mm: memcontrol: use root_mem_cgroup res_counter
Due to an old optimization to keep expensive res_counter changes at a minimum, the root_mem_cgroup res_counter is never charged; there is no limit at that level anyway, and any statistics can be generated on demand by summing up the counters of all other cgroups. However, with per-cpu charge caches, res_counter operations do not even show up in profiles anymore, so this optimization is no longer necessary. Remove it to simplify the code. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Johannes Weiner
Linus Torvalds
parent
692e7c45d9
commit
05b8430123
1 changed files with 44 additions and 108 deletions
152
mm/memcontrol.c
152
mm/memcontrol.c
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@ -2570,9 +2570,8 @@ static int mem_cgroup_try_charge(struct mem_cgroup *memcg,
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unsigned long nr_reclaimed;
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unsigned long flags = 0;
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unsigned long long size;
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int ret = 0;
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if (mem_cgroup_is_root(memcg))
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goto done;
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retry:
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if (consume_stock(memcg, nr_pages))
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goto done;
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@ -2650,13 +2649,15 @@ static int mem_cgroup_try_charge(struct mem_cgroup *memcg,
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if (!(gfp_mask & __GFP_NOFAIL))
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return -ENOMEM;
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bypass:
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return -EINTR;
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memcg = root_mem_cgroup;
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ret = -EINTR;
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goto retry;
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done_restock:
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if (batch > nr_pages)
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refill_stock(memcg, batch - nr_pages);
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done:
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return 0;
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return ret;
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}
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/**
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@ -2695,13 +2696,11 @@ static struct mem_cgroup *mem_cgroup_try_charge_mm(struct mm_struct *mm,
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static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg,
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unsigned int nr_pages)
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{
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if (!mem_cgroup_is_root(memcg)) {
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unsigned long bytes = nr_pages * PAGE_SIZE;
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unsigned long bytes = nr_pages * PAGE_SIZE;
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res_counter_uncharge(&memcg->res, bytes);
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if (do_swap_account)
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res_counter_uncharge(&memcg->memsw, bytes);
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}
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res_counter_uncharge(&memcg->res, bytes);
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if (do_swap_account)
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res_counter_uncharge(&memcg->memsw, bytes);
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}
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/*
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@ -2713,9 +2712,6 @@ static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg,
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{
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unsigned long bytes = nr_pages * PAGE_SIZE;
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if (mem_cgroup_is_root(memcg))
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return;
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res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes);
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if (do_swap_account)
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res_counter_uncharge_until(&memcg->memsw,
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@ -3943,7 +3939,7 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype,
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* replacement page, so leave it alone when phasing out the
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* page that is unused after the migration.
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*/
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if (!end_migration && !mem_cgroup_is_root(memcg))
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if (!end_migration)
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mem_cgroup_do_uncharge(memcg, nr_pages, ctype);
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return memcg;
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@ -4076,8 +4072,7 @@ void mem_cgroup_uncharge_swap(swp_entry_t ent)
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* We uncharge this because swap is freed. This memcg can
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* be obsolete one. We avoid calling css_tryget_online().
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*/
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if (!mem_cgroup_is_root(memcg))
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res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
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res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
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mem_cgroup_swap_statistics(memcg, false);
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css_put(&memcg->css);
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}
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@ -4767,78 +4762,24 @@ static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
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return retval;
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}
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static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *memcg,
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enum mem_cgroup_stat_index idx)
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{
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struct mem_cgroup *iter;
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long val = 0;
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/* Per-cpu values can be negative, use a signed accumulator */
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for_each_mem_cgroup_tree(iter, memcg)
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val += mem_cgroup_read_stat(iter, idx);
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if (val < 0) /* race ? */
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val = 0;
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return val;
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}
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static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
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{
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u64 val;
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if (!mem_cgroup_is_root(memcg)) {
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if (!swap)
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return res_counter_read_u64(&memcg->res, RES_USAGE);
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else
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return res_counter_read_u64(&memcg->memsw, RES_USAGE);
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}
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/*
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* Transparent hugepages are still accounted for in MEM_CGROUP_STAT_RSS
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* as well as in MEM_CGROUP_STAT_RSS_HUGE.
