From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony PERARD Subject: Re: [PATCH 3/3] xen-bus / xen-block: add support for event channel polling Date: Wed, 10 Apr 2019 16:09:18 +0100 Message-ID: <20190410150918.GF1435@perard.uk.xensource.com> References: <20190408151617.13025-1-paul.durrant@citrix.com> <20190408151617.13025-4-paul.durrant@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from us1-rack-dfw2.inumbo.com ([104.130.134.6]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hEErn-00008I-L1 for xen-devel@lists.xenproject.org; Wed, 10 Apr 2019 15:10:23 +0000 Content-Disposition: inline In-Reply-To: <20190408151617.13025-4-paul.durrant@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" To: Paul Durrant Cc: Kevin Wolf , Stefano Stabellini , qemu-block@nongnu.org, qemu-devel@nongnu.org, Max Reitz , Stefan Hajnoczi , xen-devel@lists.xenproject.org List-Id: xen-devel@lists.xenproject.org T24gTW9uLCBBcHIgMDgsIDIwMTkgYXQgMDQ6MTY6MTdQTSArMDEwMCwgUGF1bCBEdXJyYW50IHdy b3RlOgo+IFRoaXMgcGF0Y2ggaW50cm9kdWNlcyBhIHBvbGwgY2FsbGJhY2sgZm9yIGV2ZW50IGNo YW5uZWwgZmQtcyBhbmQgdXNlcwo+IHRoaXMgdG8gaW52b2tlIHRoZSBjaGFubmVsIGNhbGxiYWNr IGZ1bmN0aW9uLgo+IAo+IFRvIHByb3Blcmx5IHN1cHBvcnQgcG9sbGluZywgaXQgaXMgbmVjZXNz YXJ5IGZvciB0aGUgZXZlbnQgY2hhbm5lbCBjYWxsYmFjawo+IGZ1bmN0aW9uIHRvIHJldHVybiBh IGJvb2xlYW4gc2F5aW5nIHdoZXRoZXIgaXQgaGFzIGRvbmUgYW55IHVzZWZ1bCB3b3JrIG9yCj4g bm90LiBUaHVzIHhlbl9ibG9ja19kYXRhcGxhbmVfZXZlbnQoKSBpcyBtb2RpZmllZCB0byBkaXJl Y3RseSBpbnZva2UKPiB4ZW5fYmxvY2tfaGFuZGxlX3JlcXVlc3RzKCkgYW5kIHRoZSBsYXR0ZXIg b25seSByZXR1cm5zIHRydWUgaWYgaXQgYWN0dWFsbHkKPiBwcm9jZXNzZXMgYW55IHJlcXVlc3Rz LiBUaGlzIGFsc28gbWVhbnMgdGhhdCB0aGUgY2FsbCB0byBxZW11X2JoX3NjaGVkdWxlKCkKPiBp cyBtb3ZlZCBpbnRvIHhlbl9ibG9ja19jb21wbGV0ZV9haW8oKSwgd2hpY2ggaXMgbW9yZSBpbnR1 aXRpdmUgc2luY2UgdGhlCj4gb25seSByZWFzb24gZm9yIGRvaW5nIGEgZGVmZXJyZWQgcG9sbCBv ZiB0aGUgc2hhcmVkIHJpbmcgc2hvdWxkIGJlIGJlY2F1c2UKPiB0aGVyZSB3ZXJlIHByZXZpb3Vz bHkgaW5zdWZmaWNpZW50IHJlc291cmNlcyB0byBmdWxseSBjb21wbGV0ZSBhIHByZXZpb3VzCj4g cG9sbC4KPiAKPiBTaWduZWQtb2ZmLWJ5OiBQYXVsIER1cnJhbnQgPHBhdWwuZHVycmFudEBjaXRy aXguY29tPgo+IC0tLQoKUmV2aWV3ZWQtYnk6IEFudGhvbnkgUEVSQVJEIDxhbnRob255LnBlcmFy ZEBjaXRyaXguY29tPgoKVGhhbmtzLAoKLS0gCkFudGhvbnkgUEVSQVJECgpfX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpYZW4tZGV2ZWwgbWFpbGluZyBsaXN0 Clhlbi1kZXZlbEBsaXN0cy54ZW5wcm9qZWN0Lm9yZwpodHRwczovL2xpc3RzLnhlbnByb2plY3Qu b3JnL21haWxtYW4vbGlzdGluZm8veGVuLWRldmVs 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 X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4824C10F11 for ; 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Wed, 10 Apr 2019 15:10:22 +0000 (UTC) X-IronPort-AV: E=Sophos;i="5.60,332,1549929600"; d="scan'208";a="83234990" Date: Wed, 10 Apr 2019 16:09:18 +0100 From: Anthony PERARD To: Paul Durrant Message-ID: <20190410150918.GF1435@perard.uk.xensource.com> References: <20190408151617.13025-1-paul.durrant@citrix.com> <20190408151617.13025-4-paul.durrant@citrix.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190408151617.13025-4-paul.durrant@citrix.com> User-Agent: Mutt/1.11.4 (2019-03-13) Subject: Re: [Xen-devel] [PATCH 3/3] xen-bus / xen-block: add support for event channel polling X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Stefano Stabellini , qemu-block@nongnu.org, qemu-devel@nongnu.org, Max Reitz , Stefan Hajnoczi , xen-devel@lists.xenproject.