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 D800B3C488 for ; Tue, 19 Mar 2024 21:41:28 +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=1710884490; cv=none; b=tH/IF6inO2XrVP23VCypyIyKZOOl4M1zJ8vtDywxINTJaq6etuUP8qJOGgPLd3O3Fchvpp+egHiPVeT9Gbjnqo8URnKC2VAlteq4K7G6WO83MLJIdEy2hlzpDM9eER7oJktOrwk7fWfiZIv5NiA1woT1uNX1+bIgyygNJcdOGok= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710884490; c=relaxed/simple; bh=wlphI7GsSP85r6eukHNngGbYkNwl/CYGWT8mndfMIfI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Z5btbcRZgWMze+E1KpgveT3bSkvIaN/4etL5B8mpTHaCYrwiv7qdJ1VOD9RFANA6Qd+KX34ZXuK3t7NPPtsDA9Mo69TQuxM0T2MZwcZaqlRamwCm5tthX0ZjVm3LG+01YYE2qpk5fFtq/qR8JzbJy4u5UVxSKpRBJE9OV3ZJZeY= 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=F93pOJWP; 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="F93pOJWP" 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=ZbN4MgAdyMNCMj0Ulu7EKUER1uJdBGLbfEGlvnguEOc=; b=F93pOJWPMm2YlhJj1TgpVS20Ow sDpFG/0K2P/HYLXJ9NWPohOD7MVRD5yad2I1la4/tlIBuCYGuGYz1hwWRQUd0yUvOztt6Z1eKIICK srDiEb1MELs8cViYR/oP3I5HnSH/pH1GOtXV6vpLfrjukdl8Yp4zsokgq5LnZe0Xs53pc7q/jZJx0 AJwC4PWAPsnE6OUh+WBFhpQcJ5HWE1c5GEAUqjoNc05j3ivtmISYnOHHK40RfsAI8dqAMjh4EUmVw 6tIf+XL4X8JZps/tCrYD7SAl0ijm6mYZVN8Ud27JtR/OJwv0mWJ8STroQqvVLneWHpa0yGx54FIjN YYtjxhhg==; Received: from hch by bombadil.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1rmhD5-0000000EKP4-2bpM; Tue, 19 Mar 2024 21:41:27 +0000 Date: Tue, 19 Mar 2024 14:41:27 -0700 From: Christoph Hellwig To: "Darrick J. Wong" Cc: Christoph Hellwig , Dave Chinner , linux-xfs@vger.kernel.org Subject: Re: [PATCH 3/9] xfs: convert buffer cache to use high order folios Message-ID: References: <20240318224715.3367463-1-david@fromorbit.com> <20240318224715.3367463-4-david@fromorbit.com> <20240319172909.GP1927156@frogsfrogsfrogs> <20240319213827.GQ1927156@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: <20240319213827.GQ1927156@frogsfrogsfrogs> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Tue, Mar 19, 2024 at 02:38:27PM -0700, Darrick J. Wong wrote: > 64k is the maximum xattr value size, yes. But remote xattr value blocks > now have block headers complete with owner/uuid/magic/etc. Each block > can only store $blksz-56 bytes now. Hence that 64k value needs > ceil(65536 / 4040) == 17 blocks on a 4k fsb filesystem. Uggg, ok. I thought we'd just treat remote xattrs as data and don't add headers. That almost asks for using vmalloc if the size is just above a a power of two. > Same reason. Merkle tree blocks are $blksz by default, but storing a > 4096 blob in the xattrs requires ceil(4096 / 4040) == 2 blocks. Most of > that second block is wasted. *sad panda face*. We should be able to come up with something better than that..