From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-185.mta0.migadu.com (out-185.mta0.migadu.com [91.218.175.185]) (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 B1EA11779AE for ; Wed, 5 Feb 2025 18:16:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.185 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738779388; cv=none; b=sHAiJW9AxNxQ5tl6c4TST6TUswpf9Ud1gpxE4lGQv2o6eN6T/VUzGxXhkUrB1VHxWGLyeqWUHzdphvRd0igZvR+Ja/XsL/JFJKL8CaTcOFPE13wWSsQ9gljJRz981fpEqp2WNgRyjCOgMd7rJVEIX3JwT3Ef57NeCkhHpso2QvE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738779388; c=relaxed/simple; bh=DS6DbwHGbCZpbzDRkFM4wrbs2iBdv+XhTRDUzdwpWXw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=BXZrMcdxFDKM/GmlLYysX0pgoOBhXbNmBpPKr2OxSRRUTdwS391h9bOKXZ7P1fn6hdbDNEUyG1GgWYjTR/xT9ZOaIE++4RoE2rWn8f1iHjdCRb00+tR2Ehz3G3QLwiGgiCItIYr/Fd9fJN4X546UsleForJ8UKagaJEQZW+FHRE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=EoA+aCHE; arc=none smtp.client-ip=91.218.175.185 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="EoA+aCHE" Date: Wed, 5 Feb 2025 18:16:03 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1738779369; 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: in-reply-to:in-reply-to:references:references; bh=XJK0Vy+lQ3QID6M2iQP3pTvhmW1IQBmtWP8DLFUCWt0=; b=EoA+aCHEdTaupGOpNDxd0hi1UNSHnRR5xeaEc5uGgR6DQfspXVfA6JoIxEsL4fL4WzuG4L AXYUbHFckEwi6yUzdLpXf3kXS9lQ9Zb2GrPT44atPo81oacqpwUAHGVGwauzNKTkYBVhgf Q4TxO7b6Cc2Vad1CKbl40YifntgKIR8= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Yosry Ahmed To: Johannes Weiner Cc: Hamza Mahfooz , linux-mm@kvack.org, Roman Gushchin , Shakeel Butt , Andrew Morton , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Tejun Heo , Michal =?utf-8?Q?Koutn=C3=BD?= , Michal Hocko , Muchun Song , Zach O'Keefe , Kinsey Ho , Yosry Ahmed , Allen Pais Subject: Re: A path forward to cleaning up dying cgroups? Message-ID: References: <20250205180842.GC1183495@cmpxchg.org> Precedence: bulk X-Mailing-List: linux-kernel@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: <20250205180842.GC1183495@cmpxchg.org> X-Migadu-Flow: FLOW_OUT On Wed, Feb 05, 2025 at 01:08:42PM -0500, Johannes Weiner wrote: > On Wed, Feb 05, 2025 at 12:50:19PM -0500, Hamza Mahfooz wrote: > > Cc: Shakeel Butt > > > > On 2/5/25 12:48, Hamza Mahfooz wrote: > > > I was just curious as to what the status of the issue described in [1] > > > is. It appears that the last time someone took a stab at it was in [2]. > > If memory serves, the sticking point was whether pages should indeed > be reparented on cgroup death, or whether they could be moved > arbitrarily to other cgroups that are still using them. > > It's a bit unfortunate, because the reparenting patches were tested > and reviewed, and the arbitrary recharging was just an idea that > ttbomk nobody seriously followed up on afterwards. There was an RFC series [1] for the recharging, but all memcg maintainers hated it :P https://lore.kernel.org/lkml/20230720070825.992023-1-yosryahmed@google.com/ > > We also recently removed the charge moving code from cgroup1, along > with the subtle page access/locking/accounting rules it imposed on the > rest of the MM. I'm doubtful there is much appetite in either camp for > bringing this back. Yeah with the charge moving code gone the case for recharging grows weaker. > > So I would still love to see Muchun's patches merged. They fix a > seemingly universally experienced operational issue in memcg, and we > shouldn't hold it up unless somebody actually posts alternative code. > > Thoughts? Adding Zach and Kinsey who were recently looking into this from the Google side.