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 208C4C4167B for ; Tue, 31 Oct 2023 04:58:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3DB5F8D000D; Tue, 31 Oct 2023 00:58:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 364788D0008; Tue, 31 Oct 2023 00:58:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 252F78D000D; Tue, 31 Oct 2023 00:58:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 155C28D0008 for ; Tue, 31 Oct 2023 00:58:01 -0400 (EDT) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id B4127160A1B for ; Tue, 31 Oct 2023 04:58:00 +0000 (UTC) X-FDA: 81404549520.22.84AD720 Received: from out-188.mta0.migadu.com (out-188.mta0.migadu.com [91.218.175.188]) by imf21.hostedemail.com (Postfix) with ESMTP id 991D11C0012 for ; Tue, 31 Oct 2023 04:57:58 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="NJhb/Usj"; spf=pass (imf21.hostedemail.com: domain of chengming.zhou@linux.dev designates 91.218.175.188 as permitted sender) smtp.mailfrom=chengming.zhou@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=1698728279; 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-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=glWEhzZHw9Q8o2NIQUVWc3t/rkBW4T0mk7G578550ZM=; b=4YwkDec9Qjjp1iBUH0u7NFn58C31CWzip0euKPfa+81ekh4GpGo7AuIDH22GTO0tENwXw/ GbEH+tMC9F5eTKCveCjDr3dMP83I7dDpMCmm+JsfY+TqHUdRmKFsyDbSsqK1NTjOahYyjs ymJcjdUNDN2ya5KL757zyLA+H+JLtGw= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1698728279; a=rsa-sha256; cv=none; b=BN3MJj2GYlSQpKHwqWSShUeckik8Vom7/OPgsHndnZPv36mozOKtny2xlyRnHCb2TAVpxL 7S3TMyDdApXx1y3cgkBnxSL0XsjQE23alFSkMS8v506qTLLiakLnIf/Q58puriZbxSU3g2 W0k7WXkiUj8VZYrAsFeydyQiughJT/k= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="NJhb/Usj"; spf=pass (imf21.hostedemail.com: domain of chengming.zhou@linux.dev designates 91.218.175.188 as permitted sender) smtp.mailfrom=chengming.zhou@linux.dev; dmarc=pass (policy=none) header.from=linux.dev Message-ID: <82797556-eb7b-4867-86a1-859d11598fc9@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1698728276; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=glWEhzZHw9Q8o2NIQUVWc3t/rkBW4T0mk7G578550ZM=; b=NJhb/Usj6xad87QL0WNtaCOAmbeXuKQfq+jsoJOwO7gOwL4fogLqIAPnNnjrVQuTZT1AG4 GxP2z/vcct3bhuY5AnRe2M4gD2trbrWGyqpZQmh1kTJxpDrL/ktryO6GrXi4U2Tpb5jev7 2ybIqJFQAOWF3aAXyb4ImbrEcAJD970= Date: Tue, 31 Oct 2023 12:57:23 +0800 MIME-Version: 1.0 Subject: Re: [RFC PATCH v3 0/7] slub: Delay freezing of CPU partial slabs Content-Language: en-US To: Christoph Lameter Cc: vbabka@suse.cz, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Chengming Zhou References: <20231024093345.3676493-1-chengming.zhou@linux.dev> <1199315b-63ce-4be4-8cde-b8b2fd29f91a@linux.dev> <7f70d130-c05a-3cb7-9509-41c21c3014fb@linux.com> <1dcc9969-da5b-4384-96d8-d03c835f198e@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Chengming Zhou In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 991D11C0012 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: wbaaozg3cd4muj5rqaqm9dbpe4f7nc7g X-HE-Tag: 1698728278-579485 X-HE-Meta: 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 GDi8Uwc0 UW0EFuxPJvolQotDhJEzzQ4aULA9Yac6k7e7582TITXUwpqj3LD6kVlwxUhfkNCprfhpLZUTNYqlQDr4weDvhsYktST4EGN3tLz5wCk0NpSyll69mWMfS83ERFeNVkDjyxDuaa5jCq4vRjs0n9cqsEwKqxWboSheXnfHz 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: On 2023/10/31 11:47, Christoph Lameter wrote: > On Tue, 31 Oct 2023, Chengming Zhou wrote: > >> The current scheme (which this series implemented) is: >> >> - node partial slabs: PG_Workingset (set or clear with per-node list_lock protection) >> - cpu partial slabs: !PG_Workingset > > And then the frozen flag needs to be set. Otherwise slab_free() would conclude it is on a partial list? > - cpu partial slabs: !PG_Workingset && !frozen Here comes the optimization that "frozen" is not set for the cpu partial slabs, slab_free() will grab node list_lock then check by !PG_Workingset that it's not on a node partial list. >> - cpu slabs: !PG_Workingset && frozen (set or clear using cmpxchg together with freelist) > > > >> - full slabs: !PG_Workingset > > And frozen is clear? Otherwise it is the same as a cpu partial slab. > Right, - full slabs: !PG_Workingset && !frozen Yes, it's the same as a cpu partial slab from only these two flags, but slab_free() also know whether it was full or not. >> As Vlastimil noted, it's possible to drop "frozen" bit for cpu slabs, but >> we keep it for performance, since we don't need to grab node list_lock to >> check whether PG_Workingset is set or not if the "frozen" bit is set. >> >> Thanks! >>