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 B705DC4332F for ; Tue, 31 Oct 2023 02:51:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 48C7E6B02A1; Mon, 30 Oct 2023 22:51:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 414106B02A2; Mon, 30 Oct 2023 22:51:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2B54D6B02A3; Mon, 30 Oct 2023 22:51:08 -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 0F3946B02A1 for ; Mon, 30 Oct 2023 22:51:08 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id DF37E1A0939 for ; Tue, 31 Oct 2023 02:51:07 +0000 (UTC) X-FDA: 81404229774.18.91D5F8E Received: from out-186.mta1.migadu.com (out-186.mta1.migadu.com [95.215.58.186]) by imf08.hostedemail.com (Postfix) with ESMTP id DCAAC160021 for ; Tue, 31 Oct 2023 02:51:05 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=DaUqksiP; spf=pass (imf08.hostedemail.com: domain of chengming.zhou@linux.dev designates 95.215.58.186 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=1698720666; 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=sJGocIrvJOpdyaBLIvTHhgCm+KI16lXmHvQhyhxns3g=; b=X/GzpTXg5zpQ4OePIRboB1Swwd5vgIXPYjKDc/s0PlhsPLeOJ1xwVTW0Th84OWG05bj3fk TtfkgGR5sKhf0N2Oz8REv+EnD2DCzq5uDXy7+bGbIcNWLlUk2jjEdW8nosmpSs5tjOMkKH nD4DCDH09MWSrRzwUwmSB0wtkiJMy1o= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1698720666; a=rsa-sha256; cv=none; b=dnW9g8OHQ4gPywE+hsjurjKTsvt8E9Z20GuEKoBohKTrYqr31nuSSXeQP1YCsL6cXIRylf nAiDRfmcch10iLTnF2Gc8CX99VeuM3vdPl0b32FbLBNG1oULOVNRu6beAwkLKX33g+0fb5 91raFqxYa5fMITWdBRVoKFQzd8cIR2I= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=DaUqksiP; spf=pass (imf08.hostedemail.com: domain of chengming.zhou@linux.dev designates 95.215.58.186 as permitted sender) smtp.mailfrom=chengming.zhou@linux.dev; dmarc=pass (policy=none) header.from=linux.dev Message-ID: <1dcc9969-da5b-4384-96d8-d03c835f198e@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1698720663; 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=sJGocIrvJOpdyaBLIvTHhgCm+KI16lXmHvQhyhxns3g=; b=DaUqksiPCxsm2P165op2FK7Z8jYJPEvUwhHu13OegGDh0aU+2Tiwtn57XudzehhMgoy8UP U8AQyOlzpM2iuBqadciwZOGw1uL+zJ+Ff+tWhoRJkd9utrVWeNs0dpamyA6/eApsWZlxwe Lbsc9oPhgDPuaSRlZzVNAb6sVtZuBZY= Date: Tue, 31 Oct 2023 10:50:33 +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 , vbabka@suse.cz Cc: 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> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Chengming Zhou In-Reply-To: <7f70d130-c05a-3cb7-9509-41c21c3014fb@linux.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: DCAAC160021 X-Rspam-User: X-Stat-Signature: 1ub99uzfb8afodpp8ghdde9ukmrk9re6 X-Rspamd-Server: rspam03 X-HE-Tag: 1698720665-863748 X-HE-Meta: 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 4CP2Z0LS Qw/SRYHsmAyZo11oPG7y0S3qCYtqDAD00bj2lCjRjU9IU8Jo42XOKc4UzRMCqF0Kr4zDPb7sXs7wFzL3Zu1wWiirEMCsNEV6mWmzMDRM2ed2zgh6KolQ8md1J08g55uZ9ppnP+agkVEZOtwb95zZOSoH/jLOkY4QfYjdW 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 03:25, Christoph Lameter wrote: > On Sat, 28 Oct 2023, Chengming Zhou wrote: > >> 2. But for full slab (slab->freelist == NULL), PG_workingset is not much useful, we don't >>   safely know whether it's used as the cpu slab or not just from this flag. So __slab_free() >>   still rely on the "frozen" bit to know it. >> >> 3. And the maintaining of "frozen" has no extra cost now, since it's changed together with "freelist" >>   and other counter using cmpxchg, we already have the cmpxchg when start to use a slab as the cpu slab. >> >> Maybe I missed something, I don't know how to drop the frozen flag. > > > Maybe frozen is now = PG_Workingset | cmpxchg-frozen? > > 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 - cpu slabs: !PG_Workingset && frozen (set or clear using cmpxchg together with freelist) - full slabs: !PG_Workingset 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!