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 55E15C3DA7F for ; Mon, 12 Aug 2024 09:40:48 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A36866B008C; Mon, 12 Aug 2024 05:40:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9E5CF6B0098; Mon, 12 Aug 2024 05:40:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8D3DA6B009A; Mon, 12 Aug 2024 05:40:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 743156B008C for ; Mon, 12 Aug 2024 05:40:47 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id E633A409AE for ; Mon, 12 Aug 2024 09:40:46 +0000 (UTC) X-FDA: 82443098892.21.AB015A2 Received: from out-189.mta1.migadu.com (out-189.mta1.migadu.com [95.215.58.189]) by imf23.hostedemail.com (Postfix) with ESMTP id 0200B140007 for ; Mon, 12 Aug 2024 09:40:44 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=folFWAZg; spf=pass (imf23.hostedemail.com: domain of muchun.song@linux.dev designates 95.215.58.189 as permitted sender) smtp.mailfrom=muchun.song@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=1723455575; 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=rduprgBSIee4d5b5yYCJc0UYqXaYrohaT8GPx1gGph8=; b=ZBs1A6qbjqxPckz9pGxhIBknO+mR12YWJoIvteyhx74etGzLbb+41O2ALfFeFo9IBacyPw IeKVsJ3HdWqO1AfQ7gwbYs3k2+8fJDgIdIstdt5e52hvLoSENCDaGpbpRmfL/VOAmAw0Dk VRsEl+puEJ0ojeKdkREbCvuut3nzG2Q= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1723455575; a=rsa-sha256; cv=none; b=lIvEOen6E1Z1SJqyn4qZrHE45TieOWtcWkIXI3ipTIIGYM3xcrMBJhN93bwIPFKh2YpfEv xRGBMHIyMqtg3fVds5+Bcl3sgBwmmI2xTsoPGOWL8aD+b+RYz8QwnJCpbzxLrbNRuFQRlJ w5wpiaSDbA3xqjBgufWyDDfqorBxE/k= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=folFWAZg; spf=pass (imf23.hostedemail.com: domain of muchun.song@linux.dev designates 95.215.58.189 as permitted sender) smtp.mailfrom=muchun.song@linux.dev; dmarc=pass (policy=none) header.from=linux.dev Content-Type: text/plain; charset=us-ascii DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1723455642; 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=rduprgBSIee4d5b5yYCJc0UYqXaYrohaT8GPx1gGph8=; b=folFWAZghelTqknVmC7q+srlY79ynMWX+5BWYoO8tvRCihniH7E2MOOB2fkhqlupH+na3G TB0tbAwB0qgOHS6sxVB5N77RuAyjK5qRnu7qgvt7E1VpveM000Y7+p1Wx9GZEaDfDaNQKL ZvIIZ6BbMVz7nlo5rkHkDQ08LpO06nQ= Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3774.600.62\)) Subject: Re: [PATCH mm-unstable v1] mm/hugetlb_vmemmap: batch HVO work when demoting X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Muchun Song In-Reply-To: <20240811041703.2775153-1-yuzhao@google.com> Date: Mon, 12 Aug 2024 17:40:02 +0800 Cc: Andrew Morton , Linux Memory Management List , linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <20240811041703.2775153-1-yuzhao@google.com> To: Yu Zhao X-Migadu-Flow: FLOW_OUT X-Stat-Signature: h7i5p8143iowkqx5ptj7go7o6nw4yrwa X-Rspamd-Queue-Id: 0200B140007 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1723455644-568929 X-HE-Meta: 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 dGTt10r5 FWUaF5KTYIK6WbIE61dkaSEZnf2q8yLzvbBoEyhRqHNMksfbPsvxKO5aQEDp82QF2puSWyofKAHeqGvo6v0nVy3VIXjOOVPdtOuwl8rA4lIRQ7cW2IhspWgaguV9sX/xM3YDdy70LN0NJtFejKrWqWfERWNfZ5qRKbH1XBvgcHsbZHQT7QJMxxMR63Uu6ZcQW8VJUo2pGm8GAB89brJaIgxECh9oFUcXIMusK 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 Aug 11, 2024, at 12:17, Yu Zhao wrote: >=20 > Batch the HVO work, including de-HVO of the source and HVO of the > destination hugeTLB folios, to speed up demotion. >=20 > After commit bd225530a4c7 ("mm/hugetlb_vmemmap: fix race with > speculative PFN walkers"), each request of HVO or de-HVO, batched or > not, invokes synchronize_rcu() once. For example, when not batched, > demoting one 1GB hugeTLB folio to 512 2MB hugeTLB folios invokes > synchronize_rcu() 513 times (1 de-HVO plus 512 HVO requests), whereas > when batched, only twice (1 de-HVO plus 1 HVO request). And > performance between the two cases are significantly different, e.g., > echo 2048kB >/sys/kernel/mm/hugepages/hugepages-1048576kB/demote_size > time echo 100 >/sys/kernel/mm/hugepages/hugepages-1048576kB/demote >=20 > Before this patch: > real 8m58.158s > user 0m0.009s > sys 0m5.900s >=20 > After this patch: > real 0m0.900s > user 0m0.000s > sys 0m0.851s >=20 > Fixes: bd225530a4c7 ("mm/hugetlb_vmemmap: fix race with speculative = PFN walkers") > Signed-off-by: Yu Zhao Reviewed-by: Muchun Song Thanks.