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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E8FC1C5DF81 for ; Mon, 24 Aug 2026 14:32:48 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CCAD66B0092; Mon, 24 Aug 2026 10:32:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CA13D6B0096; Mon, 24 Aug 2026 10:32:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BB7846B009B; Mon, 24 Aug 2026 10:32:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 94CCF6B0092 for ; Mon, 24 Aug 2026 10:32:47 -0400 (EDT) Received: from smtpin18.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 13DC4C018B for ; Mon, 24 Aug 2026 14:32:47 +0000 (UTC) X-FDA: 85136404374.18.FC4F04B Received: from mail-yw1-f171.google.com (mail-yw1-f171.google.com [209.85.128.171]) by imf10.hostedemail.com (Postfix) with ESMTP id 3F3BBC000C for ; Mon, 24 Aug 2026 14:32:45 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=google.com header.s=20251104 header.b=IbbChgkA; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf10.hostedemail.com: domain of hughd@google.com designates 209.85.128.171 as permitted sender) smtp.mailfrom=hughd@google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1787581965; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=DObH//Sc3+e2cOll9IRNEEzq8JrLC+/wx5igp55m6yw=; b=Z1cKQkNtwzXN9DC5thW/L2VMWS0dtmKR1nRcMUw7XUUzuB2+uFf60GqMHKS/PajkOBnxwz iKQCXbvbI/4ov3idHm/5Ht8KZT/gQwjZcd2rDj32ZKD9Qjml5PeMBz+m3IWDIaADTsWZeh 43I4Hk9nUpPF58V1Wyjo9PWwSymfk2Y= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=google.com header.s=20251104 header.b=IbbChgkA; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf10.hostedemail.com: domain of hughd@google.com designates 209.85.128.171 as permitted sender) smtp.mailfrom=hughd@google.com ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1787581965; b=OAO7EOF55t7rqoGt3P3de9qvq4nUsAOHo4Jr0/eQcXdZtdoM3dRqQWXHqYUYJV4AimnErX hAdo43/okTknnOW8WUkG+tL9ccAFN2mpuTM+dgECKOAdcOxpYRPW2nZmMb15r4cWww6HW9 5/Xw8KfFhQ14nm4N9m0iv2ZVRqblmuI= Received: by mail-yw1-f171.google.com with SMTP id 00721157ae682-80cebd41372so53715167b3.3 for ; Mon, 24 Aug 2026 07:32:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1787581964; x=1788186764; darn=kvack.org; h=content-type:mime-version:references:message-id:in-reply-to:subject :cc:to:from:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=DObH//Sc3+e2cOll9IRNEEzq8JrLC+/wx5igp55m6yw=; b=IbbChgkAiaX2flPDIOexI4dAO2wxjgEk3rkSlnI8ad4UZpJM8QzmIv0WfF89I3UgD9 16yO3JREJ8Rz7jsND+IA72bgM9MMCLcBjE02jVQADq/iTqlgtT1kwzh1LIeuLTwi0KWc rq2Fdel4XG3+W6HE/XLvi/emRWDCkRQAxuLG18rsFVaAzDHZA5dQ0kMeh0TtJ1YSfaiN GOq8FQKZYF7bHf9bPXHG22eZoA1EEivxtHQ2qZ5IRXiSYbJEs6/JH9cPVvITmuKlJDJy 8jdyNDfczd3nYmL76pXuiuz6iAtypRSHkZujO3H9I9tvpQq/cwTYew5iOw6lwNCRrrRW