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 A18FBC2A062 for ; Mon, 5 Jan 2026 02:10:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 02E6D6B00C2; Sun, 4 Jan 2026 21:10:01 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id F1EA46B00C3; Sun, 4 Jan 2026 21:10:00 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E4B816B00C4; Sun, 4 Jan 2026 21:10:00 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id D46356B00C2 for ; Sun, 4 Jan 2026 21:10:00 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 92C37161D15 for ; Mon, 5 Jan 2026 02:10:00 +0000 (UTC) X-FDA: 84296279760.19.A0CBD17 Received: from out-172.mta1.migadu.com (out-172.mta1.migadu.com [95.215.58.172]) by imf12.hostedemail.com (Postfix) with ESMTP id 8F6A040002 for ; Mon, 5 Jan 2026 02:09:58 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=hc1DzIWl; spf=pass (imf12.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.172 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1767578999; a=rsa-sha256; cv=none; b=Xk++R9KX8n4SeurIUsT37kTHn33yEtDGrLtzOM/ipiQOwZgmJDpDLIaHrzcWUZ4LKIsYoD ff60M/GNUpcw2pzlBt9AeG/dzp2U7rpawjHCohVpwFAfmB8HtOGkBAJ8EagOUWjG+7GpeM stgChP463BvkURS6fcUVMrUA8WOfnZI= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=hc1DzIWl; spf=pass (imf12.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.172 as permitted sender) smtp.mailfrom=lance.yang@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=1767578998; 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=gNRGv23p5K6B6+hbFqyk7acP1QElSBybPClHvzoXsN4=; b=PvpUoxPaznNL9JEwd0NyU7gb9bU9rFl/AB5vnAV33qY0p+fPHpPa3BbVcJgNnXsqJiYREc ynhmQijv/A23e0HIcvTipcYHZmfye8XdTIQD56a1zjXIc1kFf3iMKuMyQiHI3D2S3/xryf s7axvZRwqgFWjxprRM4kxAT7O6qorV4= Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1767578996; 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=gNRGv23p5K6B6+hbFqyk7acP1QElSBybPClHvzoXsN4=; b=hc1DzIWlNRpdtkcj5GBA2EPwYztubu8pdn+LfsS+7LACW29MMqI+9MgKLvh0mHdjDEQ1X1 Tmkvd35wV+0LIit+Kx56sEI6nr5pQYF7f9VhZSYDAAgVZgI+2p5ESO5F7gj/u4BapZYXY/ IxRBmmxu2jN8SqALKVsvEaDFwIUmb68= Date: Mon, 5 Jan 2026 10:09:43 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v3 6/6] mm: khugepaged: set to next mm direct when mm has MMF_DISABLE_THP_COMPLETELY Content-Language: en-US To: Wei Yang Cc: Vernon Yang , lorenzo.stoakes@oracle.com, ziy@nvidia.com, dev.jain@arm.com, baohua@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, david@kernel.org, Vernon Yang , akpm@linux-foundation.org References: <20260104054112.4541-1-yanglincheng@kylinos.cn> <20260104054112.4541-7-yanglincheng@kylinos.cn> <20260105003128.7xitfioeno56h7f3@master> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Lance Yang In-Reply-To: <20260105003128.7xitfioeno56h7f3@master> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Queue-Id: 8F6A040002 X-Rspamd-Server: rspam04 X-Stat-Signature: grjmxk96hwjzsku3e6f81m95xjoxdky4 X-HE-Tag: 1767578998-542440 X-HE-Meta: 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 ZRkVAoSo ydmPIitIJ+Bc+w+VqRcBhLviTrKdOjPbGdJxqIbMS8EWBzBE30J7YrRe6BouzuYA1myNgXMSghYVBOvCwUNhyv8UCikUGNDK3MZD66GkXk6hoXBqUgf0r2LAplQjqwxfyxqfL9XqQ8aeWabW6SVtqpSghGGNpdyXzYIJ2ySEkah72eJNXW8HiU8MDgODa5SBfdzgTdouMU69zzvlVA956vbb11n+LOU6lNk8gLFsZXOvYFt4MQ7wX8xnqC7m7ZAEJvFGMk448rrr7qNFtYE9zNUTt0xWVjkrH7LiH 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 2026/1/5 08:31, Wei Yang wrote: > On Sun, Jan 04, 2026 at 08:20:29PM +0800, Lance Yang wrote: >> >> >> On 2026/1/4 13:41, 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 | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/mm/khugepaged.c b/mm/khugepaged.c >>> index 1ca034a5f653..d4ed0f397335 100644 >>> --- a/mm/khugepaged.c >>> +++ b/mm/khugepaged.c >>> @@ -2541,7 +2541,7 @@ 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 >> >> >> Let's convert hpage_collapse_test_exit() in collect_mm_slot() as well, >> otherwise the mm_slot would not be freed and will be scanned again ... >> >> static void collect_mm_slot(struct mm_slot *slot) >> { >> struct mm_struct *mm = slot->mm; >> >> lockdep_assert_held(&khugepaged_mm_lock); >> >> if (hpage_collapse_test_exit(mm)) { <- >> > > What if user toggle the MMF_DISABLE_THP_COMPLETELY flag again? Maybe it's fine :) If user sets MMF_DISABLE_THP_COMPLETELY, they probaly would not clear it soon. Keeping the slot wastes memory. If they do clear it later, page faults will trigger do_huge_pmd_anonymous_page() -> khugepaged_enter_vma(), which re-adds the mm. Anyway, no strong opinion on that. > >> hash_del(&slot->hash); >> list_del(&slot->mm_node); >> >> mm_slot_free(mm_slot_cache, slot); >> mmdrop(mm); >> } >> } >