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 44047CD342F for ; Wed, 6 May 2026 02:05:48 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 650A86B0005; Tue, 5 May 2026 22:05:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6284D6B0088; Tue, 5 May 2026 22:05:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 565286B008A; Tue, 5 May 2026 22:05:47 -0400 (EDT) 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 463336B0005 for ; Tue, 5 May 2026 22:05:47 -0400 (EDT) Received: from smtpin05.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay04.hostedemail.com (Postfix) with ESMTP id CB6E31A06C5 for ; Wed, 6 May 2026 02:05:46 +0000 (UTC) X-FDA: 84735353892.05.9140AE0 Received: from out-184.mta0.migadu.com (out-184.mta0.migadu.com [91.218.175.184]) by imf26.hostedemail.com (Postfix) with ESMTP id E0603140002 for ; Wed, 6 May 2026 02:05:44 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="eu/LWEgQ"; spf=pass (imf26.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.184 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=1778033145; 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=zooTfGMwgUxut9TmF4UJ+R+H7n0OixPbclu6PSkIssg=; b=aPktQY5zXdyTaiviwrc4QLmMQBQHnnSscDSMw4fceWAXJ0q2QlZtgxRRV2H3XaiTIc4VP2 QobjsfCRWBLy4FlL22Tqy7MtI+2Ds1r+iSIkSubWnVbhpUZuyUzMLqLIGp5G3ji+UC66aJ E7a3gmaPgbDHWrFc1Z/4KGooVoZHqec= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="eu/LWEgQ"; spf=pass (imf26.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.184 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=1778033145; a=rsa-sha256; cv=none; b=6WaqXU1n7Lmc4EIyQrHW/5KFOdO1MSPXW6vBBb3q4UzSXDZzTdyGR/LO2bGjXbK7/M3xI2 08O6a/7vAq7esdrkVKayE/FRZrOOViW/E2ZAYevPD0FHrbfE783/e/MmOjLZmBlAyFP3lN CMure0F0dNs5OuNinf/IzE4f5vOnAZQ= 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=1778033142; 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=zooTfGMwgUxut9TmF4UJ+R+H7n0OixPbclu6PSkIssg=; b=eu/LWEgQw6ybfH8JF0ngSDLBvaXrPp5zsR17NGm7LzHNtl89Hb8Lcr/0MHYl5ZFwaTB87d flzL4HqrESimXgWbHdfqfwpsDwLMyXZRWgX+7ka4N2JESxia03E6sEj6YAxEL4KSt3n/at dBJl7dIUW3E+ZJT6EfGdqa1i23sicmQ= From: Lance Yang To: ye.liu@linux.dev Cc: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, xhao@linux.alibaba.com, liuye@kylinos.cn, ziy@nvidia.com, baolin.wang@linux.alibaba.com, liam@infradead.org, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, akpm@linux-foudation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm/khugepaged: clear MMF_VM_HUGEPAGE on mm_slot_alloc() failure Date: Wed, 6 May 2026 10:05:26 +0800 Message-Id: <20260506020526.18953-1-lance.yang@linux.dev> In-Reply-To: <20260506012130.9306-1-ye.liu@linux.dev> References: <20260506012130.9306-1-ye.liu@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: E0603140002 X-Stat-Signature: jctwpmf1n7jfpcgu7yfxeypwykz3cuoz X-HE-Tag: 1778033144-651144 X-HE-Meta: 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 PC6HCRbX nbrOlfVp4Bl0cw3HM92587PuNmDx3cinl5yBD3/4B3QIsIe04b4gSHaePCRZ13B97dKKbPx8vuDBU8lyzoRAqqeCmC6nTTYijHLKpXgSFULSZm9juYWcSngM2DuXK4EoUL4Ku34G3zIf0o+tKMzuriJWYZpX8duN93f5m3i5DbXJRY38d/9XqszoUNHK/k8nABWqngGklCfnJ6OvhONjoOzcFmpI2wvPxb8JvGFU66K/BD+5FnCeDiCXl4wYZSvyLDdbB Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, May 06, 2026 at 09:21:30AM +0800, Ye Liu wrote: >From: Ye Liu > >__khugepaged_enter() sets MMF_VM_HUGEPAGE before allocating the >corresponding mm_slot. If mm_slot_alloc() fails, the function >returns with the flag set but without inserting the mm into the >khugepaged tracking structures. > >This leaves the mm in an inconsistent state: it is marked as >registered (MMF_VM_HUGEPAGE set), but will never be scanned by >khugepaged. Future attempts to register the mm are skipped since >khugepaged_enter_vma() checks the flag and returns early. > >Fix this by clearing MMF_VM_HUGEPAGE when mm_slot_alloc() fails, >restoring the ability to retry registration later. > >Fixes: 16618670276a ("mm: khugepaged: avoid pointless allocation for struct mm_slot") Nit: the title does not exactly match the original commit subject. It should be Fixes: 16618670276a ("mm: khugepaged: avoid pointless allocation for "struct mm_slot"") which includes quotes around "struct mm_slot". No need to resend; I think Andrew can fix it up when applying :) >Signed-off-by: Ye Liu >--- Thanks, LGTM. Reviewed-by: Lance Yang