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 E3656C5DF66 for ; Mon, 17 Aug 2026 11:38:48 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E51F86B0165; Mon, 17 Aug 2026 07:38:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E29ED6B0169; Mon, 17 Aug 2026 07:38:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D3F6C6B016B; Mon, 17 Aug 2026 07:38:47 -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 AC6836B0165 for ; Mon, 17 Aug 2026 07:38:47 -0400 (EDT) Received: from smtpin13.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 36DFAA076A for ; Mon, 17 Aug 2026 11:38:47 +0000 (UTC) X-FDA: 85110564294.13.F46F70C Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf28.hostedemail.com (Postfix) with ESMTP id AF0D9C0004 for ; Mon, 17 Aug 2026 11:38:45 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=amvVG5ic; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf28.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1786966725; 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=Kz5p/H0TIZKomsHJng/nr5w+ftLpRUyUqVulCAYcvP8=; b=cmv60isZ1aTrjoZBDPMNNxmphaB4rK9LoCRMI9hrN3KCkFKBy9Zgydwke9XVDpfGB+gzWW eY0SqpTH/5AEWcsS/7taamPbU370q1VAefP1YnqzR3HgQFR9BEUpRqWor1X45YsiIpMm7N SKWAqDt26rcgOXGRqXc1jy+diezvKd0= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=amvVG5ic; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf28.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1786966725; b=agJgm08CdE5ptzUVeAVMbD5FWwFIZUtX4RfiiESvFKVV00G83syW6yOJ++qfG246PZKN1y ptBfSf3lT/djSreEUnu+/MHCjy04qfZWeyPnlOXGdD/tTiKNMi6HdVOJj6QqF2SVOCKRI1 tPI/rqLb8Xn/N9btd2ogJbN/DKqqRPo= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 5221D60204; Mon, 17 Aug 2026 11:38:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5F3A01F00A3A; Mon, 17 Aug 2026 11:38:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786966725; bh=Kz5p/H0TIZKomsHJng/nr5w+ftLpRUyUqVulCAYcvP8=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=amvVG5icoRLGLTkN+kl08tXSEf0mSAQIWZx5Cm6O/l274LtGPX2bSEA+FNnog0COq 85aHOeYtR2MhelU0R3OlN1lJkvEZohbaVkUwTchFvrkqTwaR1sQQtXIkfoBQtdgKOO LPP2wu7WyuUNOM7ZEcOZS6Vnfl6qmAu/aBIcHwb3HyRXR22N9ihRrMkm9B7H9hq/1v HOUVxTSFbLNBLClRy5kIRFZUMWVA8004T5pkZM/bWFfzbCExMvCdTvs2qiWcg3GTxM afb7lWV54TiyPsCApKQyB01yxNgzjJzlBaKU8w5KRcvMJcd+mNuvOb+7KgnLWDzIiC syq+PN1giBaOQ== Date: Mon, 17 Aug 2026 12:38:25 +0100 From: "Lorenzo Stoakes (ARM)" To: "Nico Pache (Red Hat)" Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Andrew Morton , David Hildenbrand , Zi Yan , Baolin Wang , "Liam R. Howlett" , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Shuah Khan Subject: Re: [PATCH v4 6/7] mm/khugepaged: unmap pte before releasing vma write lock Message-ID: References: <20260811-khugepaged_pte_refactor-v4-0-ddac39d61c4a@linux.dev> <20260811-khugepaged_pte_refactor-v4-6-ddac39d61c4a@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260811-khugepaged_pte_refactor-v4-6-ddac39d61c4a@linux.dev> X-Rspam-User: X-Rspamd-Queue-Id: AF0D9C0004 X-Rspamd-Server: rspam07 X-Stat-Signature: 6zxhxj7186xwrzk7emg7u1wnoia3djzd X-HE-Tag: 1786966725-122186 X-HE-Meta: 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 3yjRbCc9 4T1RXdftjWDetqqtgo75HaEaU8fWlJ2DmPPuLkkay11ZN3DvILoJISFgM0aQjCS4omr7cazF7MuGDKbt3ol2cv7ZahZw0Svj4lNjuQHOJuqm7FqOy5zDaXbT175v0VM4/B8D9KdUcZuHt4iURBuR5HXD2EAVXOFAWR6+2Wv24pgVXIAd1NmBefiw9GOLBd6Y/C2QM9GIIaL448dx9LeMDsZ/g+d4255SIoNOWal0wV/i0p6DcgrjCS9ojB5wA5dGXAOFgcTY0Q1aBpqeNRzqD2QQKQA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Aug 11, 2026 at 06:48:38AM -0600, Nico Pache (Red Hat) wrote: > We are currently dropping the anon_vma write lock before unmapping the > PTE. Although this is safe, due to us still holding the mmap_write_lock, > its safer and less confusing to switch the order of these two operations. > > Suggested-by: David Hildenbrand > Acked-by: David Hildenbrand (Arm) > Signed-off-by: Nico Pache (Red Hat) LGTM so: Reviewed-by: Lorenzo Stoakes (ARM) > --- > mm/khugepaged.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index b7372aba4417..0ba637df9c48 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -1546,10 +1546,10 @@ static enum scan_result collapse_huge_page(struct mm_struct *mm, unsigned long s > > result = SCAN_SUCCEED; > out_up_write: > - if (anon_vma_locked) > - anon_vma_unlock_write(vma->anon_vma); > if (pte) > pte_unmap(pte); > + if (anon_vma_locked) > + anon_vma_unlock_write(vma->anon_vma); > mmap_write_unlock(mm); > out_nolock: > if (folio) > > -- > 2.55.0 > -- Cheers, Lorenzo