From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6CB0C40A944; Mon, 17 Aug 2026 11:38:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786966726; cv=none; b=duuzJ8C51SbSpHjyj/wJgD8AdRkGXRib8Ybpjc9TrcFxjibqbttmAJkSnJ6DHBHgfHqhuaxFdfNevSE/vKNS+6EePGKc+n2xFqIwaMYAWSCKaF9vdNwO35CFYPo/U+SWE8wYqN4wc6qLnBuyMJaHwzgEjEavygq728ZEvyognMs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786966726; c=relaxed/simple; bh=U6BBy2/b5aoKeWQOeV7/KGt+NryFfDAsGjg0Q0NO8D8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=auH/ttTm2GLSE/0Z8DDdnhtdKCpulJOmEHkU8gRe30iQ+aZGf+6M24geAbwjFT/y/DFCSgRshAfKDZ0lBRAS40yCvm1swgAeQFb70kecDuPsjmVnysEQVmKBtfdSjhDvt+fxgTvcYUWhiE4YDO2GZ3f93eg34mHagbmei43RWwk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=amvVG5ic; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="amvVG5ic" 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> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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> 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