From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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.lore.kernel.org (Postfix) with ESMTPS id 54E13C77B6E for ; Wed, 12 Apr 2023 15:32:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=jVIUX30CHSeuMRIZ4MbX/VFPgD+9bUpANKvI3RmLVRc=; b=J8vXzXXhjyd+Xd2o6B2jmhlU/B k3Oe4at4VozRng+1amtAj5+3lsAGczURw7lvWxG2xf0obis6mQ5jxhB1zgE6oY8d/Z6ROaXmJN2Zv qNo35jySlhWYRpgaQ3NUq8T1mybKIb7/0C03oWLQZhzF6UO9ppOhj/6v0fd/dWuqTbH+i9riTl65q thLoQpJvRy2H7PWT7+BUISUP76I3DgSZM/Q2pb7BYvypTSKVSzJHyqRUHqvIN9ntH55ozTPYxgJkt UUvkoV6i5J5pF0TYenG5mMy5RBAWwPPoNUEr/GazLG+MY3DcsdcLpQ3ZGPjO2Ey9lcoMl1ocreXys asu8AVEg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pmcSS-003dzs-0C; Wed, 12 Apr 2023 15:32:28 +0000 Received: from hch by bombadil.infradead.org with local (Exim 4.96 #2 (Red Hat Linux)) id 1pmcRi-003dp9-1Q; Wed, 12 Apr 2023 15:31:42 +0000 Date: Wed, 12 Apr 2023 08:31:42 -0700 From: Christoph Hellwig To: David Howells Cc: netdev@vger.kernel.org, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Willem de Bruijn , David Ahern , Matthew Wilcox , Al Viro , Christoph Hellwig , Jens Axboe , Jeff Layton , Christian Brauner , Chuck Lever III , Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Jeroen de Borst , Catherine Sullivan , Shailend Chand , Felix Fietkau , John Crispin , Sean Wang , Mark Lee , Lorenzo Bianconi , Matthias Brugger , AngeloGioacchino Del Regno , Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni , Andrew Morton , linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-nvme@lists.infradead.org Subject: Re: [PATCH net-next v6 04/18] mm: Make the page_frag_cache allocator use per-cpu Message-ID: References: <20230411160902.4134381-1-dhowells@redhat.com> <20230411160902.4134381-5-dhowells@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230411160902.4134381-5-dhowells@redhat.com> X-Mailman-Approved-At: Wed, 12 Apr 2023 08:32:25 -0700 X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Tue, Apr 11, 2023 at 05:08:48PM +0100, David Howells wrote: > Make the page_frag_cache allocator have a separate allocation bucket for > each cpu to avoid racing. This means that no lock is required, other than > preempt disablement, to allocate from it, though if a softirq wants to > access it, then softirq disablement will need to be added. Can you show any performance numbers? > Make the NVMe, mediatek and GVE drivers pass in NULL to page_frag_cache() > and use the default allocation buckets rather than defining their own. Let me ask a third time as I've not got an answer the last two times: why are these callers treated different from the others?