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 A1305EE57C8 for ; Wed, 31 Dec 2025 02:51:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 145416B0089; Tue, 30 Dec 2025 21:51:18 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 127046B008A; Tue, 30 Dec 2025 21:51:18 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0324B6B008C; Tue, 30 Dec 2025 21:51:17 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id E5C4E6B0089 for ; Tue, 30 Dec 2025 21:51:17 -0500 (EST) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id AF3EDC1D84 for ; Wed, 31 Dec 2025 02:51:17 +0000 (UTC) X-FDA: 84278239794.29.3F3A94D Received: from mail-ej1-f47.google.com (mail-ej1-f47.google.com [209.85.218.47]) by imf14.hostedemail.com (Postfix) with ESMTP id B26FE100002 for ; Wed, 31 Dec 2025 02:51:15 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=G53L+2We; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf14.hostedemail.com: domain of richard.weiyang@gmail.com designates 209.85.218.47 as permitted sender) smtp.mailfrom=richard.weiyang@gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1767149475; a=rsa-sha256; cv=none; b=Y7XZti3U68zmfQ9Wk22BQoCbGJCr9AYAkWZ9lvMZ18UznkraEuu3sb9Sk5ci3F8y1k0t11 Nt7Ehh5fLY+Al/G86+UbjLPuqnPR6Y/YaB+yuCvBqNqS2H6VJtoIqkaBFx/ULyNs2KAbJh 0Dk4jidamvpTBx3Jvc2sM9KWje0ZuVI= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=G53L+2We; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf14.hostedemail.com: domain of richard.weiyang@gmail.com designates 209.85.218.47 as permitted sender) smtp.mailfrom=richard.weiyang@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1767149475; h=from:from:sender:reply-to: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=EmlhgLzDihwQXJKjPLEsbonM6eB7pTCajPhK6zvZfAY=; b=Bbpt3SgQ86I+Cq7MuKiLWCadvqsF7v9d+uk9C5IoyFoYtERSoN3U4yJBf/P2o113QsE8Fm ru+KMmfmB7KRYVjvOfJTrnrr50yRRjwgsxUqVYPTpirvyeKeCSrrqdQ/sPOXSkNvY5SuFX nc/2WDBOtUgv7EFjNx6LMirX51T8G8Y= Received: by mail-ej1-f47.google.com with SMTP id a640c23a62f3a-b76b5afdf04so1575932566b.1 for ; Tue, 30 Dec 2025 18:51:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1767149474; x=1767754274; darn=kvack.org; h=user-agent:in-reply-to:content-disposition:mime-version:references :reply-to:message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=EmlhgLzDihwQXJKjPLEsbonM6eB7pTCajPhK6zvZfAY=; b=G53L+2Wesktw8eKyz+bNGOe4OxXIfgcAkmwPbN0bYri+dLnVxUDLc8mFmS39W6yGUv natEO19TqWbbJK61C3iD/hY1sxzhWeZhC4SQPfrr5FgqpX3QcpuE4H0xm1dSV6QX4mwp mhA0r9azsWZ2+/IQYiVa7SlEgSW5o1Ks3FcudvyBAjQw1azCX/807/8fr2j9EnMYim/c MzQ7d4YpuUYp4j8oP/RhywuWsVhavTA/O3SG9c7bTQj8yXa6VzyyhmBC8/mHb7uyXSfQ 5VAK/i7s6+za8UkvqjRAGHA9b/Lx2buQHHTF789sitXYs8vDNlPGm8/zCamNPo3eIjbu rBLQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767149474; x=1767754274; h=user-agent:in-reply-to:content-disposition:mime-version:references :reply-to:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=EmlhgLzDihwQXJKjPLEsbonM6eB7pTCajPhK6zvZfAY=; b=sC4DSimDCTpqSjbHEPJe/rNYzMnDao7Cn0qUe+mkDsjmmkYsIq+mTD8bR1HyFUCU7W w5SNKR+et/RoLud8IL58VuedyaXwBFAWksitOIN6LOV146pmf50fvqEJ9HqSnb5c/9pH xO6PTh83d20QxFzZklIvEyYqIzDORRNc6azh9KG6KAecyHEWYWNK4Mmspx2rgHEPInOw i8FAKAOTqOiX0Hrgij5Apr/V1e1bv8kiLtymjcalw7ojA6uXbbCzBsZV/VlJhSv4vA0S 7NZSYqIMoYbzpxCfI8GFkl9sRfJOBmLbuWH2piqdCnN6afFJUxSvVN9xkg78YoFNxey8 OPQA== X-Forwarded-Encrypted: i=1; AJvYcCWMdbi5jbCtwSjLsA6iq8BrZwmLiX2vViGlK96MRKvvwX00Z3jW+v/YPbE2Kp6bHm/qYTr+UzkORA==@kvack.org X-Gm-Message-State: AOJu0YwK6ovERKe4HbhW2/C8PGpHQnG6wvMX+SfgnVS9T6o0AHmycnWE s7b6OpmsYOEiV0Ss8RXFUwUk4zZLVRQixj7OjKccozeao3+WioMw8EoC X-Gm-Gg: AY/fxX4cWf21mNwutP3ywFBAJDUivjT3arx+svNA+gNdtD+4NgfcJhHEFBfNC5fQvm4 dftAKMs2CMnIXTXbiCsINDVfT1fY7y9UOVMijSFk6fE+Vf9t4Ot1FflREUDNtVuoKEzT9IxiOrL ByP/50IhmXFzw1tpfmLaai3TCJPmiIT+OMgVsQnBaex7YMyeVoUFLpEkvLq+YwCnaPx1fg8DFiR