From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 350361BDE4; Wed, 29 Nov 2023 20:00:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eAPr/pDM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 82DC2C433CA; Wed, 29 Nov 2023 20:00:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701288035; bh=qWUQirFKWRiblfw3zPB4C99l56UyCJAjh7X5MpvzrTU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eAPr/pDMHuMHVgLcvpVTs3xRM2yiYGvuvaNrTm17Ed+WYZ6q48wSpdA//iHgvkT0i NEpX508bf6XsHKg57lJfI3nHE/eYGknPzb/MZeUiMwepXVZFeToG+HZMAaE4zPKyRi dtwO94COZ2rZiP1fRVWV/x7HXNzHIAvP4FSS/SABoUfTW+3oXE2Up9DEea0iNlCCd2 sLPi7mSspQ7V1CPKmNnrFKzbNFnzpFuDFcKk3zI7IxDwDTyl3GHwAJmxrHsrNJsyJU MrO8ktQhiEAZlxE75tPbpEoftF88DhnFYsLmjLBfq/9zJma7EM9bBsgC3fMYWmyCLR J1dyAoz1kER1w== Date: Wed, 29 Nov 2023 15:00:34 -0500 From: Sasha Levin To: Mikulas Patocka Cc: Christian Loehle , stable-commits@vger.kernel.org, stable@vger.kernel.org, Alasdair Kergon , Mike Snitzer , dm-devel@lists.linux.dev Subject: Re: Patch "dm delay: for short delays, use kthread instead of timers and wq" has been added to the 6.6-stable tree Message-ID: References: <20231129025441.892320-1-sashal@kernel.org> <30e67bef-4aaf-31d6-483f-2ca6523099c3@redhat.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: On Wed, Nov 29, 2023 at 08:02:23PM +0100, Mikulas Patocka wrote: > > >On Wed, 29 Nov 2023, Sasha Levin wrote: > >> On Wed, Nov 29, 2023 at 07:16:52PM +0100, Mikulas Patocka wrote: >> > >> > >> >On Wed, 29 Nov 2023, Sasha Levin wrote: >> > >> >> On Wed, Nov 29, 2023 at 06:28:16PM +0100, Mikulas Patocka wrote: >> >> > >> >> > >> >> >On Wed, 29 Nov 2023, Christian Loehle wrote: >> >> > >> >> >> Hi Mikulas, >> >> >> Agreed and thanks for fixing. >> >> >> Has this been selected for stable because of: >> >> >> 6fc45b6ed921 ("dm-delay: fix a race between delay_presuspend and >> >> >> delay_bio") >> >> >> If so, I would volunteer do the backports for that for you at least. >> >> > >> >> >I wouldn't backport this patch - it is an enhancement, not a bugfix, so it >> >> >doesn't qualify for the stable kernel backports. >> >> >> >> Right - this watch was selected as a dependency for 6fc45b6ed921 >> >> ("dm-delay: fix a race between delay_presuspend and delay_bio"). >> >> >> >> In general, unless it's impractical, we'd rather take a dependency chain >> >> rather than deal with a non-trivial backport as those tend to have >> >> issues longer term. >> >> >> >> -- >> >> Thanks, >> >> Sasha >> > >> >The patch 70bbeb29fab0 ("dm delay: for short delays, use kthread instead >> >of timers and wq") changes behavior of dm-delay from using timers to >> >polling, so it may cause problems to people running legacy kernels - the >> >polling consumes more CPU time than the timers - so I think it shouldn't >> >go to the stable kernels where users expect that there will be no >> >functional change. >> > >> >Here I'm submitting the patch 6fc45b6ed921 backported for 6.6.3. >> >> Is this okay for 6.1 too? > >Yes, it is. It applies to kernels as old as 4.19. Great, applied all the way back to 4.19. Thanks! -- Thanks, Sasha