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 65A84C6379F for ; Fri, 10 Feb 2023 20:32:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233776AbjBJUcG (ORCPT ); Fri, 10 Feb 2023 15:32:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233552AbjBJUcG (ORCPT ); Fri, 10 Feb 2023 15:32:06 -0500 Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ED6393A09F for ; Fri, 10 Feb 2023 12:32:04 -0800 (PST) Received: by mail-pj1-x1034.google.com with SMTP id a8-20020a17090a6d8800b002336b48f653so5090483pjk.3 for ; Fri, 10 Feb 2023 12:32:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=TNGC2gVkur39N/z2BGm7FqvHrhN7MB6Kvr8/zKYBd54=; b=ggqXtIq5KlvW4+bzHNM7jlAyPY0z+p8Jo7a8W5Rwk3QnaHJBZJYKrMboQklL4ZGFrv doeD+gsAKuhGs6CO8+lmAhnM5DM5DY8zlKWhmcpxPJ18NtE30dQFnad21m2dFAXsZCAc IWwmpfvczOUhuSrW5mcQ/18/WZ9Ewfltyt6cA8gE2QkAtzx5AfbrCOqS0Urw0unKmbqf z2UYJcIBpB1tl7pg9rgtQlmG09i0W8p/w0a+VlN2yHKqCtKNN4uKxuDsYhjky/Drgn64 wdXVTkTZdehl/wP+SsMIOApp8GzW7OugxlIx+sFuTAFkMOuvey8XbdArw4uvJHVbYz/i Lcww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=TNGC2gVkur39N/z2BGm7FqvHrhN7MB6Kvr8/zKYBd54=; b=RrEJXu5TTw1xjP63/jvZr8CspvLakCfdS5uJ5JW97/vqYJJYmdFIgFcyJVnbCD+uXH c01PUdzEHdYR77VEkVSetbVnc1UJoXOH/C8+VMKT28mdOxk710XKiR8xVM2s3YooXf4T GuW3yAIg3V/gdB5eUpl7faH1kTGt+1dIMYeN79eiB3JudaGcnAgFv0lChB3vm4m4uQSl VaosOXDyc5AK+DzhEmPVfDKWp4YLmzmnYKcuP9gSq9gxFlOkDzQhP6YWopQf1zLObE5N nPhgYX8AENn94oNzQOB58MmkKbAreRST7cj4YMBgLFxH4UR4upFjm1BPwctpzcy9dkTO LWEA== X-Gm-Message-State: AO0yUKXfvRORzBvxw3lqCPLvsSm4m8Vrc+aE8DxKjBA1IkHcF8qfYZyW aU2HQKCAz1cYFOj9wI55SoH2Zg== X-Google-Smtp-Source: AK7set/R7DRDye2KopX4VXsYABJedGTdp+oIlslYijdw2jgktzMAsQBFaHyYZ8x0PhoUd6tBAQ0VEQ== X-Received: by 2002:a17:902:d2c3:b0:19a:7217:32af with SMTP id n3-20020a170902d2c300b0019a721732afmr3770005plc.5.1676061124414; Fri, 10 Feb 2023 12:32:04 -0800 (PST) Received: from [192.168.1.136] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id d23-20020a170902b71700b001933b4b1a49sm2701300pls.183.2023.02.10.12.32.03 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 10 Feb 2023 12:32:03 -0800 (PST) Message-ID: <1dd85095-c18c-ed3e-38b7-02f4d13d9bd6@kernel.dk> Date: Fri, 10 Feb 2023 13:32:02 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: copy on write for splice() from file to pipe? Content-Language: en-US To: Linus Torvalds , Andy Lutomirski Cc: Dave Chinner , Matthew Wilcox , Stefan Metzmacher , linux-fsdevel , Linux API Mailing List , io-uring , "linux-kernel@vger.kernel.org" , Al Viro , Samba Technical References: <0cfd9f02-dea7-90e2-e932-c8129b6013c7@samba.org> <20230210021603.GA2825702@dread.disaster.area> <20230210040626.GB2825702@dread.disaster.area> <20230210065747.GD2825702@dread.disaster.area> From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 2/10/23 1:27 PM, Linus Torvalds wrote: > On Fri, Feb 10, 2023 at 11:56 AM Andy Lutomirski wrote: >> >> i think this is almost exactly what Jeremy and Stefan are asking for >> re: notification when the system is done with a zero-copy send: > > Yeah, right now it's all just "incremented page counts", I think. > > Even the pipe code itself doesn't know about writes that have already > been done, but that are pending elsewhere. > > You'd have to ask the target file descriptor itself about "how much do > you have pending" or something. No, we very much do have that for io_uring zerocopy sends, which was in the bit below you snipped from the reply. It'll tell you when data has been sent out, and when the data has been acked. Or what am I missing here? Late to this thread, and there's a ton of stuff go to through. -- Jens Axboe