From patchwork Wed Jan 9 16:40:17 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Penyaev X-Patchwork-Id: 10754525 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 535CE6C5 for ; Wed, 9 Jan 2019 16:42:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 428612943F for ; Wed, 9 Jan 2019 16:42:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4048B294F5; Wed, 9 Jan 2019 16:42:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AD8F02943F for ; Wed, 9 Jan 2019 16:41:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726811AbfAIQln (ORCPT ); Wed, 9 Jan 2019 11:41:43 -0500 Received: from mx2.suse.de ([195.135.220.15]:57636 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726551AbfAIQkk (ORCPT ); Wed, 9 Jan 2019 11:40:40 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 4A596B012; Wed, 9 Jan 2019 16:40:39 +0000 (UTC) From: Roman Penyaev Cc: Roman Penyaev , Andrew Morton , Davidlohr Bueso , Jason Baron , Al Viro , "Paul E. McKenney" , Linus Torvalds , Andrea Parri , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH 07/15] epoll: extend epitem struct with new members for polling from userspace Date: Wed, 9 Jan 2019 17:40:17 +0100 Message-Id: <20190109164025.24554-8-rpenyaev@suse.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190109164025.24554-1-rpenyaev@suse.de> References: <20190109164025.24554-1-rpenyaev@suse.de> MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP ->bit every epitem has an element inside user item array, this bit is actually an index position of that user item array and also a bit inside ep->items_bm ->ready_events received events in the period when descriptor can't be polled from userspace and ep->rdllist is used for keeping list of ready items ->work work for offloading polling from task context if epfd is polled from userspace but driver does not provide pollflags on wakeup Signed-off-by: Roman Penyaev Cc: Andrew Morton Cc: Davidlohr Bueso Cc: Jason Baron Cc: Al Viro Cc: "Paul E. McKenney" Cc: Linus Torvalds Cc: Andrea Parri Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- fs/eventpoll.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index ae288f62aa4c..637b463587c1 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -9,6 +9,8 @@ * * Davide Libenzi * + * Polling from userspace support by Roman Penyaev + * (C) Copyright 2019 SUSE, All Rights Reserved */ #include @@ -42,6 +44,7 @@ #include #include #include +#include #include /* @@ -176,6 +179,18 @@ struct epitem { /* The structure that describe the interested events and the source fd */ struct epoll_event event; + + /* Bit in user bitmap for user polling */ + unsigned int bit; + + /* + * Collect ready events for the period when descriptor is polled by user + * but events are routed to klists. + */ + __poll_t ready_events; + + /* Work for offloading event callback */ + struct work_struct work; }; #define EPOLL_USER_HEADER_SIZE 128 @@ -2557,12 +2572,6 @@ static int __init eventpoll_init(void) ep_nested_calls_init(&poll_safewake_ncalls); #endif - /* - * We can have many thousands of epitems, so prevent this from - * using an extra cache line on 64-bit (and smaller) CPUs - */ - BUILD_BUG_ON(sizeof(void *) <= 8 && sizeof(struct epitem) > 128); - /* Allocates slab cache used to allocate "struct epitem" items */ epi_cache = kmem_cache_create("eventpoll_epi", sizeof(struct epitem), 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL);