From patchwork Mon Mar 13 11:28:15 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qi Zheng X-Patchwork-Id: 13172284 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id D6ADCC61DA4 for ; Mon, 13 Mar 2023 11:30:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 701246B0078; Mon, 13 Mar 2023 07:30:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 695476B007B; Mon, 13 Mar 2023 07:30:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4DE0C6B007D; Mon, 13 Mar 2023 07:30:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 405816B0078 for ; Mon, 13 Mar 2023 07:30:06 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 194BE1C6243 for ; Mon, 13 Mar 2023 11:30:06 +0000 (UTC) X-FDA: 80563656012.21.8EB96A0 Received: from mail-pg1-f175.google.com (mail-pg1-f175.google.com [209.85.215.175]) by imf12.hostedemail.com (Postfix) with ESMTP id 4363940020 for ; Mon, 13 Mar 2023 11:30:03 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=bytedance.com header.s=google header.b=gxoAK0RJ; spf=pass (imf12.hostedemail.com: domain of zhengqi.arch@bytedance.com designates 209.85.215.175 as permitted sender) smtp.mailfrom=zhengqi.arch@bytedance.com; dmarc=pass (policy=none) header.from=bytedance.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1678707004; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=joJBORpGAhUrTa0QaRmWtbHEppwsJHnBnzSS2GFBqpE=; b=JCj7Qg63cVZlrRYRaZ1eRUYUj35DZEhVUXRmauLwTTSuy1KB+2PrvUkOukovnFPZVDNXMw o24lwpHPz5iQ2hALwZBGUTYqbITtcp3UkdXEUcf0037ZH6ZsCuJF9+vWvLgA3P7vQhmG7v pi4Oy9d2xIU9AjDxY47ma87SDXmYDBg= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=bytedance.com header.s=google header.b=gxoAK0RJ; spf=pass (imf12.hostedemail.com: domain of zhengqi.arch@bytedance.com designates 209.85.215.175 as permitted sender) smtp.mailfrom=zhengqi.arch@bytedance.com; dmarc=pass (policy=none) header.from=bytedance.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1678707004; a=rsa-sha256; cv=none; b=eG5aePxdnckjopw818xjo+XW3QsJJ4zm0bF8gbJm++CKs0XMbBEHGehKdnaR059ksOYc6g z6HF8t1ZwmaYiCRP/C1Tv8PU6cIFke3iMO0Iks4B4Lm4A7R1+owM3XzfJy7EE2HGFS5862 pcud38/xN27iyKWoBDerlDKaJIGRUYc= Received: by mail-pg1-f175.google.com with SMTP id h31so6682433pgl.6 for ; Mon, 13 Mar 2023 04:30:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1678707003; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=joJBORpGAhUrTa0QaRmWtbHEppwsJHnBnzSS2GFBqpE=; b=gxoAK0RJLeAUG9DMQX3AJ19hEgYUC73gn5qDU+xe20VchIqQl4+4Bs8TMoR+xUoHKj ND9SsfWlrkOJpCkSW9SdC0rMfbp2pkoC+L+Zsl8WbNt1tGBTAG2LXwZTOyMQ1iLcCwQd GxK8VSLfc4QaraebduBNkUss03AkdhgD0s4yXld1S43G6GFxDxgVa30i3fDKmLe2+vsn L0khGXfZPxYQ4maITGQLyGizgnKgpvbt2obFC6FA/0459J8cOE4CnMELpfc1XfocweG3 UCt1lbaasgjVAeNzd0lchgP8FL0nLDv/KuKuOjPDpVlt6/LjMfKic6NSPuZGnknpbpu6 jdFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678707003; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=joJBORpGAhUrTa0QaRmWtbHEppwsJHnBnzSS2GFBqpE=; b=2D/ZFpjCjbrcf1ZThaW/vqhGBNUY9dOeCSStYLts+a219a/Tdca72gr6eY+BHkJ2xl PV0koLDXRSLtMlGJJJeYDG92XnRIpryFNVZqLXso9qq/gNXMX7RD6Vl8eu7Beit+3QRU nROhXWRh8M21r5ILc3T+SwGnyeAtSwOGSKPqYP3b1uVRWLBHVCsfltqRJIVf4m8cuTv5 0Z7+NrexbJnt85n8Z/OADLbKvvWO4sWY6hRCkHpKDdy4nRwgp1aSNvxRYp4qjLz29fhI la6nKZSkbrjp2oWaqfcJHQeG8M0zhME0vLje7PG2GZiy7bogk8By3BWI25BC3mCotSdt OALw== X-Gm-Message-State: AO0yUKV+3qzCfegRRjOKPqp1NwBxQJRRSlgdi9MzHa6yzX8rNnTfoYgE QhaZlKEeXYJkQZb80wZoxz74GA== X-Google-Smtp-Source: AK7set8YFjpOWP7oOMMANTE81hjqmcZGdje1Alhj8F/KolKsPGx7n3vdYEg4ks+PCVoaRcuIXePCBQ== X-Received: by 2002:a05:6a00:2148:b0:606:d3d1:4cc4 with SMTP id o8-20020a056a00214800b00606d3d14cc4mr10843183pfk.3.1678707003039; Mon, 13 Mar 2023 04:30:03 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([139.177.225.229]) by smtp.gmail.com with ESMTPSA id n2-20020a654882000000b0050300a7c8c2sm4390827pgs.89.2023.03.13.04.29.