VfTw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787581964; x=1788186764; h=content-type:mime-version:references:message-id:in-reply-to:subject :cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=DObH//Sc3+e2cOll9IRNEEzq8JrLC+/wx5igp55m6yw=; b=iYrn42MaiOL+sqMajZhRc8w2ScRS1JFdPPhep6xUjOHFXnnCHXpN1QUunzU7HqF4sv gqhdF3RojZahycuswIw/q+DTn0TapOcdRYyyxraMD/Mhe5nwoFdjBeAg8hdpMOm5eM8H /vf9HIq0FDrQ7HydGoThGpykMNdSBt++tOmERkkQsESLPrXcjIRpiR716fPdQpWq922K G/zmpHBiiOYzd0BL1wdh4PUqBVYK7rTvx4gpLeNFrPmjp671ykJkswNpKUVF6sMQlFda gTU4VSq732u+qQ1nnddIpNuPgHNyLOnQKVuyBEV3lQ/UhYvYqk0ufTuPjqdG3IY/fXR0 lOvw== X-Forwarded-Encrypted: i=1; AHgh+Ro495KvKV7VTZpniXZzOVfIvJQerKSKhrebPOU8lThs/WtO1HhTsiGlLKsDT7VpyneiW8REwmEn3w==@kvack.org X-Gm-Message-State: AFuF++nDUQcJdMzYAikOOy91Qz2QQUmrw4Zesev+y7cCb5sLkA5Ci6DZ zzhQjdhuYpreL1t/PT7WF4lm6EuGQFH0IHBcPyzO7qXtzBSOrQeP47lAqhPGrHG58w== X-Gm-Gg: AR+sD11Kfih/Cti7cYdBvS3FZdB2BmyPc+mJABeCeqVWND4coSk6bNuhga53lyg+pzy sis5QVPivdCVpbr63ERPyKQFjnyyvWS7Uc3L5aHHdSB7hpgOjyObKVFxV0ER/vkDGqJziPKXcke lebbQ4sQiRIcLRbzFmRjvrmUrV7j38V5ZweOvBN1Tvw4dGDkc5fstETTNTNMl7RHx9mDwdHoVn9 dxNrWMAjdeBURcnmJYC2rNc5y0xJ8H138MtUg4OhGHNhKKRg2H04yjkpfICJ1SeDYrMuFzzEqzk IT7hJEZY4X1SXzSp5M14pc2Bltkgxe0wrmlxKcceuerFRA4GznArx/sBjaoqTU+IZd5zZ1ZkLRd KzZ3y0G4nW2ACqJC3CTM/B20UN/G15EBe0iyixafu99eY2lcv8KYMTFhRP9XGuuXxiaCdtS0Azi hyorpGM5wY2Mo3FGLkKQJ5RLibS8XOCCeZRuwvg5Ydc9JQohqcceGNsGaveZdZ7XSXkXYoZeb72 fxMf5/WyUW9yOTD3yRLKRSxUt2gr3SU1Tx73l+oKtGIbn6b X-Received: by 2002:a05:690c:ec7:b0:81d:5155:213b with SMTP id 00721157ae682-84c9587c096mr75848627b3.14.1787581963521; Mon, 24 Aug 2026 07:32:43 -0700 (PDT) Received: from darker.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id 00721157ae682-84cac201719sm34583487b3.43.2026.08.24.07.32.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Aug 2026 07:32:42 -0700 (PDT) Date: Mon, 24 Aug 2026 07:32:38 -0700 (PDT) From: Hugh Dickins To: Andrew Morton cc: Ackerley Tng , Alexander Viro , Baolin Wang , Barry Song , Binbin Wu , Christian Brauner , Christoph Hellwig , Christoph Lameter , Claudio Imbrenda , David Hildenbrand , JP Kobryn , Jan Kara , Jens Axboe , Johannes Weiner , Kairui Song , Kiryl Shutsemau , Lance Yang , Leonardo Bras , Lorenzo Stoakes , Marcelo Tosatti , Matthew Wilcox , Mel Gorman , Miaohe Lin , Michal Hocko , Minchan Kim , Muchun Song , Oscar Salvador , Peter Zijlstra , Qi Zheng , Rik van Riel , Sebastian Andrzej Siewior , Shakeel Butt , Suren Baghdasaryan , Vlastimil Babka , Yang Shi , Yu Zhao , Zach O'Keefe , Zi Yan , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 17/25] mm/fbatch: no lru_cache_disable() in __alloc_contig_migrate_range() In-Reply-To: <14a16945-529b-8bc0-ab38-3ea97e54e223@google.com> Message-ID: <614c4116-8326-641e-d7bc-534fde0422b9@google.com> References: <14a16945-529b-8bc0-ab38-3ea97e54e223@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspam-User: