From owner-dev-commits-src-branches@freebsd.org Mon Jun 7 16:33:08 2021 Return-Path: Delivered-To: dev-commits-src-branches@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 3CC1465005F; Mon, 7 Jun 2021 16:33:08 +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 4FzJnw04bMz3RHq; Mon, 7 Jun 2021 16:33:08 +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 DCCE318DD6; Mon, 7 Jun 2021 16:33:07 +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 157GX7ol004170; Mon, 7 Jun 2021 16:33:07 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 157GX7pL004169; Mon, 7 Jun 2021 16:33:07 GMT (envelope-from git) Date: Mon, 7 Jun 2021 16:33:07 GMT Message-Id: <202106071633.157GX7pL004169@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Konstantin Belousov Subject: git: 8c30192804eb - stable/13 - Add thread_reap_barrier() MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: kib X-Git-Repository: src X-Git-Refname: refs/heads/stable/13 X-Git-Reftype: branch X-Git-Commit: 8c30192804eb91b2b976e92d0ca52fd034520062 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-branches@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commits to the stable branches of the FreeBSD src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 Jun 2021 16:33:08 -0000 The branch stable/13 has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=8c30192804eb91b2b976e92d0ca52fd034520062 commit 8c30192804eb91b2b976e92d0ca52fd034520062 Author: Konstantin Belousov AuthorDate: 2021-05-25 18:51:00 +0000 Commit: Konstantin Belousov CommitDate: 2021-06-07 16:32:42 +0000 Add thread_reap_barrier() (cherry picked from commit f62c7e54e9cc692603081328597ba0ba0d1f21cf) (cherry picked from commit d3f7975fcb346ea28dde079a9c04cff5ef20a8d7) --- sys/kern/kern_thread.c | 29 +++++++++++++++++++++++++++++ sys/sys/proc.h | 1 + 2 files changed, 30 insertions(+) diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c index 7370fd919203..48aac8e057b8 100644 --- a/sys/kern/kern_thread.c +++ b/sys/kern/kern_thread.c @@ -709,6 +709,35 @@ thread_reap_callout_cb(void *arg __unused) thread_reap_callout_cb, NULL); } +/* + * Calling this function guarantees that any thread that exited before + * the call is reaped when the function returns. By 'exited' we mean + * a thread removed from the process linkage with thread_unlink(). + * Practically this means that caller must lock/unlock corresponding + * process lock before the call, to synchronize with thread_exit(). + */ +void +thread_reap_barrier(void) +{ + struct task *t; + + /* + * First do context switches to each CPU to ensure that all + * PCPU pc_deadthreads are moved to zombie list. + */ + quiesce_all_cpus("", PDROP); + + /* + * Second, fire the task in the same thread as normal + * thread_reap() is done, to serialize reaping. + */ + t = malloc(sizeof(*t), M_TEMP, M_WAITOK); + TASK_INIT(t, 0, thread_reap_task_cb, t); + taskqueue_enqueue(taskqueue_thread, t); + taskqueue_drain(taskqueue_thread, t); + free(t, M_TEMP); +} + /* * Allocate a thread. */ diff --git a/sys/sys/proc.h b/sys/sys/proc.h index 7a2210778a39..b0fc13a449cb 100644 --- a/sys/sys/proc.h +++ b/sys/sys/proc.h @@ -1177,6 +1177,7 @@ int thread_create(struct thread *td, struct rtprio *rtp, void thread_exit(void) __dead2; void thread_free(struct thread *td); void thread_link(struct thread *td, struct proc *p); +void thread_reap_barrier(void); int thread_single(struct proc *p, int how); void thread_single_end(struct proc *p, int how); void thread_stash(struct thread *td);