wAIImRgMmfWtG3WzS5lc/oVVPndMZQP03k73ml4bWsGWXBOVemCPY3Zap3tHUO1BQjWs9DWTqjE m7GvaXZ1E/RJSIsczFhKEV+j4fBeV//wT+JrNR8xz02q3sCcd78omcg5rMTNMgOwSh3Y8xhqLZ9 /uXqF0Io9neHKDHF0jFgT+ir+sniEAjPnniAlFwN6hz+TwLudrfkDGLCxgMyrgCqALHDTdj/HiN Hfi9l4QD3CGZe8HDcifeK/ X-Google-Smtp-Source: AGHT+IGVcLZdqj6eNaasrn746ipTYI7fDfRCvu0V+Z1Q5bofYsJUvEoTAObsuEDApPDu/anBTFxEKA== X-Received: by 2002:a17:906:5a68:b0:b83:9751:4334 with SMTP id a640c23a62f3a-b839751755fmr285999566b.50.1767149473783; Tue, 30 Dec 2025 18:51:13 -0800 (PST) Received: from localhost ([185.92.221.13]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b8037f511fesm3867530466b.65.2025.12.30.18.51.13 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Tue, 30 Dec 2025 18:51:13 -0800 (PST) Date: Wed, 31 Dec 2025 02:51:12 +0000 From: Wei Yang To: "David Hildenbrand (Red Hat)" Cc: Vernon Yang , akpm@linux-foundation.org, lorenzo.stoakes@oracle.com, ziy@nvidia.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, richard.weiyang@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vernon Yang Subject: Re: [PATCH v2 4/4] mm: khugepaged: set to next mm direct when mm has MMF_DISABLE_THP_COMPLETELY Message-ID: <20251231025112.uzlgrs3dgbyzul2x@master> Reply-To: Wei Yang References: <20251229055151.54887-1-yanglincheng@kylinos.cn> <20251229055151.54887-5-yanglincheng@kylinos.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: B26FE100002 X-Stat-Signature: f5ayetztcy1ysgnrnz4hcps4nqrqykhy X-HE-Tag: 1767149475-871028 X-HE-Meta: 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 UWapcu8s 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 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 Tue, Dec 30, 2025 at 09:03:23PM +0100, David Hildenbrand (Red Hat) wrote: >On 12/29/25 06:51, Vernon Yang wrote: >> When an mm with the MMF_DISABLE_THP_COMPLETELY flag is detected during >> scanning, directly set khugepaged_scan.mm_slot to the next mm_slot, >> reduce redundant operation. >> >> Signed-off-by: Vernon Yang >> --- >> mm/khugepaged.c | 9 +++++++-- >> 1 file changed, 7 insertions(+), 2 deletions(-) >> >> diff --git a/mm/khugepaged.c b/mm/khugepaged.c >> index 2b3685b195f5..72be87ef384b 100644 >> --- a/mm/khugepaged.c >> +++ b/mm/khugepaged.c >> @@ -2439,6 +2439,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result, >> cond_resched(); >> if (unlikely(hpage_collapse_test_exit_or_disable(mm))) { >> + vma = NULL; >> progress++; >> break; >> } > >I don't understand why we need changes at all. > >The code is > > mm = slot->mm; > /* > * Don't wait for semaphore (to avoid long wait times). Just move to > * the next mm on the list. > */ > vma = NULL; > if (unlikely(!mmap_read_trylock(mm))) > goto breakouterloop_mmap_lock; > > progress++; > if (unlikely(hpage_collapse_test_exit_or_disable(mm))) > goto breakouterloop; > > ... > >So we'll go straight to breakouterloop with vma=NULL. > >Do you want to optimize for skipping the MM if the flag gets toggled >while we are scanning that MM? > >Is that really something we should be worrying about? > >Also, why can't we simply do a > >diff --git a/mm/khugepaged.c b/mm/khugepaged.c >index 97d1b2824386f..af8481d4b0f4e 100644 >--- a/mm/khugepaged.c >+++ b/mm/khugepaged.c >@@ -2516,7 +2516,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result, > * Release the current mm_slot if this mm is about to die, or > * if we scanned all vmas of this mm. > */ >- if (hpage_collapse_test_exit(mm) || !vma) { >+ if (hpage_collapse_test_exit_or_disable(mm) || !vma) { > /* > * Make sure that if mm_users is reaching zero while > * khugepaged runs here, khugepaged_exit will find > This one looks better. But the sad thing is we can't remove this mm from scan list, since user may toggle this flag later. > >-- >Cheers > >David -- Wei Yang Help you, Help me