X-Stat-Signature: hfprb9jeqp1g8uss8fds8iq49ysx36qq X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 3F3BBC000C X-HE-Tag: 1787581965-331301 X-HE-Meta: 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 o9uFGVHR vEgG7UQdto4xz2MZ3v2w9TwlEn5koafLMh3v4tecLFaDVYSWTy0d+bDqA/SDgHpOsmevk5s/JCem+nrxIU7L+BzWlJB3WQI9Zg1iD7F158FQUuN97XtESpvGI/2DSGGjCMpTzV4i/zOqE0ab2CdXsCeGvG0UUwX0FvIyquyzwBLp+XHiuozz3i0aDsoqxoxmsMp5kQfbWAnyOZRE1AKJ8ASqytdzvtU4woAC1RopARhZpFs+gpawSTR/z+Zh+vQS74wTNIpFW7XA+Y9eXGRaRbHn5AqyyidBXHK/TUgQ4gPHzwT7hunvvAnQPvzg52UJ9xMeFAlQCQND+ebnB4Ua9wvsZL9ACutVIC/LMb+4Dl9nbwXXMM9FLFdmrAIu/uM2c6F4KS0LDvQq7qzoriJ/ZlqeOEkrj6z9t8lJ+w/Mmny56qp2geIi8Dv3EQlo0+9CtdD74QdWmVrHrL0Ysd5C9sdjUhU++zds8fPdO Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Remove lru_cache_disable() from __alloc_contig_migrate_range(). It does not now benefit from lru_add_drain_all() first; and gains little benefit from invalidating buffer head LRUs first, since 5.0 commit 80409c65e2c6 ("mm: migrate: make buffer_migrate_page_norefs() actually succeed"). This will be more controversial. lru_cache_disable()+lru_cache_enable() were brought in for CMA page migration, see 5.13 commit d479960e44f2 ("mm: disable LRU pagevec during the migration temporarily") through 8cc621d2f45d ("mm: fs: invalidate BH LRU during page migration") - I guess the testing there must have been on a 4.19-based Android kernel, without 5.0's buffer_migrate_page_norefs(). It's possible that invalidating BH LRUs perhaps 0 times, perhaps N times, will average out worse than invalidating 1 time and stopping everyone else; or that folio_test_clear_lru() failures manifest more than before (note how folio migration has retries on raised refcount, but isolate_migratepages_block() no retry on failed test_clear_lru). But let's give this a try and look out for regressions. Don't delete lru_cache_disable() yet: leaving stale folio pointers in the per-cpu fbatches, with folio_try_get() yet to come on them, would be bad for memory hotremoval: the lru_cache_disable() in offline_pages() protects from that. Signed-off-by: Hugh Dickins --- mm/page_alloc.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 083cbcb5bdde..96ab51b78a5f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7135,8 +7135,6 @@ static int __alloc_contig_migrate_range(struct compact_control *cc, .reason = MR_CONTIG_RANGE, }; - lru_cache_disable(); - while (pfn < end || !list_empty(&cc->migratepages)) { if (fatal_signal_pending(current)) { ret = -EINTR; @@ -7170,7 +7168,6 @@ static int __alloc_contig_migrate_range(struct compact_control *cc, break; } - lru_cache_enable(); if (ret < 0) { if (!(cc->gfp_mask & __GFP_NOWARN) && ret == -EBUSY) alloc_contig_dump_pages(&cc->migratepages); -- 2.51.0