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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68DA2C636D6 for ; Thu, 9 Feb 2023 15:07:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230136AbjBIPHu (ORCPT ); Thu, 9 Feb 2023 10:07:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229707AbjBIPHs (ORCPT ); Thu, 9 Feb 2023 10:07:48 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BC5C45ACF4 for ; Thu, 9 Feb 2023 07:07:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1675955231; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=2bykY5ltudiFVwAjrX3Al4RUFY4iK7RUW76wSPYzOKs=; b=e49mOixrr0oy7rOkevC0QOROcabqU4jpUTClnVhJ7LX60oHBUcIeWc7SKmTRM47TQh85Aq X6wcrKoe/RxqkHH1t1Eshmq6XjDvjr1EGBhaejo7oNVmpPdg8QPbD7ogRVZGp1066XA5da AsP2F7vG0T80mZ/FPWNYSvm1DrS/8Nc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-194-sQ-OEzM-NNunWl4RcBiL1A-1; Thu, 09 Feb 2023 10:07:05 -0500 X-MC-Unique: sQ-OEzM-NNunWl4RcBiL1A-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D3429857D07; Thu, 9 Feb 2023 15:07:03 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.24]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6E2F1140EBF6; Thu, 9 Feb 2023 15:07:00 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <20230209102954.528942-1-dhowells@redhat.com> <20230209102954.528942-2-dhowells@redhat.com> To: Matthew Wilcox Cc: dhowells@redhat.com, Jens Axboe , Al Viro , Christoph Hellwig , Jan Kara , Jeff Layton , David Hildenbrand , Jason Gunthorpe , Logan Gunthorpe , Hillf Danton , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzbot+a440341a59e3b7142895@syzkaller.appspotmail.com, Christoph Hellwig , John Hubbard Subject: Re: [PATCH v13 01/12] splice: Fix O_DIRECT file read splice to avoid reversion of ITER_PIPE MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <757357.1675955219.1@warthog.procyon.org.uk> Date: Thu, 09 Feb 2023 15:06:59 +0000 Message-ID: <757358.1675955219@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Matthew Wilcox wrote: > On Thu, Feb 09, 2023 at 10:29:43AM +0000, David Howells wrote: > > + npages = alloc_pages_bulk_list(GFP_USER, npages, &pages); > > Please don't use alloc_pages_bulk_list(). If nobody uses it, it can go > away again soon. Does alloc_pages_bulk_array() work for you? It's > faster. Sure. > > + /* Free any pages that didn't get touched at all. */ > > + for (; reclaim >= PAGE_SIZE; reclaim -= PAGE_SIZE) > > + __free_page(bv[--npages].bv_page); > > If you have that array, you can then use release_pages() to free > them, which will be faster. Um. I would normally overlay the array on end of the bvec[] so that I could save on an allocation (I have to fill in the bvec[] anyway) - which means I wouldn't still have the array at release time. But in this case I can make an exception, though I would've thought that the expectation would be that all the requested data would be fetched. David