From owner-dev-commits-src-main@freebsd.org Sat Jul 10 00:58:04 2021 Return-Path: Delivered-To: dev-commits-src-main@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 6B0D1649E25; Sat, 10 Jul 2021 00:58:04 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4GMBTm2Czzz4YZd; Sat, 10 Jul 2021 00:58:04 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 3005F1EA3E; Sat, 10 Jul 2021 00:58:04 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 16A0w4VK085355; Sat, 10 Jul 2021 00:58:04 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 16A0w42M085354; Sat, 10 Jul 2021 00:58:04 GMT (envelope-from git) Date: Sat, 10 Jul 2021 00:58:04 GMT Message-Id: <202107100058.16A0w42M085354@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Alexander Motin Subject: git: 63ca9ea4f34d - main - Use sleepq_signal(SLEEPQ_DROP) in cv_signal(). MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: mav X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 63ca9ea4f34d887b66c7b9f1710f5e4be543ebed Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-main@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for the main branch of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 10 Jul 2021 00:58:04 -0000 The branch main has been updated by mav: URL: https://cgit.FreeBSD.org/src/commit/?id=63ca9ea4f34d887b66c7b9f1710f5e4be543ebed commit 63ca9ea4f34d887b66c7b9f1710f5e4be543ebed Author: Alexander Motin AuthorDate: 2021-07-10 00:52:40 +0000 Commit: Alexander Motin CommitDate: 2021-07-10 00:57:58 +0000 Use sleepq_signal(SLEEPQ_DROP) in cv_signal(). Same as wakeup_one()/wakeup_any() commit before it reduces the lock hold time and so contention. MFC after: 1 week --- sys/kern/kern_condvar.c | 27 ++++++++++++--------------- 1 file changed, 12 insertions(+), 15 deletions(-) diff --git a/sys/kern/kern_condvar.c b/sys/kern/kern_condvar.c index e26b689b4e11..ffceee44a5c0 100644 --- a/sys/kern/kern_condvar.c +++ b/sys/kern/kern_condvar.c @@ -397,26 +397,23 @@ _cv_timedwait_sig_sbt(struct cv *cvp, struct lock_object *lock, void cv_signal(struct cv *cvp) { - int wakeup_swapper; if (cvp->cv_waiters == 0) return; - wakeup_swapper = 0; sleepq_lock(cvp); - if (cvp->cv_waiters > 0) { - if (cvp->cv_waiters == CV_WAITERS_BOUND && - sleepq_lookup(cvp) == NULL) { - cvp->cv_waiters = 0; - } else { - if (cvp->cv_waiters < CV_WAITERS_BOUND) - cvp->cv_waiters--; - wakeup_swapper = sleepq_signal(cvp, SLEEPQ_CONDVAR, 0, - 0); - } + if (cvp->cv_waiters == 0) { + sleepq_release(cvp); + return; + } + if (cvp->cv_waiters == CV_WAITERS_BOUND && sleepq_lookup(cvp) == NULL) { + cvp->cv_waiters = 0; + sleepq_release(cvp); + } else { + if (cvp->cv_waiters < CV_WAITERS_BOUND) + cvp->cv_waiters--; + if (sleepq_signal(cvp, SLEEPQ_CONDVAR | SLEEPQ_DROP, 0, 0)) + kick_proc0(); } - sleepq_release(cvp); - if (wakeup_swapper) - kick_proc0(); } /*