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 F0C85CCA476 for ; Tue, 7 Oct 2025 22:53:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 38B058E000E; Tue, 7 Oct 2025 18:53:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3141C8E0005; Tue, 7 Oct 2025 18:53:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1B5348E000E; Tue, 7 Oct 2025 18:53:01 -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 031F18E0005 for ; Tue, 7 Oct 2025 18:53:01 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id AA6F0140305 for ; Tue, 7 Oct 2025 22:53:00 +0000 (UTC) X-FDA: 83972820120.17.E42F762 Received: from out-179.mta1.migadu.com (out-179.mta1.migadu.com [95.215.58.179]) by imf23.hostedemail.com (Postfix) with ESMTP id CFD48140002 for ; Tue, 7 Oct 2025 22:52:58 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=lXCJDcLG; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf23.hostedemail.com: domain of roman.gushchin@linux.dev designates 95.215.58.179 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1759877579; 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=+zGrEhn9yIbxrx8akVC6Rjuew94sMfqEV9qMdvVonCg=; b=vYfqqoOD9/Ar+rZGzX4dM0NMwzzGu7swr999mPUr/N/njvL0s5Gem2JWNuNVrANSt5EwBl 06T4UDuEEPIk6rHRMJa+53Z4oYjRwRKy8J/qa/JA35N/4xP//dXFiRbFlIOgI7tqSafugx T6anJCPGTqJClni79T3QsyYi5/h/Lqw= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1759877579; a=rsa-sha256; cv=none; b=axkGazWazmjetJvcg1vHv1mkl9uGXXZRMvQ6wgUoz6sf7eSoR4f/vBFOOgB3FnNHCsyP/Y KAwQMBUcnd94f841BF9DWoKXkWINMfBIQH5ccmZifEsHDKUQc+4Oy7vmKIpcLyv6fMEVJZ YkMxJkbhsXeE7PY1P67jnDSuMa+9xVA= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=lXCJDcLG; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf23.hostedemail.com: domain of roman.gushchin@linux.dev designates 95.215.58.179 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev 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=1759877576; 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: in-reply-to:in-reply-to:references:references; bh=+zGrEhn9yIbxrx8akVC6Rjuew94sMfqEV9qMdvVonCg=; b=lXCJDcLGRCwwkU7jnZ6bJv2a3MjwgazcrxC0yJDKX0uEgsGEiDtW8vVSPksXSB0lOUih7r wYcsqQKVxqBhyasR8cNmnFe5KxrJnjYHEonk2ybtQeg1pM1/fxvhkoV16ih1XjUDmeKkRV xPToa6kJLGuv9CFDOcW6yEQpU37guAg= From: Roman Gushchin To: Andrew Morton Cc: linux-kernel@vger.kernel.org, "Matthew Wilcox (Oracle)" , Jan Kara , Dev Jain , linux-mm@kvack.org Subject: Re: [PATCH v3] mm: readahead: make thp readahead conditional to mmap_miss logic In-Reply-To: <20251007153424.1b46a4018e17d5dafd7fb126@linux-foundation.org> (Andrew Morton's message of "Tue, 7 Oct 2025 15:34:24 -0700") References: <20251006175106.377411-1-roman.gushchin@linux.dev> <20251007153424.1b46a4018e17d5dafd7fb126@linux-foundation.org> Date: Tue, 07 Oct 2025 15:52:49 -0700 Message-ID: <87play1fzy.fsf@linux.dev> MIME-Version: 1.0 Content-Type: text/plain X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam01 X-Stat-Signature: 416rgpdum3azuyntu36shp9mfzumiqi8 X-Rspam-User: X-Rspamd-Queue-Id: CFD48140002 X-HE-Tag: 1759877578-213528 X-HE-Meta: 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 0Yf5Z6nW oT9D95ZVofo3DMIpHZ3weBsydMVWtMkuNSMRb+yH4YmNTo2xdkZO80ydsZCULKZpcbIiD6ZT8RP8Weq95lzhZ9NJaCa5ect7vfk7selS67K9Smq0B1hu+c8mOQ97sXBSWl4VTIxqGvAxOIZlamkxqZ49rkNMs3Ss6xPY6Xzmwik0L8zKkwxlhA2HlY9hKfuO0gE0IbVqyOsuOZWobC4RLqbT5/tiXcMuX/PdPJ8KupmCUWP8aNY9XMSVZYA1rFT70bKrziKaEv5GvtdHYb/k7YAQ1PFFlL6YYe1Qaf/oxJsL6yAbQ/+NWmXUwMwj9wXRo1IWg3alw6P1kOJDofS75M9q4xnjIxGr8cPCCTCssR0rlZCdUBkLYWxtn9hV9nxf/hI4J 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: Andrew Morton writes: > On Mon, 6 Oct 2025 10:51:06 -0700 Roman Gushchin wrote: > >> Commit 4687fdbb805a ("mm/filemap: Support VM_HUGEPAGE for file mappings") >> introduced a special handling for VM_HUGEPAGE mappings: even if the >> readahead is disabled, 1 or 2 HPAGE_PMD_ORDER pages are >> allocated. > > Three years ago. > >> This change causes a significant regression > > So no backport suggested? I guess reasonable given how long 4687fdbb805a has > been in tree. Yes, this was my thinking. Also you need a very specific setup to reveal this regression. >> Signed-off-by: Roman Gushchin >> Cc: Matthew Wilcox (Oracle) >> Cc: Jan Kara >> Cc: Dev Jain > > But I'll slap the Fixes: in there, it might help someone. I'd do exactly what you suggested: Fixes + no stable backport. But I guess it still might end up in the LTS tree thanks to the automation picking up all fixes. Should be ok too. Thanks!