From patchwork Fri Aug 7 06:22:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11704849 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E172B138C for ; Fri, 7 Aug 2020 06:22:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A76222177B for ; Fri, 7 Aug 2020 06:22:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="e9RBW9WT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A76222177B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 383C18D0062; Fri, 7 Aug 2020 02:22:08 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 3596D8D0026; Fri, 7 Aug 2020 02:22:08 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2499F8D0062; Fri, 7 Aug 2020 02:22:08 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0044.hostedemail.com [216.40.44.44]) by kanga.kvack.org (Postfix) with ESMTP id 0F49A8D0026 for ; Fri, 7 Aug 2020 02:22:08 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id CE0642489 for ; Fri, 7 Aug 2020 06:22:07 +0000 (UTC) X-FDA: 77122777494.30.tramp56_0a1043a26fbe Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin30.hostedemail.com (Postfix) with ESMTP id A3237180B3C83 for ; Fri, 7 Aug 2020 06:22:07 +0000 (UTC) X-Spam-Summary: 1,0,0,cd3e6a1d0ac0f79b,d41d8cd98f00b204,akpm@linux-foundation.org,,RULES_HIT:2:41:69:355:379:800:960:967:973:988:989:1260:1263:1345:1359:1381:1431:1437:1535:1605:1730:1747:1777:1792:2198:2199:2393:2525:2553:2559:2563:2682:2685:2731:2859:2890:2897:2898:2902:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3865:3866:3867:3868:3870:3871:3872:3874:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4042:4049:4119:4321:4605:5007:6261:6653:7514:7576:7903:9025:9040:9545:9592:10004:11026:11232:11257:11473:11658:11914:12043:12048:12291:12295:12296:12297:12438:12517:12519:12555:12679:12683:12783:12986:13255:13846:14096:21063:21080:21450:21451:21627:21795:21939:21966:21990:30001:30041:30045:30051:30054:30064:30070:30090,0,RBL:198.145.29.99:@linux-foundation.org:.lbl8.mailshell.net-62.2.0.100 64.100.201.201;04y8txpmq6r3wf9agxwjrrtf37c6focptbh7ruzfjpd739bu8fbmfocssumqoci.ungb8oextncugbezt9dhabjn84emm1erqjtqenb8ixm3dy3nwckiw7gu3b7pmjc.6-lbl8.mailshell.net -223.238 X-HE-Tag: tramp56_0a1043a26fbe X-Filterd-Recvd-Size: 8194 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Fri, 7 Aug 2020 06:22:07 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D6A5222C9F; Fri, 7 Aug 2020 06:22:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596781326; bh=Xl/qgk7bGxv2hcZoa4sFHFFj+X2a7VZedKrg964YjGE=; h=Date:From:To:Subject:In-Reply-To:From; b=e9RBW9WT1ghvckN2BajGS8KneVQzJB4LGYhOdc+NwvXObJ9ULy1ncWb08osRd2nSl PL9HpwhmxwuU+Jb7cdVkJEffb344NxeT5LFoElQl2/0sMfM1mESie1geMQ4mwo+spF eybwk6i5aEawIxC7qRU1b1nei1gH9T/jvmzlyWi4= Date: Thu, 06 Aug 2020 23:22:05 -0700 From: Andrew Morton To: akpm@linux-foundation.org, chris@chrisdown.name, guro@fb.com, hannes@cmpxchg.org, laoar.shao@gmail.com, linux-mm@kvack.org, mhocko@suse.com, mm-commits@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 089/163] mm, memcg: decouple e{low,min} state mutations from protection checks Message-ID: <20200807062205.giFveKsjG%akpm@linux-foundation.org> In-Reply-To: <20200806231643.a2711a608dd0f18bff2caf2b@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: A3237180B3C83 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Chris Down Subject: mm, memcg: decouple e{low,min} state mutations from protection checks mem_cgroup_protected currently is both used to set effective low and min and return a mem_cgroup_protection based on the result. As a user, this can be a little unexpected: it appears to be a simple predicate function, if not for the big warning in the comment above about the order in which it must be executed. This change makes it so that we separate the state mutations from the actual protection checks, which makes it more obvious where we need to be careful mutating internal state, and where we are simply checking and don't need to worry about that. [mhocko@suse.com - don't check protection on root memcgs] Link: http://lkml.kernel.org/r/ff3f915097fcee9f6d7041c084ef92d16aaeb56a.1594638158.git.chris@chrisdown.name Signed-off-by: Chris Down Suggested-by: Johannes Weiner Acked-by: Johannes Weiner Acked-by: Michal Hocko Cc: Roman