From owner-svn-src-all@freebsd.org Mon Dec 16 00:04:34 2019 Return-Path: Delivered-To: svn-src-all@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 42E231D3057; Mon, 16 Dec 2019 00:04:34 +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 TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 47bhN2121fz46wV; Mon, 16 Dec 2019 00:04:34 +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 1E9631CEF9; Mon, 16 Dec 2019 00:04:34 +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 xBG04YfA031516; Mon, 16 Dec 2019 00:04:34 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id xBG04XJW031515; Mon, 16 Dec 2019 00:04:33 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <201912160004.xBG04XJW031515@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Mon, 16 Dec 2019 00:04:33 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r355789 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: mjg X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 355789 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: 2.1.29 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, 16 Dec 2019 00:04:34 -0000 Author: mjg Date: Mon Dec 16 00:04:33 2019 New Revision: 355789 URL: https://svnweb.freebsd.org/changeset/base/355789 Log: mtx: eliminate recursion support from thread lock Now that it is not used after schedlock changes got merged. Note the unlock routine temporarily still checks for it on account of just using regular spin unlock. This is a prelude towards a general clean up. Modified: head/sys/kern/kern_mutex.c Modified: head/sys/kern/kern_mutex.c ============================================================================== --- head/sys/kern/kern_mutex.c Sun Dec 15 23:28:53 2019 (r355788) +++ head/sys/kern/kern_mutex.c Mon Dec 16 00:04:33 2019 (r355789) @@ -797,10 +797,9 @@ thread_lock_validate(struct mtx *m, int opts, const ch KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, ("thread_lock() of sleep mutex %s @ %s:%d", m->lock_object.lo_name, file, line)); - if (mtx_owned(m)) - KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0, - ("thread_lock: recursed on non-recursive mutex %s @ %s:%d\n", - m->lock_object.lo_name, file, line)); + KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) == 0, + ("thread_lock: got a recursive mutex %s @ %s:%d\n", + m->lock_object.lo_name, file, line)); WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); } @@ -818,7 +817,7 @@ _thread_lock(struct thread *td) #endif { struct mtx *m; - uintptr_t tid, v; + uintptr_t tid; tid = (uintptr_t)curthread; @@ -827,19 +826,14 @@ _thread_lock(struct thread *td) spinlock_enter(); m = td->td_lock; thread_lock_validate(m, 0, file, line); - v = MTX_READ_VALUE(m); - if (__predict_true(v == MTX_UNOWNED)) { - if (__predict_false(!_mtx_obtain_lock(m, tid))) - goto slowpath_unlocked; - } else if (v == tid) { - m->mtx_recurse++; - } else + if (__predict_false(m == &blocked_lock)) goto slowpath_unlocked; + if (__predict_false(!_mtx_obtain_lock(m, tid))) + goto slowpath_unlocked; if (__predict_true(m == td->td_lock)) { WITNESS_LOCK(&m->lock_object, LOP_EXCLUSIVE, file, line); return; } - MPASS(m->mtx_recurse == 0); _mtx_release_lock_quick(m); slowpath_unlocked: spinlock_exit(); @@ -907,11 +901,7 @@ retry: break; continue; } - if (v == tid) { - m->mtx_recurse++; - MPASS(m == td->td_lock); - break; - } + MPASS(v != tid); lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime); /* Give interrupts a chance while we spin. */ @@ -932,7 +922,6 @@ retry: } if (m == td->td_lock) break; - MPASS(m->mtx_recurse == 0); _mtx_release_lock_quick(m); } LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, @@ -946,9 +935,8 @@ retry: #ifdef KDTRACE_HOOKS spin_time += lockstat_nsecs(&m->lock_object); #endif - if (m->mtx_recurse == 0) - LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, m, - contested, waittime, file, line); + LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, m, contested, + waittime, file, line); #ifdef KDTRACE_HOOKS if (lda.spin_cnt != 0) LOCKSTAT_RECORD1(thread__spin, m, spin_time);