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*/
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val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE);
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val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS);
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if (swap)
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val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAP);
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return val << PAGE_SHIFT;
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}
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static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
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struct cftype *cft)
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struct cftype *cft)
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{
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struct mem_cgroup *memcg = mem_cgroup_from_css(css);
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u64 val;
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int name;
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enum res_type type;
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type = MEMFILE_TYPE(cft->private);
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name = MEMFILE_ATTR(cft->private);
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enum res_type type = MEMFILE_TYPE(cft->private);
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int name = MEMFILE_ATTR(cft->private);
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switch (type) {
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case _MEM:
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if (name == RES_USAGE)
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val = mem_cgroup_usage(memcg, false);
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else
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val = res_counter_read_u64(&memcg->res, name);
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break;
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return res_counter_read_u64(&memcg->res, name);
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case _MEMSWAP:
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if (name == RES_USAGE)
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val = mem_cgroup_usage(memcg, true);
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else
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val = res_counter_read_u64(&memcg->memsw, name);
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break;
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return res_counter_read_u64(&memcg->memsw, name);
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case _KMEM:
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val = res_counter_read_u64(&memcg->kmem, name);
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return res_counter_read_u64(&memcg->kmem, name);
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break;
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default:
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BUG();
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}
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return val;
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}
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#ifdef CONFIG_MEMCG_KMEM
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@ -5300,7 +5241,10 @@ static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
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if (!t)
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goto unlock;
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usage = mem_cgroup_usage(memcg, swap);
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if (!swap)
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usage = res_counter_read_u64(&memcg->res, RES_USAGE);
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else
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usage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
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/*
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* current_threshold points to threshold just below or equal to usage.
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@ -5396,15 +5340,15 @@ static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
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mutex_lock(&memcg->thresholds_lock);
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if (type == _MEM)
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if (type == _MEM) {
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thresholds = &memcg->thresholds;
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else if (type == _MEMSWAP)
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usage = res_counter_read_u64(&memcg->res, RES_USAGE);
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} else if (type == _MEMSWAP) {
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thresholds = &memcg->memsw_thresholds;
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else
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usage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
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} else
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BUG();
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usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
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/* Check if a threshold crossed before adding a new one */
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if (thresholds->primary)
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__mem_cgroup_threshold(memcg, type == _MEMSWAP);
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@ -5484,18 +5428,19 @@ static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
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int i, j, size;
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mutex_lock(&memcg->thresholds_lock);
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if (type == _MEM)
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if (type == _MEM) {
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thresholds = &memcg->thresholds;
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else if (type == _MEMSWAP)
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usage = res_counter_read_u64(&memcg->res, RES_USAGE);
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} else if (type == _MEMSWAP) {
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thresholds = &memcg->memsw_thresholds;
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else
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usage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
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} else
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BUG();
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if (!thresholds->primary)
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goto unlock;
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usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
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/* Check if a threshold crossed before removing */
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__mem_cgroup_threshold(memcg, type == _MEMSWAP);
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@ -6249,9 +6194,9 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css)
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* core guarantees its existence.
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*/
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} else {
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res_counter_init(&memcg->res, NULL);
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res_counter_init(&memcg->memsw, NULL);
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res_counter_init(&memcg->kmem, NULL);
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res_counter_init(&memcg->res, &root_mem_cgroup->res);
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res_counter_init(&memcg->memsw, &root_mem_cgroup->memsw);
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res_counter_init(&memcg->kmem, &root_mem_cgroup->kmem);
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/*
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* Deeper hierachy with use_hierarchy == false doesn't make
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* much sense so let cgroup subsystem know about this
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@ -6387,13 +6332,7 @@ static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
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/* Handlers for move charge at task migration. */
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static int mem_cgroup_do_precharge(unsigned long count)
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{
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int ret = 0;
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if (mem_cgroup_is_root(mc.to)) {
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mc.precharge += count;
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/* we don't need css_get for root */
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return ret;
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}
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int ret;
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/* Try a single bulk charge without reclaim first */
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ret = mem_cgroup_try_charge(mc.to, GFP_KERNEL & ~__GFP_WAIT, count);
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@ -6700,21 +6639,18 @@ static void __mem_cgroup_clear_mc(void)
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/* we must fixup refcnts and charges */
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if (mc.moved_swap) {
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/* uncharge swap account from the old cgroup */
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if (!mem_cgroup_is_root(mc.from))
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res_counter_uncharge(&mc.from->memsw,
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PAGE_SIZE * mc.moved_swap);
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res_counter_uncharge(&mc.from->memsw,
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PAGE_SIZE * mc.moved_swap);
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for (i = 0; i < mc.moved_swap; i++)
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css_put(&mc.from->css);
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if (!mem_cgroup_is_root(mc.to)) {
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/*
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* we charged both to->res and to->memsw, so we should
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* uncharge to->res.
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*/
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res_counter_uncharge(&mc.to->res,
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PAGE_SIZE * mc.moved_swap);
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}
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/*
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* we charged both to->res and to->memsw, so we should
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* uncharge to->res.
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*/
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res_counter_uncharge(&mc.to->res,
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PAGE_SIZE * mc.moved_swap);
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/* we've already done css_get(mc.to) */
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mc.moved_swap = 0;
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}
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