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=-2.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED,USER_AGENT_GIT 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 0C932C6778F for ; Thu, 26 Jul 2018 08:29:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B21AC2064D for ; Thu, 26 Jul 2018 08:29:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="nBCftmjs" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B21AC2064D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729320AbeGZJpQ (ORCPT ); Thu, 26 Jul 2018 05:45:16 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:45364 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728600AbeGZJpP (ORCPT ); Thu, 26 Jul 2018 05:45:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=HXy3zv26q8SH0hFyF5lTNkg3u2wWghn9TvenKr+09hM=; b=nBCftmjsZya3DMI/VUXGmM1LO 9JWURRK/5rukucSefomhXqxRNi4Use/8ZDZ0EnTmlp6gM2i1AF6bjD3q9KfkVhR4pvqrrnKZH2KJB /3SmSH8QY4L4Yoamk8yHY/mCfAAwd2dpwxxncGlPougMG5HleD8s2ze+do2o1M320jLXW2+H64Cgf 2i42SiZuOniQDbPl5K/JKmxj+djapHnZwlcfHx4wfnVcddhuhxfk5J71px/IO2ieZNQGLYX9VK3sE j2i7+xix9FX8pd7gPh9Ryw+YF/ZayozWPURTlYvPgd0uTdQro4oCPCEWMYrIwPtul4CWXfcpRhlUC XjGHpS3lg==; Received: from 089144199017.atnat0008.highway.a1.net ([89.144.199.17] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fibeK-00080R-T2; Thu, 26 Jul 2018 08:29:30 +0000 From: Christoph Hellwig To: viro@zeniv.linux.org.uk Cc: Avi Kivity , linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 4/4] aio: allow direct aio poll comletions for keyed wakeups Date: Thu, 26 Jul 2018 10:29:03 +0200 Message-Id: <20180726082903.30273-5-hch@lst.de> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180726082903.30273-1-hch@lst.de> References: <20180726082903.30273-1-hch@lst.de> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If we get a keyed wakeup for a aio poll waitqueue and wake can acquire the ctx_lock without spinning we can just complete the iocb straight from the wakeup callback to avoid a context switch. Signed-off-by: Christoph Hellwig --- fs/aio.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index cf364d75abe9..ea744092387d 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1673,11 +1673,25 @@ static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, void *key) { struct poll_iocb *req = container_of(wait, struct poll_iocb, wait); + struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll); __poll_t mask = key_to_poll(key); /* for instances that support it check for an event match first: */ - if (mask && !(mask & req->events)) - return 0; + if (mask) { + if (!(mask & req->events)) + return 0; + + /* try to complete the iocb inline if we can: */ + if (spin_trylock(&iocb->ki_ctx->ctx_lock)) { + req->done = true; + list_del(&iocb->ki_list); + spin_unlock(&iocb->ki_ctx->ctx_lock); + + list_del_init(&req->wait.entry); + aio_poll_complete(iocb, mask); + return 1; + } + } list_del_init(&req->wait.entry); schedule_work(&req->work); -- 2.18.0