From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-170.mta0.migadu.com (out-170.mta0.migadu.com [91.218.175.170]) (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 597733537EF for ; Tue, 3 Mar 2026 22:47:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.170 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772578071; cv=none; b=Mel5WKqMwayxVKk5GRKvfT+8mE/j+LvuY1Tw+FqcxB+wfrRD5CM5aTYweEutNPS6Cdw3xCr5O8AqS3l3xtMuHp8JhgHY9bqUfKrQxnAfStGZBgiEgNy65FeQyymDFns7sO1TPbuf/PioIy1G8EGxxtHFXcWoGjSbm7AkIrvM2ts= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772578071; c=relaxed/simple; bh=ICZIz7yhJOHKhJyTBDJc1zOquwlbCKbIXlhXr1pWiVQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JRNhigeKuHCjpAOpYkOijIAswla0DX1w3eUzDouF2zUq7oFGqaAzTCe0tVNlqf6WOHueZky3a64m3Qow9jyNkKjW+iL+8Pehyfvj6lffJnkRMr5wdTkjDDuh6ZhIgYQrkLaBKx3DBwpDtaQop55qmOyNeXbVsA0qSDuZpjt71kM= 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=EVq7jMda; arc=none smtp.client-ip=91.218.175.170 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="EVq7jMda" Date: Tue, 3 Mar 2026 14:47:41 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1772578066; 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=EKkcFIW0rZcSJrQSa7i3+w3BkUEejorX4Hk2Yq5/aOg=; b=EVq7jMdaPB3N4r5uSZRYVIPkomqpvsSxY2BUZ6LiuO2tjTYzIX7DuN/l9d/d9LTKNzPfw+ AKH+o5wincI51CR5s72Vn5GloyOkWyItpVWsQuSU7ctXGKmMF8Tk4JTIG5zqAaTg4aXaW4 2NuYaMixy112qoj2uMHs9azQ618/pLI= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Shakeel Butt To: Matt Fleming Cc: Andrew Morton , Jens Axboe , Minchan Kim , Sergey Senozhatsky , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-team@cloudflare.com, Matt Fleming , roman.gushchin@linux.dev Subject: Re: [RFC PATCH 0/1] mm: Reduce direct reclaim stalls with RAM-backed swap Message-ID: References: <20260303115358.1323188-1-matt@readmodwrite.com> 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: X-Migadu-Flow: FLOW_OUT On Tue, Mar 03, 2026 at 07:37:54PM +0000, Matt Fleming wrote: > On Tue, Mar 03, 2026 at 06:59:04AM -0800, Shakeel Butt wrote: > > Hi Matt, > > > > Thanks for the report and one request I have is to avoid cover letter for a > > single patch to avoid partitioning the discussion. > > Noted. > > > Have you tried zswap and if you see similar issues with zswap? > > Yes, we've started experimenting with zswap but that's still in > progress. > > > Over the time we (kernel MM community) have implicitly decided to keep the > > kernel oom-killer very conservative as adding more heuristics in the reclaim/oom > > path makes the kernel more unreliable and punt the aggressiveness of oom-killing > > to the userspace as a policy. All major Linux deployments have started using > > userspace oom-killers like systemd-oomd, Android's LMKD, fb-oomd or some > > internal alternatives. That provides more flexibility to define the > > aggressiveness of oom-killing based on your business needs. > > > > Though userspace oom-killers are prone to reliability issues (oom-killer getting > > stuck in reclaim or not getting enough CPU), so we (Roman) are working on adding > > support for BPF based oom-killer where wen think we can do oom policies more > > reliably. > > > > Anyways, I am wondering if you have tried systemd-oomd or some userspace > > alternative. If you are interested in BPF oom-killer, we can help with that as > > well. > > oomd is also being discussed but so far we haven't experimented with it > yet. > > What's the status of BPF oom-killer: is this the latest? > > https://lore.kernel.org/all/20260127024421.494929-1-roman.gushchin@linux.dev/ Yes this is the latest and I think Roman is planning to send the next version soon.