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 456981C0DE5 for ; Sat, 30 Mar 2024 05:38:47 +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=1711777130; cv=none; b=ER3OHtpTw9R6/iB8olCjwWhiwSdAPBy7epcjY9ursXsKHwtxuPFCPodu2Sr2kWahwaK14GvdaHkphs9BehEQI0vkBPePzMQBA5pbvRh0Ty5I8AQYbWr5JCAZEQsVbMrUwFwdwIOrutgJ9rba5OV+owR54v1nrCJS5HlmLD87RWo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711777130; c=relaxed/simple; bh=jgAaLEciajX915p5vo1p69cBk+sueUuFUExXzpHpJzU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=n8H6Gp+g36cwet3az5nH2q7VoXm3RkWazh7kaJM41PjVpKVbecZPVO7R+EVBfIJa7xn/STvIvtpVZqEOpct4GiGTYbdBWjI7gtHjlwkpfUi+dqL0PdNpgKyvRgNigmLOlHnD+LrEI2RyHSNbnj/UvEFXQdIkhQEYQTxdk4aHzGw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (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=yojFm5Il; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (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="yojFm5Il" 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=yAy7GIIY7PyxgTjUD9V946dMxKuo1QHMQWNZEsrMOmE=; b=yojFm5IlmNvJJ0XooW/NpdyPiX E1Opix4V44PPzJzMYJXZz7iUE/T92SgNLdbCFwYO4JH7JfaEEWkIgFFB82F0Sr2GH2junnnCfb4sP t3G4CuKQjfeZrCF7JPPawJ1MZltxd7g7CJRsHhXbx/mij0DUznnYvCOtszHPV5EPjQgOXEvULxZgY 2CWVHFG6NVLT31XbwRwsoMcOcmnzsNxERhveZdJvPuF+s/SbDWxiK2qvRkn5Fgw7/38WfdtWihwzL JOeosteMy6VHQtrTM+xisfpPWyLJeVaHa7F3+5y4ixdgicOy0IZJePscxANPZXWtyhTatIaHNlXYz 4RQOSWyw==; Received: from hch by bombadil.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1rqRQV-00000002qiz-0GUH; Sat, 30 Mar 2024 05:38:47 +0000 Date: Fri, 29 Mar 2024 22:38:47 -0700 From: Christoph Hellwig To: "Darrick J. Wong" Cc: Christoph Hellwig , linux-xfs@vger.kernel.org Subject: Re: [PATCH 1/1] xfs: fix severe performance problems when fstrimming a subset of an AG Message-ID: References: <171150385517.3220448.15319110826705438395.stgit@frogsfrogsfrogs> <171150385535.3220448.4852463781154330350.stgit@frogsfrogsfrogs> <20240329213520.GQ6390@frogsfrogsfrogs> Precedence: bulk X-Mailing-List: linux-xfs@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: <20240329213520.GQ6390@frogsfrogsfrogs> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Fri, Mar 29, 2024 at 02:35:20PM -0700, Darrick J. Wong wrote: > Welll... you could argue that if the underlying "thin provisioning" is > actually just an xfs file, that punching tons of tiny holes in that file > could increase the height of the bmbt. In that case, you'd want to > reduce the chances of the punch failing with ENOSPC by punching out > larger ranges to free up more blocks. That is a somewhat reaonable line of thougt. But is an underprovisioned device near ENOSPC really the target here vs an SSD? Either way, if we have good reasons for by-cnt except for it being a little simpler I can live with keeping it. In doubt I just prefer to have simple code and one implementation instead of two.