From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 264A937FF7A for ; Fri, 10 Apr 2026 11:08:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775819301; cv=none; b=bNJnO2RTld7xrUo/mSiapXO7k9VD9Tho3ZbhyzMwEbEwoJ+DKzKSQUs1UhEQCQfNM1OLkADqY9rMHuAceBx/HXDLcOOmFFQVnlh+I1bYW1dReLlWNI8otq8igvAt9kEmPW548D8/yRsDzGqJtM8rhFg8i50dyHz3qJDVqHpWsw0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775819301; c=relaxed/simple; bh=Xfolxi+7/hMRQt796KFXCq5D6rc+fb5WDqG6Z/g/CCY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sAAl95uBynadi2PrtGBrwOCxkVWE7tCDvXj3dxE6yCQ5FqCek0SkIjqCUrvkoYZDYQGAWdxuWB3Tre7nYckHPn4kRBWW6MhuVNCdhVozG1l3IlIWzpoE9BT4q6YxPipEmg6EkBmCQC0zl+YTUL27gDvPVX/AABDooGt+fQsV/1I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=knWOB3VA; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="knWOB3VA" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Xk3li1I24xXhjUCjfH0QaipKwS9GLoq65H2d0oESdI8=; b=knWOB3VAByYCcpkF0lENzRH+ip aVuP52BPDwBNuQU1+PdpEGH/ldK009CzPSvk4lJ56usBnn6Q0VM5vASn5ZD1XcsRCaViYFS0c8/Ha qbattmUm28AM+8E6/CqlHMZls9hRiZpCMyhvEpQKWvzSsZW3nF17zVYMn5oHrziyAzKbfmju37qZO O8MYZTwLVdLCIApCjzDAJ/eLj6Ri3D/BPckKbCuMQQ9GZPRDax9xQbAEDYRbQCeG0wBZ8v/vXFbhn Y/03kH+Ez0v5Ms4FAYkAhUGmZmCBNnR0nl4MUutiOf9IOAQHUK5cypEjM0/PGmxDRSovwOFFhhC+7 ko9qzmoA==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1wB9ig-0000000C3jL-3MIo; Fri, 10 Apr 2026 11:08:14 +0000 Date: Fri, 10 Apr 2026 04:08:14 -0700 From: Christoph Hellwig To: Boris Burkov Cc: Amir Goldstein , Jan Kara , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Matthew Wilcox , lsf-pc@lists.linux-foundation.org Subject: Re: [Lsf-pc] [LSF/MM/BPF TOPIC] Filesystem inode reclaim Message-ID: References: <20260409164834.GA3472346@zen.localdomain> Precedence: bulk X-Mailing-List: linux-fsdevel@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: <20260409164834.GA3472346@zen.localdomain> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Thu, Apr 09, 2026 at 09:48:34AM -0700, Boris Burkov wrote: > > > This way, kswapd / direct reclaim doesn't wait for hard to reclaim inodes > > > and they can work on freeing memory needed for freeing of hard to reclaim > > > inodes. So warnings about GFP_NOFAIL allocations aren't only papered over, > > > they should really be addressed. > > One question that pops in my mind (which is similar to an issue you and > Qu debugged with the btrfs metadata reclaim floor earlier this year) is: > what if the hard to reclaim inodes are the *only* source of significant > reclaimable space? (disk)space or memory? If this about disk space, make sure your file system ENOSPC handling triggers inode reclaim, XFS already does it. If it is the only source of memory we just need to do the slow reclaim to gain memory. You better use mempools or similar to make it safe.