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 F039C42A82; Wed, 12 Mar 2025 13:45:12 +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=1741787115; cv=none; b=oSG14+jwrjW/cgELILXJIlXbWrVwbxLBTjZ0zHAZ+FIEVKF9AZlhACfJJJj/IwwHApnAbejKuCY285GEuUI8nVidslVfd6lrwkLUuhn7f+pTUxQ9j9GxxQFHqaeZVirxgIB6/gddp+uV5fH2amIZrmgWdlsCXThLfNWQYzUAX0E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741787115; c=relaxed/simple; bh=4HAhK6US9YpNBFYaYDKcncY7tvv/cqOdDvxd9JID8Uk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=vDxUuEjw800RYfrm0ngQLa/2vPaRt4uw1MvzNJfyxQ68J1vMpa0PyHAKubg+6wxq1UqYIfVAFWU0WUgjZ65RFcJMhh4FCz2j08UMb8Wt7DVRVB1xHXy2Cy9tMMJFCleOPuTANCTp7B+moZhlKUMbfJMcMxcUmzLqDOQPnE28ugk= 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=nnPbfcl/; 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="nnPbfcl/" 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=mIH+fIUpb4z14XLHnYSwL/PB/xBu/Oavn7NhiKaNRus=; b=nnPbfcl/JjzVTpEx8LURT5nSKQ k4uhb+XrcpQZD3Q3aE3nwvl8B/48TLJGDtzEvuIJW0n2ikKGtbNuu1Pp6erFa8sO42hDXcsaQcPmZ SSMZClF1BgjfoIygwpKflWJfZ3ObOK5gLUDb8kndMdBGD2QnXVbvqf37hQge2omBtE0Pn1uIfjjLP u0Zu6nDy73/7RKXiHwoQJ0hBNCcYrVeuvskDmT2Smwc2qtpEsVWxmbDRU0nOwk8WiA/O6u61W0DeB TJNvcbsU5cVAjTscbk6X9CmtSii24BCOwrvCMhNH+COZzwGVuqzjVxaOMYyNVvcTi0h9FF13dwTnO sum7AIbA==; Received: from hch by bombadil.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tsMOW-00000008by9-0y8J; Wed, 12 Mar 2025 13:45:12 +0000 Date: Wed, 12 Mar 2025 06:45:12 -0700 From: Christoph Hellwig To: John Garry Cc: Christoph Hellwig , brauner@kernel.org, djwong@kernel.org, cem@kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, ojaswin@linux.ibm.com, ritesh.list@gmail.com, martin.petersen@oracle.com Subject: Re: [PATCH v5 09/10] xfs: Allow block allocator to take an alignment hint Message-ID: References: <20250310183946.932054-1-john.g.garry@oracle.com> <20250310183946.932054-10-john.g.garry@oracle.com> <4d9499e3-4698-4d0c-b7bb-104023b29f3a@oracle.com> 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: <4d9499e3-4698-4d0c-b7bb-104023b29f3a@oracle.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Wed, Mar 12, 2025 at 08:05:14AM +0000, John Garry wrote: > > Shouldn't we be doing this by default for any extent size hint > > based allocations? > > I'm not sure. > > I think that currently users just expect extszhint to hint at the > granularity only. > > Maybe users don't require alignment and adding an alignment requirement just > leads to more fragmentation. But does it? Once an extsize hint is set I'd expect that we keep getting more allocation with it. And keeping the aligned is the concept of a buddy allocator which reduces fragmentation. Because of that I wonder why we aren't doing that by default.