From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F11E4C433DF for ; Wed, 20 May 2020 16:31:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CFEDB20759 for ; Wed, 20 May 2020 16:31:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chrisdown.name header.i=@chrisdown.name header.b="ToruOqWt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727006AbgETQbw (ORCPT ); Wed, 20 May 2020 12:31:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47066 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726944AbgETQbq (ORCPT ); Wed, 20 May 2020 12:31:46 -0400 Received: from mail-ed1-x543.google.com (mail-ed1-x543.google.com [IPv6:2a00:1450:4864:20::543]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF1FAC061A0E for ; Wed, 20 May 2020 09:31:44 -0700 (PDT) Received: by mail-ed1-x543.google.com with SMTP id f13so3135457edr.13 for ; Wed, 20 May 2020 09:31:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chrisdown.name; s=google; h=date:from:to:cc:subject:message-id:mime-version:content-disposition; bh=17jQ1Ah04oBToqJwXezLZCoVZLFH+XvWoWdyyqn9mN4=; b=ToruOqWtIPegGVdd3B6jTVoD/jM+3Af1McEs8wIdfzwADuzejeup3xOJQYdm11S4EZ 65f5gLqFmKnxcngv/RXN+x6KKrFXbF2QNkJJEO/INc/RjX4WvlQPN+Bi7MjzN0mt+0WH 8YSuiL7L4Tj+3phhD1zTvajIoimjSyRefUirY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition; bh=17jQ1Ah04oBToqJwXezLZCoVZLFH+XvWoWdyyqn9mN4=; b=obYwGdQPK23l0r1fCwSX9aJb9i6fZic1MF87/nfMRQlIPh7djf90vEZ1+Q9CKLL9/Q bSQxxbtLBM+c3WmpMNCV6gtjeclVaOW9oWaF8hGEBiLOaf9/EpoJfIdLqwWPxXRi19sc 07HvhzIASuG66DHLUIDg/d4Ootcic63D+gecl0lcFS+lvO6DjeVj6M7dS/3pMy/6VcCI +kWWwPUjFxMDn1Fci9kWFJ6rfZb8e6g0knaHEh4/IWlYpVB3dEh3V41lhLQeEGnOCLWb L3LIcgdNm08h40U/7p0mLzX/hJ6q23oZoFtkhJs765YrLWZTBJvkHYUk7XQVasKPc6Ve XaLw== X-Gm-Message-State: AOAM531d44mQVbHWv6q2eRGuNc4zrkyfZIOWpN5joMYQr13FSLL3Sw4U mJK6wYgX/fHEUZzxylb5V+oxVg== X-Google-Smtp-Source: ABdhPJy4Y8SAoa9B33qnxj6nB4l/32rU1XrBuIH6bGgBO5u/ZSRq37k2+8ilcS54Hv60sCMxDciDKg== X-Received: by 2002:a50:9b19:: with SMTP id o25mr4312664edi.141.1589992303655; Wed, 20 May 2020 09:31:43 -0700 (PDT) Received: from localhost ([2620:10d:c093:400::5:758d]) by smtp.gmail.com with ESMTPSA id gx25sm2279074ejb.63.2020.05.20.09.31.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 May 2020 09:31:43 -0700 (PDT) Date: Wed, 20 May 2020 17:31:42 +0100 From: Chris Down To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: [PATCH] mm, memcg: unify reclaim retry limits with page allocator Message-ID: <20200520163142.GA808793@chrisdown.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Reclaim retries have been set to 5 since the beginning of time in 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 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 Cc: Andrew Morton Cc: Johannes Weiner Cc: Michal Hocko --- mm/memcontrol.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b040951ccd6b..d3b23c57bed4 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; @@ -2386,7 +2383,7 @@ 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; if (likely(!nr_pages)) @@ -2438,7 +2435,7 @@ 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; @@ -2557,7 +2554,7 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, 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; @@ -3168,7 +3165,7 @@ 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(); @@ -6001,7 +5998,7 @@ 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; @@ -6049,7 +6046,7 @@ 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; -- 2.26.2