Gushchin Cc: Yafang Shao Signed-off-by: Andrew Morton --- include/linux/memcontrol.h | 53 +++++++++++++++++++++++++++-------- mm/memcontrol.c | 28 ++++-------------- mm/vmscan.c | 17 ++--------- 3 files changed, 53 insertions(+), 45 deletions(-) --- a/include/linux/memcontrol.h~mm-memcg-decouple-elowmin-state-mutations-from-protection-checks +++ a/include/linux/memcontrol.h @@ -47,12 +47,6 @@ 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; @@ -405,8 +399,36 @@ static inline unsigned long mem_cgroup_p READ_ONCE(memcg->memory.elow)); } -enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root, - struct mem_cgroup *memcg); +void mem_cgroup_calculate_protection(struct mem_cgroup *root, + struct mem_cgroup *memcg); + +static inline bool mem_cgroup_supports_protection(struct mem_cgroup *memcg) +{ + /* + * The root memcg doesn't account charges, and doesn't support + * protection. + */ + return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg); + +} + +static inline bool mem_cgroup_below_low(struct mem_cgroup *memcg) +{ + if (!mem_cgroup_supports_protection(memcg)) + return false; + + return READ_ONCE(memcg->memory.elow) >= + page_counter_read(&memcg->memory); +} + +static inline bool mem_cgroup_below_min(struct mem_cgroup *memcg) +{ + if (!mem_cgroup_supports_protection(memcg)) + return false; + + return READ_ONCE(memcg->memory.emin) >= + page_counter_read(&memcg->memory); +} int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask); @@ -935,10 +957,19 @@ static inline unsigned long mem_cgroup_p return 0; } -static inline enum mem_cgroup_protection mem_cgroup_protected( - struct mem_cgroup *root, struct mem_cgroup *memcg) +static inline void mem_cgroup_calculate_protection(struct mem_cgroup *root, + struct mem_cgroup *memcg) +{ +} + +static inline bool mem_cgroup_below_low(struct mem_cgroup *memcg) +{ + return false; +} + +static inline bool mem_cgroup_below_min(struct mem_cgroup *memcg) { - return MEMCG_PROT_NONE; + return false; } static inline int mem_cgroup_charge(struct page *page, struct mm_struct *mm, --- a/mm/memcontrol.c~mm-memcg-decouple-elowmin-state-mutations-from-protection-checks +++ a/mm/memcontrol.c @@ -6587,21 +6587,15 @@ static unsigned long effective_protectio * * 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 *root, - struct mem_cgroup *memcg) +void mem_cgroup_calculate_protection(struct mem_cgroup *root, + struct mem_cgroup *memcg) { unsigned long usage, parent_usage; struct mem_cgroup *parent; if (mem_cgroup_disabled()) - return MEMCG_PROT_NONE; + return; if (!root) root = root_mem_cgroup; @@ -6614,21 +6608,21 @@ enum mem_cgroup_protection mem_cgroup_pr * that special casing. */ if (memcg == root) - return MEMCG_PROT_NONE; + return; usage = page_counter_read(&memcg->memory); if (!usage) - return MEMCG_PROT_NONE; + return; parent = parent_mem_cgroup(memcg); /* No parent means a non-hierarchical mode on v1 memcg */ if (!parent) - return MEMCG_PROT_NONE; + return; if (parent == root) { memcg->memory.emin = READ_ONCE(memcg->memory.min); memcg->memory.elow = READ_ONCE(memcg->memory.low); - goto out; + return; } parent_usage = page_counter_read(&parent->memory); @@ -6642,14 +6636,6 @@ enum mem_cgroup_protection mem_cgroup_pr READ_ONCE(memcg->memory.low), READ_ONCE(parent->memory.elow), atomic_long_read(&parent->memory.children_low_usage))); - -out: - if (usage <= memcg->memory.emin) - return MEMCG_PROT_MIN; - else if (usage <= memcg->memory.elow) - return MEMCG_PROT_LOW; - else - return MEMCG_PROT_NONE; } /** --- a/mm/vmscan.c~mm-memcg-decouple-elowmin-state-mutations-from-protection-checks +++ a/mm/vmscan.c @@ -2620,14 +2620,15 @@ static void shrink_node_memcgs(pg_data_t unsigned long reclaimed; unsigned long scanned; - switch (mem_cgroup_protected(target_memcg, memcg)) { - case MEMCG_PROT_MIN: + mem_cgroup_calculate_protection(target_memcg, memcg); + + if (mem_cgroup_below_min(memcg)) { /* * Hard protection. * If there is no reclaimable memory, OOM. */ continue; - case MEMCG_PROT_LOW: + } else if (mem_cgroup_below_low(memcg)) { /* * Soft protection. * Respect the protection only as long as @@ -2639,16 +2640,6 @@ static void shrink_node_memcgs(pg_data_t 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;