From owner-svn-src-all@freebsd.org Mon Mar 5 00:30:08 2018 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id E290CF428AE; Mon, 5 Mar 2018 00:30:07 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 94F0E78C97; Mon, 5 Mar 2018 00:30:07 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 8BB761C9AA; Mon, 5 Mar 2018 00:30:07 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id w250U7SS076204; Mon, 5 Mar 2018 00:30:07 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id w250U7gm076203; Mon, 5 Mar 2018 00:30:07 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <201803050030.w250U7gm076203@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Mon, 5 Mar 2018 00:30:07 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r330432 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: mjg X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 330432 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 05 Mar 2018 00:30:08 -0000 Author: mjg Date: Mon Mar 5 00:30:07 2018 New Revision: 330432 URL: https://svnweb.freebsd.org/changeset/base/330432 Log: lockmgr: save on sleepq when cmpset fails Modified: head/sys/kern/kern_lock.c Modified: head/sys/kern/kern_lock.c ============================================================================== --- head/sys/kern/kern_lock.c Mon Mar 5 00:15:56 2018 (r330431) +++ head/sys/kern/kern_lock.c Mon Mar 5 00:30:07 2018 (r330432) @@ -296,7 +296,7 @@ sleeplk(struct lock *lk, u_int flags, struct lock_obje static __inline int wakeupshlk(struct lock *lk, const char *file, int line) { - uintptr_t v, x; + uintptr_t v, x, orig_x; u_int realexslp; int queue, wakeup_swapper; @@ -311,7 +311,9 @@ wakeupshlk(struct lock *lk, const char *file, int line * path in order to handle wakeups correctly. */ sleepq_lock(&lk->lock_object); - x = lk->lk_lock & (LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS); + orig_x = lk->lk_lock; +retry_sleepq: + x = orig_x & (LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS); v = LK_UNLOCKED; /* @@ -360,11 +362,16 @@ wakeupshlk(struct lock *lk, const char *file, int line queue = SQ_SHARED_QUEUE; } - if (!atomic_cmpset_rel_ptr(&lk->lk_lock, LK_SHARERS_LOCK(1) | x, - v)) { + if (lockmgr_sunlock_try(lk, &orig_x)) { sleepq_release(&lk->lock_object); - continue; + break; } + + x |= LK_SHARERS_LOCK(1); + if (!atomic_fcmpset_rel_ptr(&lk->lk_lock, &x, v)) { + orig_x = x; + goto retry_sleepq; + } LOCK_LOG3(lk, "%s: %p waking up threads on the %s queue", __func__, lk, queue == SQ_SHARED_QUEUE ? "shared" : "exclusive"); @@ -602,6 +609,7 @@ lockmgr_slock_hard(struct lock *lk, u_int flags, struc */ sleepq_lock(&lk->lock_object); x = lk->lk_lock; +retry_sleepq: /* * if the lock can be acquired in shared mode, try @@ -617,10 +625,9 @@ lockmgr_slock_hard(struct lock *lk, u_int flags, struc * loop back and retry. */ if ((x & LK_SHARED_WAITERS) == 0) { - if (!atomic_cmpset_acq_ptr(&lk->lk_lock, x, + if (!atomic_fcmpset_acq_ptr(&lk->lk_lock, &x, x | LK_SHARED_WAITERS)) { - sleepq_release(&lk->lock_object); - continue; + goto retry_sleepq; } LOCK_LOG2(lk, "%s: %p set shared waiters flag", __func__, lk); @@ -755,6 +762,7 @@ lockmgr_xlock_hard(struct lock *lk, u_int flags, struc */ sleepq_lock(&lk->lock_object); x = lk->lk_lock; +retry_sleepq: /* * if the lock has been released while we spun on @@ -777,7 +785,7 @@ lockmgr_xlock_hard(struct lock *lk, u_int flags, struc v = x & (LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS); if ((x & ~v) == LK_UNLOCKED) { v &= ~LK_EXCLUSIVE_SPINNERS; - if (atomic_cmpset_acq_ptr(&lk->lk_lock, x, + if (atomic_fcmpset_acq_ptr(&lk->lk_lock, &x, tid | v)) { sleepq_release(&lk->lock_object); LOCK_LOG2(lk, @@ -785,8 +793,7 @@ lockmgr_xlock_hard(struct lock *lk, u_int flags, struc __func__, lk); break; } - sleepq_release(&lk->lock_object); - continue; + goto retry_sleepq; } /* @@ -794,10 +801,9 @@ lockmgr_xlock_hard(struct lock *lk, u_int flags, struc * fail, loop back and retry. */ if ((x & LK_EXCLUSIVE_WAITERS) == 0) { - if (!atomic_cmpset_ptr(&lk->lk_lock, x, + if (!atomic_fcmpset_ptr(&lk->lk_lock, &x, x | LK_EXCLUSIVE_WAITERS)) { - sleepq_release(&lk->lock_object); - continue; + goto retry_sleepq; } LOCK_LOG2(lk, "%s: %p set excl waiters flag", __func__, lk);