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: base64 Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Message-ID: <20190410150918.OWt_QaPIVoMvI7zbAE8bNs57JZ_Gt2TfY756HKcBgoA@z> T24gTW9uLCBBcHIgMDgsIDIwMTkgYXQgMDQ6MTY6MTdQTSArMDEwMCwgUGF1bCBEdXJyYW50IHdy b3RlOgo+IFRoaXMgcGF0Y2ggaW50cm9kdWNlcyBhIHBvbGwgY2FsbGJhY2sgZm9yIGV2ZW50IGNo YW5uZWwgZmQtcyBhbmQgdXNlcwo+IHRoaXMgdG8gaW52b2tlIHRoZSBjaGFubmVsIGNhbGxiYWNr IGZ1bmN0aW9uLgo+IAo+IFRvIHByb3Blcmx5IHN1cHBvcnQgcG9sbGluZywgaXQgaXMgbmVjZXNz YXJ5IGZvciB0aGUgZXZlbnQgY2hhbm5lbCBjYWxsYmFjawo+IGZ1bmN0aW9uIHRvIHJldHVybiBh IGJvb2xlYW4gc2F5aW5nIHdoZXRoZXIgaXQgaGFzIGRvbmUgYW55IHVzZWZ1bCB3b3JrIG9yCj4g bm90LiBUaHVzIHhlbl9ibG9ja19kYXRhcGxhbmVfZXZlbnQoKSBpcyBtb2RpZmllZCB0byBkaXJl Y3RseSBpbnZva2UKPiB4ZW5fYmxvY2tfaGFuZGxlX3JlcXVlc3RzKCkgYW5kIHRoZSBsYXR0ZXIg b25seSByZXR1cm5zIHRydWUgaWYgaXQgYWN0dWFsbHkKPiBwcm9jZXNzZXMgYW55IHJlcXVlc3Rz LiBUaGlzIGFsc28gbWVhbnMgdGhhdCB0aGUgY2FsbCB0byBxZW11X2JoX3NjaGVkdWxlKCkKPiBp cyBtb3ZlZCBpbnRvIHhlbl9ibG9ja19jb21wbGV0ZV9haW8oKSwgd2hpY2ggaXMgbW9yZSBpbnR1 aXRpdmUgc2luY2UgdGhlCj4gb25seSByZWFzb24gZm9yIGRvaW5nIGEgZGVmZXJyZWQgcG9sbCBv ZiB0aGUgc2hhcmVkIHJpbmcgc2hvdWxkIGJlIGJlY2F1c2UKPiB0aGVyZSB3ZXJlIHByZXZpb3Vz bHkgaW5zdWZmaWNpZW50IHJlc291cmNlcyB0byBmdWxseSBjb21wbGV0ZSBhIHByZXZpb3VzCj4g cG9sbC4KPiAKPiBTaWduZWQtb2ZmLWJ5OiBQYXVsIER1cnJhbnQgPHBhdWwuZHVycmFudEBjaXRy aXguY29tPgo+IC0tLQoKUmV2aWV3ZWQtYnk6IEFudGhvbnkgUEVSQVJEIDxhbnRob255LnBlcmFy ZEBjaXRyaXguY29tPgoKVGhhbmtzLAoKLS0gCkFudGhvbnkgUEVSQVJECgpfX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpYZW4tZGV2ZWwgbWFpbGluZyBsaXN0 Clhlbi1kZXZlbEBsaXN0cy54ZW5wcm9qZWN0Lm9yZwpodHRwczovL2xpc3RzLnhlbnByb2plY3Qu b3JnL21haWxtYW4vbGlzdGluZm8veGVuLWRldmVs From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:55723) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hEEwB-0002Bn-0d for qemu-devel@nongnu.org; Wed, 10 Apr 2019 11:14:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hEEqw-0001mu-0p for qemu-devel@nongnu.org; Wed, 10 Apr 2019 11:09:31 -0400 Date: Wed, 10 Apr 2019 16:09:18 +0100 From: Anthony PERARD Message-ID: <20190410150918.GF1435@perard.uk.xensource.com> References: <20190408151617.13025-1-paul.durrant@citrix.com> <20190408151617.13025-4-paul.durrant@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20190408151617.13025-4-paul.durrant@citrix.com> Subject: Re: [Qemu-devel] [PATCH 3/3] xen-bus / xen-block: add support for event channel polling List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paul Durrant Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, xen-devel@lists.xenproject.org, Stefan Hajnoczi , Stefano Stabellini , Kevin Wolf , Max Reitz On Mon, Apr 08, 2019 at 04:16:17PM +0100, Paul Durrant wrote: > This patch introduces a poll callback for event channel fd-s and uses > this to invoke the channel callback function. > > To properly support polling, it is necessary for the event channel callback > function to return a boolean saying whether it has done any useful work or > not. Thus xen_block_dataplane_event() is modified to directly invoke > xen_block_handle_requests() and the latter only returns true if it actually > processes any requests. This