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 1903CC3ABC5 for ; Wed, 14 May 2025 05:09:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1A7506B00CB; Wed, 14 May 2025 01:09:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0E2816B00CD; Wed, 14 May 2025 01:09:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E753A6B00CE; Wed, 14 May 2025 01:09:03 -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 C5FE66B00CB for ; Wed, 14 May 2025 01:09:03 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id D4DF7C04A9 for ; Wed, 14 May 2025 05:09:03 +0000 (UTC) X-FDA: 83440334166.13.8099978 Received: from out-173.mta0.migadu.com (out-173.mta0.migadu.com [91.218.175.173]) by imf27.hostedemail.com (Postfix) with ESMTP id 22FF540005 for ; Wed, 14 May 2025 05:09:01 +0000 (UTC) Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=C+de8KGJ; spf=pass (imf27.hostedemail.com: domain of shakeel.butt@linux.dev designates 91.218.175.173 as permitted sender) smtp.mailfrom=shakeel.butt@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1747199342; 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=0h+SN0UhJ+eLym9lbXu/RGEYZMj+86zExOIBnbok3mA=; b=ggBAHfRGPubw9tELIK4hBIRLngbWwtGj1iWYJk21iqi0+0WsFBm1B9aTLZDzJ8bqIfHc/F 73LBtS4GrbHNJBSXzJHGDCQN8cHEceWn5pvF0lxBUwcHPUfG+TfwPmwIVvwSlzl4OXeGMc OYswc73gS2gg0Rb35mKlqlYWfPVER4g= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=C+de8KGJ; spf=pass (imf27.hostedemail.com: domain of shakeel.butt@linux.dev designates 91.218.175.173 as permitted sender) smtp.mailfrom=shakeel.butt@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1747199342; a=rsa-sha256; cv=none; b=qP1iEYp8+fa9CUz2lK0pfh1LzVhLKK5BmWshjLV8rCsrdDfXaltto5gvCISD3E7lWRoLta OfKllICYt5+oMyECj8NNANEUnQETY9O/QJ1ysQlkHFAfSh45e0C2Rsmhz5oxOZMGGtmg6c WSpihcOTzccQuB8ldygBKcaV9A5ka/4= 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=1747199340; 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=0h+SN0UhJ+eLym9lbXu/RGEYZMj+86zExOIBnbok3mA=; b=C+de8KGJN9lp4gQRHrHBI4K2deILhvh8eDjt9b1qW70ETe92jGJ2G5ft+1/TLBJgvvo4Sd 3pF9fDgCGR+Z/uYwP3bFGBQuZQlsqVAZzIuwh1FO4zcThO9kM6mtyAhaDxufaU23KbGCk/ DQHrlLHfhbKtrkK0/btvhoPSRjJlSEQ= 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: [PATCH 6/7] memcg: no stock lock for cpu hot-unplug Date: Tue, 13 May 2025 22:08:12 -0700 Message-ID: <20250514050813.2526843-7-shakeel.butt@linux.dev> In-Reply-To: <20250514050813.2526843-1-shakeel.butt@linux.dev> References: <20250514050813.2526843-1-shakeel.butt@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Queue-Id: 22FF540005 X-Rspamd-Server: rspam09 X-Stat-Signature: tqfddsextcixarmrozy4ufecp1kany35 X-HE-Tag: 1747199341-975638 X-HE-Meta: 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 83tB+7JB QTrBjg+S+EX4I5/TK9Rso+8L9CuE6sHgGH3Lq6PHD2iGH3B0M2zVIHLbQEu/Uqk0UVk1tq0kJDMPYL/oI+rBY4YAUK6arEGF9cTET+RWj18yDns+tJEGOzITdKjgINJHPJHMoteDfo1TXGpC/D3daxfWmhzBAkN0MwZgW18XUghrQfqo= 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 needed 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 local lock altogether from cpu hot-unplug path. Signed-off-by: Shakeel Butt Acked-by: Vlastimil Babka --- mm/memcontrol.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 4f19fe9de5bf..78a41378b8f3 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2050,17 +2050,8 @@ void drain_all_stock(struct mem_cgroup *root_memcg) static int memcg_hotplug_cpu_dead(unsigned int cpu) { - struct obj_stock_pcp *obj_st; - unsigned long flags; - - obj_st = &per_cpu(obj_stock, cpu); - - /* drain_obj_stock requires objstock.lock */ - local_lock_irqsave(&obj_stock.lock, flags); - drain_obj_stock(obj_st); - local_unlock_irqrestore(&obj_stock.lock, flags); - /* 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