From patchwork Tue Jun 23 23:20:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Samuel Thibault X-Patchwork-Id: 1315716 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=sourceware.org (client-ip=8.43.85.97; helo=sourceware.org; envelope-from=libc-alpha-bounces@sourceware.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ens-lyon.org Received: from sourceware.org (server2.sourceware.org [8.43.85.97]) (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) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 49s2MG2QKgz9sPF for ; Wed, 24 Jun 2020 09:20:42 +1000 (AEST) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 52625393C8B0; Tue, 23 Jun 2020 23:20:37 +0000 (GMT) X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from hera.aquilenet.fr (hera.aquilenet.fr [185.233.100.1]) by sourceware.org (Postfix) with ESMTPS id 76B56386F457 for ; Tue, 23 Jun 2020 23:20:34 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 76B56386F457 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=ens-lyon.org Authentication-Results: sourceware.org; spf=fail smtp.mailfrom=samuel.thibault@ens-lyon.org Received: from localhost (localhost [127.0.0.1]) by hera.aquilenet.fr (Postfix) with ESMTP id 6B094E154; Wed, 24 Jun 2020 01:20:33 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at aquilenet.fr Received: from hera.aquilenet.fr ([127.0.0.1]) by localhost (hera.aquilenet.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 612twsf27PR7; Wed, 24 Jun 2020 01:20:32 +0200 (CEST) Received: from function (unknown [IPv6:2a01:cb19:956:1b00:9eb6:d0ff:fe88:c3c7]) by hera.aquilenet.fr (Postfix) with ESMTPSA id D551F4A51; Wed, 24 Jun 2020 01:20:31 +0200 (CEST) Received: from samy by function with local (Exim 4.94) (envelope-from ) id 1jnsDJ-009M2b-54; Wed, 24 Jun 2020 01:20:25 +0200 From: Samuel Thibault To: libc-alpha@sourceware.org Subject: [hurd, commited 1/2] htl: Simplify non-cancel path of __pthread_cond_timedwait_internal Date: Wed, 24 Jun 2020 01:20:23 +0200 Message-Id: <20200623232024.2229631-2-samuel.thibault@ens-lyon.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200623232024.2229631-1-samuel.thibault@ens-lyon.org> References: <20200623232024.2229631-1-samuel.thibault@ens-lyon.org> MIME-Version: 1.0 X-Spam-Status: No, score=-11.2 required=5.0 tests=BAYES_00, GIT_PATCH_0, JMQ_SPF_NEUTRAL, KAM_DMARC_STATUS, SPF_HELO_PASS, SPF_NEUTRAL, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: commit-hurd@gnu.org Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" Since __pthread_exit does not return, we do not need to indent the noncancel path * sysdeps/htl/pt-cond-timedwait.c (__pthread_cond_timedwait_internal): Move cancelled path before non-cancelled path, to avoid "else" indentation. --- sysdeps/htl/pt-cond-timedwait.c | 41 +++++++++++++++++---------------- 1 file changed, 21 insertions(+), 20 deletions(-) diff --git a/sysdeps/htl/pt-cond-timedwait.c b/sysdeps/htl/pt-cond-timedwait.c index c05944d16d..f7801b30ae 100644 --- a/sysdeps/htl/pt-cond-timedwait.c +++ b/sysdeps/htl/pt-cond-timedwait.c @@ -117,29 +117,30 @@ __pthread_cond_timedwait_internal (pthread_cond_t *cond, cancelled = (self->cancel_state == PTHREAD_CANCEL_ENABLE) && self->cancel_pending; - if (!cancelled) + if (cancelled) { - self->cancel_hook = cancel_hook; - self->cancel_hook_arg = &ctx; - oldtype = self->cancel_type; - - if (oldtype != PTHREAD_CANCEL_DEFERRED) - self->cancel_type = PTHREAD_CANCEL_DEFERRED; - - /* Add ourselves to the list of waiters. This is done while setting - the cancellation hook to simplify the cancellation procedure, i.e. - if the thread is queued, it can be cancelled, otherwise it is - already unblocked, progressing on the return path. */ - __pthread_spin_wait (&cond->__lock); - __pthread_enqueue (&cond->__queue, self); - if (cond->__attr != NULL && clockid == -1) - clock_id = cond->__attr->__clock; - __pthread_spin_unlock (&cond->__lock); + __pthread_mutex_unlock (&self->cancel_lock); + __pthread_exit (PTHREAD_CANCELED); } - __pthread_mutex_unlock (&self->cancel_lock); - if (cancelled) - __pthread_exit (PTHREAD_CANCELED); + self->cancel_hook = cancel_hook; + self->cancel_hook_arg = &ctx; + oldtype = self->cancel_type; + + if (oldtype != PTHREAD_CANCEL_DEFERRED) + self->cancel_type = PTHREAD_CANCEL_DEFERRED; + + /* Add ourselves to the list of waiters. This is done while setting + the cancellation hook to simplify the cancellation procedure, i.e. + if the thread is queued, it can be cancelled, otherwise it is + already unblocked, progressing on the return path. */ + __pthread_spin_wait (&cond->__lock); + __pthread_enqueue (&cond->__queue, self); + if (cond->__attr != NULL && clockid == -1) + clock_id = cond->__attr->__clock; + __pthread_spin_unlock (&cond->__lock); + + __pthread_mutex_unlock (&self->cancel_lock); /* Release MUTEX before blocking. */ __pthread_mutex_unlock (mutex); From patchwork Tue Jun 23 23:20:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Samuel Thibault X-Patchwork-Id: 1315717 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=sourceware.org (client-ip=8.43.85.97; helo=sourceware.org; envelope-from=libc-alpha-bounces@sourceware.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ens-lyon.org Received: from sourceware.org (server2.sourceware.org [8.43.85.97]) (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) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 49s2ML2VQBz9sPF for ; Wed, 24 Jun 2020 09:20:46 +1000 (AEST) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id B4C2D394844B; Tue, 23 Jun 2020 23:20:38 +0000 (GMT) X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from hera.aquilenet.fr (hera.aquilenet.fr [185.233.100.1]) by sourceware.org (Postfix) with ESMTPS id A305D3840C3B for ; Tue, 23 Jun 2020 23:20:35 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org A305D3840C3B Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=ens-lyon.org Authentication-Results: sourceware.org; spf=fail smtp.mailfrom=samuel.thibault@ens-lyon.org Received: from localhost (localhost [127.0.0.1]) by hera.aquilenet.fr (Postfix) with ESMTP id A493D4A51; Wed, 24 Jun 2020 01:20:34 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at aquilenet.fr Received: from hera.aquilenet.fr ([127.0.0.1]) by localhost (hera.aquilenet.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id dcBJlVVetWwT; Wed, 24 Jun 2020 01:20:33 +0200 (CEST) Received: from function (unknown [IPv6:2a01:cb19:956:1b00:9eb6:d0ff:fe88:c3c7]) by hera.aquilenet.fr (Postfix) with ESMTPSA id 0EC1E10788; Wed, 24 Jun 2020 01:20:31 +0200 (CEST) Received: from samy by function with local (Exim 4.94) (envelope-from ) id 1jnsDJ-009M2e-75; Wed, 24 Jun 2020 01:20:25 +0200 From: Samuel Thibault To: libc-alpha@sourceware.org Subject: [hurd,commited 2/2] htl: Make sem_*wait cancellations points Date: Wed, 24 Jun 2020 01:20:24 +0200 Message-Id: <20200623232024.2229631-3-samuel.thibault@ens-lyon.