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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1C80FC3ABC3 for ; Tue, 13 May 2025 03:14:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0E09A6B009B; Mon, 12 May 2025 23:14:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 090776B009C; Mon, 12 May 2025 23:14:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E9CFF6B009D; Mon, 12 May 2025 23:14:50 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id C38D06B009B for ; Mon, 12 May 2025 23:14:50 -0400 (EDT) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 0E9F214132B for ; Tue, 13 May 2025 03:14:52 +0000 (UTC) X-FDA: 83436417624.02.73759C5 Received: from out-183.mta0.migadu.com (out-183.mta0.migadu.com [91.218.175.183]) by imf08.hostedemail.com (Postfix) with ESMTP id 82DB3160004 for ; Tue, 13 May 2025 03:14:50 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=VHLI3S18; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf08.hostedemail.com: domain of shakeel.butt@linux.dev designates 91.218.175.183 as permitted sender) smtp.mailfrom=shakeel.butt@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1747106090; a=rsa-sha256; cv=none; b=bylitaIShisUHSKgCjI1ZHP7pzlef90ur0XBnVMDruhcmksJYG1HYaAdzyiPd7ovlD317V wvHLLeCgZAd9TNjRXmz+DV/BV24xwjtWN6BOA9ceOmGbKQxibljH0P3iHqLuNbDEPMFpcK nLHtaPz9o47DgdATfMZFYmeUr5gSNqk= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=VHLI3S18; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf08.hostedemail.com: domain of shakeel.butt@linux.dev designates 91.218.175.183 as permitted sender) smtp.mailfrom=shakeel.butt@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1747106090; 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=FByBL+Uk6nVPajbs5jWaOtV9bA6rKUCuGTge/ypRKI4=; b=4Os0Fu4nGo4yhpKHUBoO9QVj0dibTTkRvXg4spE19vyUn9Rnr+7Ji8e29GDRsrCWlCHtI1 Qnj46USYAI/Y1viCfNTupoyUTXOwZCwTe9oWpxm6rLP0nXaK/3DH0v/lBAKTWJVsuCyBdP V7S01IB5gIcxAcwhKHDRuyPD0+/F3o0= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1747106089; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FByBL+Uk6nVPajbs5jWaOtV9bA6rKUCuGTge/ypRKI4=; b=VHLI3S18C0ilRJtHPuy5DdQfm7qGScWd+9hI+WlIJvZueihhycJEFqGZU2rpRElPW0R7dG eRrrEvnQdBtAUsWD0dya+31904+ICeO+NjH2WCcHY18grx/0I+CEACOvkXQojrVYoAv2gN mjw9+y9HBGPc9spYYkZCsrqOavp9eyE= From: Shakeel Butt To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Vlastimil Babka , Alexei Starovoitov , Sebastian Andrzej Siewior , Harry Yoo , Yosry Ahmed , bpf@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Meta kernel team Subject: [RFC PATCH 7/7] memcg: no stock lock for cpu hot-unplug Date: Mon, 12 May 2025 20:13:16 -0700 Message-ID: <20250513031316.2147548-8-shakeel.butt@linux.dev> In-Reply-To: <20250513031316.2147548-1-shakeel.butt@linux.dev> References: <20250513031316.2147548-1-shakeel.butt@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Stat-Signature: s89qtmu6k5mo9dgmnjhyfzp4q99fomj7 X-Rspam-User: X-Rspamd-Queue-Id: 82DB3160004 X-Rspamd-Server: rspam06 X-HE-Tag: 1747106090-542157 X-HE-Meta: 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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: List-Subscribe: List-Unsubscribe: Previously on the cpu hot-unplug, the kernel would call drain_obj_stock() with objcg local lock. However local lock was not neede as the stock which was accessed belongs to a dead cpu but we kept it there to disable irqs as drain_obj_stock() may call mod_objcg_mlstate() which required irqs disabled. However there is no need to disable irqs now for mod_objcg_mlstate(), so we can remove the lcoal lock altogether from cpu hot-unplug path. Signed-off-by: Shakeel Butt --- mm/memcontrol.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index af7df675d733..539cd76e1492 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2060,16 +2060,8 @@ void drain_all_stock(struct mem_cgroup *root_memcg) static int memcg_hotplug_cpu_dead(unsigned int cpu) { - struct obj_stock_pcp *obj_st; - - obj_st = &per_cpu(obj_stock, cpu); - - /* drain_obj_stock requires objstock.lock */ - local_lock(&obj_stock.lock); - drain_obj_stock(obj_st); - local_unlock(&obj_stock.lock); - /* no need for the local lock */ + drain_obj_stock(&per_cpu(obj_stock, cpu)); drain_stock_fully(&per_cpu(memcg_stock, cpu)); return 0; -- 2.47.1