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Mar 2023 04:30:02 -0700 (PDT) From: Qi Zheng To: akpm@linux-foundation.org, tkhai@ya.ru, vbabka@suse.cz, christian.koenig@amd.com, hannes@cmpxchg.org, shakeelb@google.com, mhocko@kernel.org, roman.gushchin@linux.dev, muchun.song@linux.dev, david@redhat.com, shy828301@gmail.com Cc: sultan@kerneltoast.com, dave@stgolabs.net, penguin-kernel@I-love.SAKURA.ne.jp, paulmck@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qi Zheng Subject: [PATCH v5 4/8] mm: vmscan: add shrinker_srcu_generation Date: Mon, 13 Mar 2023 19:28:15 +0800 Message-Id: <20230313112819.38938-5-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20230313112819.38938-1-zhengqi.arch@bytedance.com> References: <20230313112819.38938-1-zhengqi.arch@bytedance.com> MIME-Version: 1.0 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 4363940020 X-Stat-Signature: 9igc1q44w5yw984rrmwnig4hdtd48qme X-Rspam-User: X-HE-Tag: 1678707003-343851 X-HE-Meta: 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 khUmMt9F 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 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: Kirill Tkhai After we make slab shrink lockless with SRCU, the longest sleep unregister_shrinker() will be a sleep waiting for all do_shrink_slab() calls. To avoid long unbreakable action in the unregister_shrinker(), add shrinker_srcu_generation to restore a check similar to the rwsem_is_contendent() check that we had before. And for memcg slab shrink, we unlock SRCU and continue iterations from the next shrinker id. Signed-off-by: Kirill Tkhai Signed-off-by: Qi Zheng Acked-by: Vlastimil Babka --- mm/vmscan.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index ce7834030f75..5c2a22454320 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -204,6 +204,7 @@ static void set_task_reclaim_state(struct task_struct *task, LIST_HEAD(shrinker_list); DECLARE_RWSEM(shrinker_rwsem); DEFINE_SRCU(shrinker_srcu); +static atomic_t shrinker_srcu_generation = ATOMIC_INIT(0); #ifdef CONFIG_MEMCG static int shrinker_nr_max; @@ -776,6 +777,7 @@ void unregister_shrinker(struct shrinker *shrinker) debugfs_entry = shrinker_debugfs_remove(shrinker); up_write(&shrinker_rwsem); + atomic_inc(&shrinker_srcu_generation); synchronize_srcu(&shrinker_srcu); debugfs_remove_recursive(debugfs_entry); @@ -797,6 +799,7 @@ void synchronize_shrinkers(void) { down_write(&shrinker_rwsem); up_write(&shrinker_rwsem); + atomic_inc(&shrinker_srcu_generation); synchronize_srcu(&shrinker_srcu); } EXPORT_SYMBOL(synchronize_shrinkers); @@ -906,18 +909,20 @@ static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid, { struct shrinker_info *info; unsigned long ret, freed = 0; - int srcu_idx; - int i; + int srcu_idx, generation; + int i = 0; if (!mem_cgroup_online(memcg)) return 0; +again: srcu_idx = srcu_read_lock(&shrinker_srcu); info = shrinker_info_srcu(memcg, nid); if (unlikely(!info)) goto unlock; - for_each_set_bit(i, info->map, info->map_nr_max) { + generation = atomic_read(&shrinker_srcu_generation); + for_each_set_bit_from(i, info->map, info->map_nr_max) { struct shrink_control sc = { .gfp_mask = gfp_mask, .nid = nid, @@ -963,6 +968,11 @@ static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid, set_shrinker_bit(memcg, nid, i); } freed += ret; + if (atomic_read(&shrinker_srcu_generation) != generation) { + srcu_read_unlock(&shrinker_srcu, srcu_idx); + i++; + goto again; + } } unlock: srcu_read_unlock(&shrinker_srcu, srcu_idx); @@ -1002,7 +1012,7 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid, { unsigned long ret, freed = 0; struct shrinker *shrinker; - int srcu_idx; + int srcu_idx, generation; /* * The root memcg might be allocated even though memcg is disabled @@ -1016,6 +1026,7 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid, srcu_idx = srcu_read_lock(&shrinker_srcu); + generation = atomic_read(&shrinker_srcu_generation); list_for_each_entry_srcu(shrinker, &shrinker_list, list, srcu_read_lock_held(&shrinker_srcu)) { struct shrink_control sc = { @@ -1028,6 +1039,11 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid, if (ret == SHRINK_EMPTY) ret = 0; freed += ret; + + if (atomic_read(&shrinker_srcu_generation) != generation) { + freed = freed ? : 1; + break; + } } srcu_read_unlock(&shrinker_srcu, srcu_idx);