRIES; struct mem_cgroup *memcg; bool in_retry = false; @@ -2615,7 +2612,7 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, unsigned int nr_pages) { unsigned int batch = max(MEMCG_CHARGE_BATCH, nr_pages); - int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; + int nr_retries = MAX_RECLAIM_RETRIES; struct mem_cgroup *mem_over_limit; struct page_counter *counter; unsigned long nr_reclaimed; @@ -2734,7 +2731,7 @@ retry: get_order(nr_pages * PAGE_SIZE)); switch (oom_status) { case OOM_SUCCESS: - nr_retries = MEM_CGROUP_RECLAIM_RETRIES; + nr_retries = MAX_RECLAIM_RETRIES; goto retry; case OOM_FAILED: goto force; @@ -3414,7 +3411,7 @@ static inline bool memcg_has_children(struct mem_cgroup *memcg) */ static int mem_cgroup_force_empty(struct mem_cgroup *memcg) { - int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; + int nr_retries = MAX_RECLAIM_RETRIES; /* we call try-to-free pages for make this cgroup empty */ lru_add_drain_all(); @@ -6235,7 +6232,7 @@ static ssize_t memory_high_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); - unsigned int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; + unsigned int nr_retries = MAX_RECLAIM_RETRIES; bool drained = false; unsigned long high; int err; @@ -6283,7 +6280,7 @@ static ssize_t memory_max_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); - unsigned int nr_reclaims = MEM_CGROUP_RECLAIM_RETRIES; + unsigned int nr_reclaims = MAX_RECLAIM_RETRIES; bool drained = false; unsigned long max; int err; -- cgit v1.2.3