also means that the call to qemu_bh_schedule() > is moved into xen_block_complete_aio(), which is more intuitive since the > only reason for doing a deferred poll of the shared ring should be because > there were previously insufficient resources to fully complete a previous > poll. > > Signed-off-by: Paul Durrant > --- Reviewed-by: Anthony PERARD Thanks, -- Anthony PERARD 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 X-Spam-Level: X-Spam-Status: No, score=-5.4 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F996C10F11 for ; Wed, 10 Apr 2019 15:17:24 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D2CEB2083E for ; Wed, 10 Apr 2019 15:17:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D2CEB2083E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=citrix.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:33030 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hEEyY-0004ER-Qc for qemu-devel@archiver.kernel.org; Wed, 10 Apr 2019 11:17:22 -0400 Received: from eggs.gnu.org ([209.51.188.92]:55723) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hEEwB-0002Bn-0d for qemu-devel@nongnu.org; Wed, 10 Apr 2019 11:14:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hEEqw-0001mu-0p for qemu-devel@nongnu.org; Wed, 10 Apr 2019 11:09:31 -0400 Received: from smtp03.citrix.com ([162.221.156.55]:61646) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hEEqr-0001Ys-Qn; Wed, 10 Apr 2019 11:09:28 -0400 X-IronPort-AV: E=Sophos;i="5.60,332,1549929600"; d="scan'208";a="83234990" Date: Wed, 10 Apr 2019 16:09:18 +0100 From: Anthony PERARD To: Paul Durrant Message-ID: <20190410150918.GF1435@perard.uk.xensource.com> References: <20190408151617.13025-1-paul.durrant@citrix.com> <20190408151617.13025-4-paul.durrant@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: <20190408151617.13025-4-paul.durrant@citrix.com> User-Agent: Mutt/1.11.4 (2019-03-13) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 162.221.156.55 Subject: Re: [Qemu-devel] [PATCH 3/3] xen-bus / xen-block: add support for event channel polling X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Stefano Stabellini , qemu-block@nongnu.org, qemu-devel@nongnu.org, Max Reitz , Stefan Hajnoczi , xen-devel@lists.xenproject.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190410150918.kIOW9YyeHP4BrrJ0ah440bL4yZk1PH9Diz-9ATghjkk@z> On Mon, Apr 08, 2019 at 04:16:17PM +0100, Paul Durrant wrote: > This patch introduces a poll callback for event channel fd-s and uses > this to invoke the channel callback function. > > To properly support polling, it is necessary for the event channel callback > function to return a boolean saying whether it has done any useful work or > not. Thus xen_block_dataplane_event() is modified to directly invoke > xen_block_handle_requests() and the latter only returns true if it actually > processes any requests. This also means that the call to qemu_bh_schedule() > is moved into xen_block_complete_aio(), which is more intuitive since the > only reason for doing a deferred poll of the shared ring should be because > there were previously insufficient resources to fully complete a previous > poll. > > Signed-off-by: Paul Durrant > --- Reviewed-by: Anthony PERARD Thanks, -- Anthony PERARD