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Fri, 19 Jun 2020 08:30:25 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id D136630604B; Fri, 19 Jun 2020 10:30:23 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id C27DD2038B22F; Fri, 19 Jun 2020 10:30:23 +0200 (CEST) Date: Fri, 19 Jun 2020 10:30:23 +0200 From: Peter Zijlstra To: Axel Rasmussen Cc: Michel Lespinasse , David Howells , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Jonathan Adams , David Rientjes , Ying Han Subject: Re: [RFC PATCH v3 1/1] mmap_lock: add tracepoints around mmap_lock acquisition Message-ID: <20200619083023.GS576905@hirez.programming.kicks-ass.net> References: <20200618222225.102337-1-axelrasmussen@google.com> <20200618222225.102337-2-axelrasmussen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200618222225.102337-2-axelrasmussen@google.com> X-Rspamd-Queue-Id: 62E0F180FA2BB X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Jun 18, 2020 at 03:22:25PM -0700, Axel Rasmussen wrote: > diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c > index f11b9bd3431d..6aabea1cbc5d 100644 > --- a/kernel/locking/rwsem.c > +++ b/kernel/locking/rwsem.c > @@ -1495,6 +1495,20 @@ void __sched down_read(struct rw_semaphore *sem) > } > EXPORT_SYMBOL(down_read); > > +/* > + * lock for reading > + */ > +void __sched down_read_contended_hook(struct rw_semaphore *sem, > + void (*pre)(void *), > + void (*post)(void *), void *arg) > +{ > + might_sleep(); > + rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_); > + LOCK_CONTENDED_HOOK(sem, __down_read_trylock, __down_read, pre, post, > + arg); > +} > +EXPORT_SYMBOL(down_read_contended_hook); > + > int __sched down_read_killable(struct rw_semaphore *sem) > { > might_sleep(); > @@ -1509,6 +1523,24 @@ int __sched down_read_killable(struct rw_semaphore *sem) > } > EXPORT_SYMBOL(down_read_killable); > > +int __sched down_read_killable_contended_hook(struct rw_semaphore *sem, > + void (*pre)(void *), > + void (*post)(void *, int), > + void *arg) > +{ > + might_sleep(); > + rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_); > + > + if (LOCK_CONTENDED_HOOK_RETURN(sem, __down_read_trylock, > + __down_read_killable, pre, post, arg)) { > + rwsem_release(&sem->dep_map, _RET_IP_); > + return -EINTR; > + } > + > + return 0; > +} > +EXPORT_SYMBOL(down_read_killable_contended_hook); > + > /* > * trylock for reading -- returns 1 if successful, 0 if contention > */ > @@ -1533,6 +1565,20 @@ void __sched down_write(struct rw_semaphore *sem) > } > EXPORT_SYMBOL(down_write); > > +/* > + * lock for writing > + */ > +void __sched down_write_contended_hook(struct rw_semaphore *sem, > + void (*pre)(void *), > + void (*post)(void *), void *arg) > +{ > + might_sleep(); > + rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_); > + LOCK_CONTENDED_HOOK(sem, __down_write_trylock, __down_write, pre, post, > + arg); > +} > +EXPORT_SYMBOL(down_write_contended_hook); > + > /* > * lock for writing > */ > @@ -1551,6 +1597,24 @@ int __sched down_write_killable(struct rw_semaphore *sem) > } > EXPORT_SYMBOL(down_write_killable); > > +int __sched down_write_killable_contended_hook(struct rw_semaphore *sem, > + void (*pre)(void *), > + void (*post)(void *, int), > + void *arg) > +{ > + might_sleep(); > + rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_); > + > + if (LOCK_CONTENDED_HOOK_RETURN(sem, __down_write_trylock, > + __down_write_killable, pre, post, arg)) { > + rwsem_release(&sem->dep_map, _RET_IP_); > + return -EINTR; > + } > + > + return 0; > +} > +EXPORT_SYMBOL(down_write_killable_contended_hook); > + > /* > * trylock for writing -- returns 1 if successful, 0 if contention > */ NAK, absolutely not going to happen. This is an atrocious API to expose, worse you're exporting.