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200623232024.2229631-1-samuel.thibault@ens-lyon.org> References: <20200623232024.2229631-1-samuel.thibault@ens-lyon.org> MIME-Version: 1.0 X-Spam-Status: No, score=-11.2 required=5.0 tests=BAYES_00, GIT_PATCH_0, JMQ_SPF_NEUTRAL, KAM_DMARC_STATUS, SPF_HELO_PASS, SPF_NEUTRAL, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: commit-hurd@gnu.org Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" By aligning its implementation on pthread_cond_wait. * sysdeps/htl/sem-timedwait.c (cancel_ctx): New structure. (cancel_hook): New function. (__sem_timedwait_internal): Check for cancellation and register cancellation hook that wakes the thread up, and check again for cancellation on exit. * nptl/tst-cancel13.c, nptl/tst-cancelx13.c: Move to... * sysdeps/pthread/: ... here. * nptl/Makefile: Move corresponding references and rules to... * sysdeps/pthread/Makefile: ... here. --- nptl/Makefile | 4 +- sysdeps/htl/sem-timedwait.c | 92 +++++++++++++++++++++-- sysdeps/pthread/Makefile | 9 ++- {nptl => sysdeps/pthread}/tst-cancel13.c | 0 {nptl => sysdeps/pthread}/tst-cancelx13.c | 0 5 files changed, 90 insertions(+), 15 deletions(-) rename {nptl => sysdeps/pthread}/tst-cancel13.c (100%) rename {nptl => sysdeps/pthread}/tst-cancelx13.c (100%) diff --git a/nptl/Makefile b/nptl/Makefile index 24ebd07a30..4602824bf1 100644 --- a/nptl/Makefile +++ b/nptl/Makefile @@ -278,7 +278,7 @@ tests = tst-attr2 tst-attr3 tst-default-attr \ tst-sem17 \ tst-tsd3 tst-tsd4 \ tst-cancel4 tst-cancel4_1 tst-cancel4_2 tst-cancel5 \ - tst-cancel7 tst-cancel13 \ + tst-cancel7 \ tst-cancel16 tst-cancel17 tst-cancel20 tst-cancel24 \ tst-cleanup4 \ tst-signal3 \ @@ -358,7 +358,6 @@ endif LDFLAGS-pthread.so = -Wl,--enable-new-dtags,-z,nodelete,-z,initfirst tests += tst-cancelx4 tst-cancelx5 tst-cancelx7 \ - tst-cancelx13 \ tst-cancelx16 tst-cancelx17 tst-cancelx20 \ tst-cleanupx4 @@ -477,7 +476,6 @@ CFLAGS-tst-cancelx5.c += -Wno-error CFLAGS-tst-cancelx4.c += -fexceptions CFLAGS-tst-cancelx5.c += -fexceptions CFLAGS-tst-cancelx7.c += -fexceptions -CFLAGS-tst-cancelx13.c += -fexceptions CFLAGS-tst-cancelx16.c += -fexceptions CFLAGS-tst-cancelx17.c += -fexceptions CFLAGS-tst-cancelx20.c += -fexceptions -fasynchronous-unwind-tables diff --git a/sysdeps/htl/sem-timedwait.c b/sysdeps/htl/sem-timedwait.c index 0b1b6d0961..691fb7e5ee 100644 --- a/sysdeps/htl/sem-timedwait.c +++ b/sysdeps/htl/sem-timedwait.c @@ -23,36 +23,98 @@ #include +struct cancel_ctx +{ + struct __pthread *wakeup; + sem_t *sem; +}; + +static void +cancel_hook (void *arg) +{ + struct cancel_ctx *ctx = arg; + struct __pthread *wakeup = ctx->wakeup; + sem_t *sem = ctx->sem; + int unblock; + + __pthread_spin_wait (&sem->__lock); + /* The thread only needs to be awaken if it's blocking or about to block. + If it was already unblocked, it's not queued any more. */ + unblock = wakeup->prevp != NULL; + if (unblock) + __pthread_dequeue (wakeup); + __pthread_spin_unlock (&sem->__lock); + + if (unblock) + __pthread_wakeup (wakeup); +} + int __sem_timedwait_internal (sem_t *restrict sem, clockid_t clock_id, const struct timespec *restrict timeout) { error_t err; - int drain; - struct __pthread *self; + int cancelled, oldtype, drain; + int ret = 0; + + struct __pthread *self = _pthread_self (); + struct cancel_ctx ctx; + ctx.wakeup = self; + ctx.sem = sem; + + /* Test for a pending cancellation request, switch to deferred mode for + safer resource handling, and prepare the hook to call in case we're + cancelled while blocking. Once CANCEL_LOCK is released, the cancellation + hook can be called by another thread at any time. Whatever happens, + this function must exit with MUTEX locked. + + This function contains inline implementations of pthread_testcancel and + pthread_setcanceltype to reduce locking overhead. */ + __pthread_mutex_lock (&self->cancel_lock); + cancelled = (self->cancel_state == PTHREAD_CANCEL_ENABLE) + && self->cancel_pending; + + if (cancelled) + { + __pthread_mutex_unlock (&self->cancel_lock); + __pthread_exit (PTHREAD_CANCELED); + } + + self->cancel_hook = cancel_hook; + self->cancel_hook_arg = &ctx; + oldtype = self->cancel_type; + if (oldtype != PTHREAD_CANCEL_DEFERRED) + self->cancel_type = PTHREAD_CANCEL_DEFERRED; + + /* Add ourselves to the list of waiters. This is done while setting + the cancellation hook to simplify the cancellation procedure, i.e. + if the thread is queued, it can be cancelled, otherwise it is + already unblocked, progressing on the return path. */ __pthread_spin_wait (&sem->__lock); if (sem->__value > 0) /* Successful down. */ { sem->__value--; __pthread_spin_unlock (&sem->__lock); - return 0; + goto out_locked; } if (timeout != NULL && ! valid_nanoseconds (timeout->tv_nsec)) { errno = EINVAL; - return -1; + ret = -1; + __pthread_spin_unlock (&sem->__lock); + goto out_locked; } /* Add ourselves to the queue. */ - self = _pthread_self (); - __pthread_enqueue (&sem->__queue, self); __pthread_spin_unlock (&sem->__lock); + __pthread_mutex_unlock (&self->cancel_lock); + /* Block the thread. */ if (timeout != NULL) err = __pthread_timedblock_intr (self, timeout, clock_id); @@ -82,10 +144,24 @@ __sem_timedwait_internal (sem_t *restrict sem, { assert (err == ETIMEDOUT || err == EINTR); errno = err; - return -1; + ret = -1; } - return 0; + /* We're almost done. Remove the unblock hook, restore the previous + cancellation type, and check for a pending cancellation request. */ + __pthread_mutex_lock (&self->cancel_lock); +out_locked: + self->cancel_hook = NULL; + self->cancel_hook_arg = NULL; + self->cancel_type = oldtype; + cancelled = (self->cancel_state == PTHREAD_CANCEL_ENABLE) + && self->cancel_pending; + __pthread_mutex_unlock (&self->cancel_lock); + + if (cancelled) + __pthread_exit (PTHREAD_CANCELED); + + return ret; } int diff --git a/sysdeps/pthread/Makefile b/sysdeps/pthread/Makefile index 01602e69d5..ed31ae8f4f 100644 --- a/sysdeps/pthread/Makefile +++ b/sysdeps/pthread/Makefile @@ -55,8 +55,8 @@ tests += tst-cnd-basic tst-mtx-trylock tst-cnd-broadcast \ tst-cancel-self-canceltype tst-cancel-self-testcancel \ tst-cancel1 tst-cancel2 tst-cancel3 \ tst-cancel6 tst-cancel8 tst-cancel9 tst-cancel10 tst-cancel11 \ - tst-cancel12 tst-cancel14 tst-cancel15 tst-cancel18 tst-cancel19 \ - tst-cancel21 \ + tst-cancel12 tst-cancel13 tst-cancel14 tst-cancel15 tst-cancel18 \ + tst-cancel19 tst-cancel21 \ tst-cancel22 tst-cancel23 tst-cancel26 tst-cancel27 tst-cancel28 \ tst-cleanup0 tst-cleanup1 tst-cleanup2 tst-cleanup3 \ tst-clock1 \ @@ -117,8 +117,8 @@ CFLAGS-tst-cleanup2.c += -fno-builtin CFLAGS-tst-cleanupx2.c += -fno-builtin tests += tst-cancelx2 tst-cancelx3 tst-cancelx6 tst-cancelx8 tst-cancelx9 \ - tst-cancelx10 tst-cancelx11 tst-cancelx12 tst-cancelx14 tst-cancelx15 \ - tst-cancelx18 tst-cancelx21 \ + tst-cancelx10 tst-cancelx11 tst-cancelx12 tst-cancelx13 tst-cancelx14 \ + tst-cancelx15 tst-cancelx18 tst-cancelx21 \ tst-cleanupx0 tst-cleanupx1 tst-cleanupx2 tst-cleanupx3 ifeq ($(build-shared),yes) @@ -160,6 +160,7 @@ CFLAGS-tst-cancelx9.c += -fexceptions CFLAGS-tst-cancelx10.c += -fexceptions CFLAGS-tst-cancelx11.c += -fexceptions CFLAGS-tst-cancelx12.c += -fexceptions +CFLAGS-tst-cancelx13.c += -fexceptions CFLAGS-tst-cancelx14.c += -fexceptions CFLAGS-tst-cancelx15.c += -fexceptions CFLAGS-tst-cancelx18.c += -fexceptions diff --git a/nptl/tst-cancel13.c b/sysdeps/pthread/tst-cancel13.c similarity index 100% rename from nptl/tst-cancel13.c rename to sysdeps/pthread/tst-cancel13.c diff --git a/nptl/tst-cancelx13.c b/sysdeps/pthread/tst-cancelx13.c similarity index 100% rename from nptl/tst-cancelx13.c rename to sysdeps/pthread/tst-cancelx13.c