From patchwork Tue Sep 13 08:45:20 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 9328551 X-Patchwork-Delegate: snitzer@redhat.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A63FE60839 for ; Tue, 13 Sep 2016 08:48:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 92E4F29227 for ; Tue, 13 Sep 2016 08:48:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 845DF29232; Tue, 13 Sep 2016 08:48:04 +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=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from mx5-phx2.redhat.com (mx5-phx2.redhat.com [209.132.183.37]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 3150729227 for ; Tue, 13 Sep 2016 08:48:03 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by mx5-phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u8D8jUH8020485; Tue, 13 Sep 2016 04:45:32 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id u8D8jTEj004483 for ; Tue, 13 Sep 2016 04:45:29 -0400 Received: from mx1.redhat.com (ext-mx02.extmail.prod.ext.phx2.redhat.com [10.5.110.26]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u8D8jT85004569 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Tue, 13 Sep 2016 04:45:29 -0400 Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A7BF5335F6A; Tue, 13 Sep 2016 08:45:25 +0000 (UTC) Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=twins.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.85_2 #1 (Red Hat Linux)) id 1bjjLG-00004v-JF; Tue, 13 Sep 2016 08:45:22 +0000 Received: by twins.programming.kicks-ass.net (Postfix, from userid 1000) id 4A91B12573B0D; Tue, 13 Sep 2016 10:45:20 +0200 (CEST) Date: Tue, 13 Sep 2016 10:45:20 +0200 From: Peter Zijlstra To: Alasdair Kergon , Mike Snitzer , Thomas Gleixner , Ingo Molnar Message-ID: <20160913084520.GA5012@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.23.1 (2014-03-12) X-Greylist: Sender IP whitelisted by DNSRBL, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Tue, 13 Sep 2016 08:45:28 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Tue, 13 Sep 2016 08:45:28 +0000 (UTC) for IP:'205.233.59.134' DOMAIN:'merlin.infradead.org' HELO:'merlin.infradead.org' FROM:'peterz@infradead.org' RCPT:'' X-RedHat-Spam-Score: -3.793 (BAYES_50, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD) 205.233.59.134 merlin.infradead.org 205.233.59.134 merlin.infradead.org X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-Scanned-By: MIMEDefang 2.78 on 10.5.110.26 X-loop: dm-devel@redhat.com Cc: dm-devel@redhat.com, Mikulas Patocka , linux-kernel@vger.kernel.org Subject: [dm-devel] [RFC][PATCH] dm: Remove dm_bufio_cond_resched() X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Virus-Scanned: ClamAV using ClamSMTP Hi all, While grepping for PREEMPT_VOLUNTARY I ran into dm_bufio_cond_resched() and wondered WTH it was about. Is there anything wrong with the below patch? Acked-by: Thomas Gleixner --- -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index 8625040bae92..125aedc3875f 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -191,19 +191,6 @@ static void dm_bufio_unlock(struct dm_bufio_client *c) mutex_unlock(&c->lock); } -/* - * FIXME Move to sched.h? - */ -#ifdef CONFIG_PREEMPT_VOLUNTARY -# define dm_bufio_cond_resched() \ -do { \ - if (unlikely(need_resched())) \ - _cond_resched(); \ -} while (0) -#else -# define dm_bufio_cond_resched() do { } while (0) -#endif - /*----------------------------------------------------------------*/ /* @@ -741,7 +728,7 @@ static void __flush_write_list(struct list_head *write_list) list_entry(write_list->next, struct dm_buffer, write_list); list_del(&b->write_list); submit_io(b, WRITE, b->block, write_endio); - dm_bufio_cond_resched(); + cond_resched(); } blk_finish_plug(&plug); } @@ -780,7 +767,7 @@ static struct dm_buffer *__get_unclaimed_buffer(struct dm_bufio_client *c) __unlink_buffer(b); return b; } - dm_bufio_cond_resched(); + cond_resched(); } list_for_each_entry_reverse(b, &c->lru[LIST_DIRTY], lru_list) { @@ -791,7 +778,7 @@ static struct dm_buffer *__get_unclaimed_buffer(struct dm_bufio_client *c) __unlink_buffer(b); return b; } - dm_bufio_cond_resched(); + cond_resched(); } return NULL; @@ -923,7 +910,7 @@ static void __write_dirty_buffers_async(struct dm_bufio_client *c, int no_wait, return; __write_dirty_buffer(b, write_list); - dm_bufio_cond_resched(); + cond_resched(); } } @@ -973,7 +960,7 @@ static void __check_watermark(struct dm_bufio_client *c, return; __free_buffer_wake(b); - dm_bufio_cond_resched(); + cond_resched(); } if (c->n_buffers[LIST_DIRTY] > threshold_buffers) @@ -1170,7 +1157,7 @@ void dm_bufio_prefetch(struct dm_bufio_client *c, submit_io(b, READ, b->block, read_endio); dm_bufio_release(b); - dm_bufio_cond_resched(); + cond_resched(); if (!n_blocks) goto flush_plug; @@ -1291,7 +1278,7 @@ int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c) !test_bit(B_WRITING, &b->state)) __relink_lru(b, LIST_CLEAN); - dm_bufio_cond_resched(); + cond_resched(); /* * If we dropped the lock, the list is no longer consistent, @@ -1574,7 +1561,7 @@ static unsigned long __scan(struct dm_bufio_client *c, unsigned long nr_to_scan, freed++; if (!--nr_to_scan || ((count - freed) <= retain_target)) return freed; - dm_bufio_cond_resched(); + cond_resched(); } } return freed; @@ -1808,7 +1795,7 @@ static void __evict_old_buffers(struct dm_bufio_client *c, unsigned long age_hz) if (__try_evict_buffer(b, 0)) count--; - dm_bufio_cond_resched(); + cond_resched(); } dm_bufio_unlock(c);