Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751287AbdCQX0t (ORCPT ); Fri, 17 Mar 2017 19:26:49 -0400 Received: from mail-pf0-f182.google.com ([209.85.192.182]:32829 "EHLO mail-pf0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751100AbdCQX0r (ORCPT ); Fri, 17 Mar 2017 19:26:47 -0400 From: Tim Murray To: Johannes Weiner , Michal Hocko , Vladimir Davydov , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, surenb@google.com, totte@google.com, kernel-team@android.com Cc: Tim Murray Subject: [RFC 1/1] mm, memcg: add prioritized reclaim Date: Fri, 17 Mar 2017 16:16:36 -0700 Message-Id: <20170317231636.142311-2-timmurray@google.com> X-Mailer: git-send-email 2.12.0.367.g23dc2f6d3c-goog In-Reply-To: <20170317231636.142311-1-timmurray@google.com> References: <20170317231636.142311-1-timmurray@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4766 Lines: 174 When a system is under memory pressure, it may be beneficial to prioritize some memory cgroups to keep their pages resident ahead of other cgroups' pages. Add a new interface to memory cgroups, memory.priority, that enables kswapd and direct reclaim to scan more pages in lower-priority cgroups before looking at higher-priority cgroups. Signed-off-by: Tim Murray --- include/linux/memcontrol.h | 20 +++++++++++++++++++- mm/memcontrol.c | 33 +++++++++++++++++++++++++++++++++ mm/vmscan.c | 3 ++- 3 files changed, 54 insertions(+), 2 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 5af377303880..0d0f95839a8d 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -206,7 +206,9 @@ struct mem_cgroup { bool oom_lock; int under_oom; - int swappiness; + int swappiness; + int priority; + /* OOM-Killer disable */ int oom_kill_disable; @@ -487,6 +489,16 @@ static inline bool task_in_memcg_oom(struct task_struct *p) bool mem_cgroup_oom_synchronize(bool wait); +static inline int mem_cgroup_priority(struct mem_cgroup *memcg) +{ + /* root ? */ + if (mem_cgroup_disabled() || !memcg->css.parent) + return 0; + + return memcg->priority; +} + + #ifdef CONFIG_MEMCG_SWAP extern int do_swap_account; #endif @@ -766,6 +778,12 @@ static inline void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx) { } + +static inline int mem_cgroup_priority(struct mem_cgroup *memcg) +{ + return 0; +} + #endif /* CONFIG_MEMCG */ #ifdef CONFIG_CGROUP_WRITEBACK diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 2bd7541d7c11..7343ca106a36 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -81,6 +81,8 @@ struct mem_cgroup *root_mem_cgroup __read_mostly; #define MEM_CGROUP_RECLAIM_RETRIES 5 +#define MEM_CGROUP_PRIORITY_MAX 10 + /* Socket memory accounting disabled? */ static bool cgroup_memory_nosocket; @@ -241,6 +243,7 @@ enum res_type { _OOM_TYPE, _KMEM, _TCP, + _PRIO, }; #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val)) @@ -842,6 +845,10 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, */ memcg = mem_cgroup_from_css(css); + if (reclaim && reclaim->priority && + (DEF_PRIORITY - memcg->priority) < reclaim->priority) + continue; + if (css == &root->css) break; @@ -2773,6 +2780,7 @@ enum { RES_MAX_USAGE, RES_FAILCNT, RES_SOFT_LIMIT, + RES_PRIORITY, }; static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css, @@ -2783,6 +2791,7 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css, switch (MEMFILE_TYPE(cft->private)) { case _MEM: + case _PRIO: counter = &memcg->memory; break; case _MEMSWAP: @@ -2813,6 +2822,8 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css, return counter->failcnt; case RES_SOFT_LIMIT: return (u64)memcg->soft_limit * PAGE_SIZE; + case RES_PRIORITY: + return (u64)memcg->priority; default: BUG(); } @@ -2966,6 +2977,22 @@ static int memcg_update_tcp_limit(struct mem_cgroup *memcg, unsigned long limit) return ret; } +static ssize_t mem_cgroup_update_prio(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 long long prio = -1; + + buf = strstrip(buf); + prio = memparse(buf, NULL); + + if (prio >= 0 && prio <= MEM_CGROUP_PRIORITY_MAX) { + memcg->priority = (int)prio; + return nbytes; + } + return -EINVAL; +} + /* * The user of this function is... * RES_LIMIT. @@ -3940,6 +3967,12 @@ static struct cftype mem_cgroup_legacy_files[] = { .read_u64 = mem_cgroup_read_u64, }, { + .name = "priority", + .private = MEMFILE_PRIVATE(_PRIO, RES_PRIORITY), + .write = mem_cgroup_update_prio, + .read_u64 = mem_cgroup_read_u64, + }, + { .name = "stat", .seq_show = memcg_stat_show, }, diff --git a/mm/vmscan.c b/mm/vmscan.c index bc8031ef994d..c47b21326ab0 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2116,6 +2116,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg, unsigned long *lru_pages) { int swappiness = mem_cgroup_swappiness(memcg); + int priority = mem_cgroup_priority(memcg); struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat; u64 fraction[2]; u64 denominator = 0; /* gcc */ @@ -2287,7 +2288,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg, unsigned long scan; size = lruvec_lru_size(lruvec, lru, sc->reclaim_idx); - scan = size >> sc->priority; + scan = size >> (sc->priority + priority); if (!scan && pass && force_scan) scan = min(size, SWAP_CLUSTER_MAX); -- 2.12.0.367.g23dc2f6d3c-goog