Return-Path: linux-nfs-owner@vger.kernel.org Received: from cantor2.suse.de ([195.135.220.15]:51857 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752738AbaIXCDO (ORCPT ); Tue, 23 Sep 2014 22:03:14 -0400 From: NeilBrown To: Trond Myklebust Date: Wed, 24 Sep 2014 11:28:32 +1000 Subject: [PATCH 1/5] SCHED: add some "wait..on_bit...timeout()" interfaces. Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ingo Molnar , linux-fsdevel@vger.kernel.org, Andrew Morton , Jeff Layton , Peter Zijlstra Message-ID: <20140924012832.4838.59410.stgit@notabene.brown> In-Reply-To: <20140924012422.4838.29188.stgit@notabene.brown> References: <20140924012422.4838.29188.stgit@notabene.brown> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: In commit c1221321b7c25b53204447cff9949a6d5a7ddddc sched: Allow wait_on_bit_action() functions to support a timeout I suggested that a "wait_on_bit_timeout()" interface would not meet my need. This isn't true - I was just over-engineering. Including a 'private' field in wait_bit_key instead of a focused "timeout" field was just premature generalization. If some other use is ever found, it can be generalized or added later. So this patch renames "private" to "timeout" with a meaning "stop waiting when "jiffies" reaches or passes "timeout", and adds two of the many possible wait..bit..timeout() interfaces: wait_on_page_bit_killable_timeout(), which is the one I want to use, and out_of_line_wait_on_bit_timeout() which is a reasonably general example. Others can be added as needed. Acked-by: Peter Zijlstra (Intel) Signed-off-by: NeilBrown --- include/linux/pagemap.h | 2 ++ include/linux/wait.h | 5 ++++- kernel/sched/wait.c | 36 ++++++++++++++++++++++++++++++++++++ mm/filemap.c | 13 +++++++++++++ 4 files changed, 55 insertions(+), 1 deletion(-) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 3df8c7db7a4e..87f9e4230d3a 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -502,6 +502,8 @@ static inline int lock_page_or_retry(struct page *page, struct mm_struct *mm, extern void wait_on_page_bit(struct page *page, int bit_nr); extern int wait_on_page_bit_killable(struct page *page, int bit_nr); +extern int wait_on_page_bit_killable_timeout(struct page *page, + int bit_nr, unsigned long timeout); static inline int wait_on_page_locked_killable(struct page *page) { diff --git a/include/linux/wait.h b/include/linux/wait.h index 6fb1ba5f9b2f..80115bf88671 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -25,7 +25,7 @@ struct wait_bit_key { void *flags; int bit_nr; #define WAIT_ATOMIC_T_BIT_NR -1 - unsigned long private; + unsigned long timeout; }; struct wait_bit_queue { @@ -154,6 +154,7 @@ int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_ac void wake_up_bit(void *, int); void wake_up_atomic_t(atomic_t *); int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned); +int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long); int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned); int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned); wait_queue_head_t *bit_waitqueue(void *, int); @@ -859,6 +860,8 @@ int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key); extern int bit_wait(struct wait_bit_key *); extern int bit_wait_io(struct wait_bit_key *); +extern int bit_wait_timeout(struct wait_bit_key *); +extern int bit_wait_io_timeout(struct wait_bit_key *); /** * wait_on_bit - wait for a bit to be cleared diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index 15cab1a4f84e..380678b3cba4 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -343,6 +343,18 @@ int __sched out_of_line_wait_on_bit(void *word, int bit, } EXPORT_SYMBOL(out_of_line_wait_on_bit); +int __sched out_of_line_wait_on_bit_timeout( + void *word, int bit, wait_bit_action_f *action, + unsigned mode, unsigned long timeout) +{ + wait_queue_head_t *wq = bit_waitqueue(word, bit); + DEFINE_WAIT_BIT(wait, word, bit); + + wait.key.timeout = jiffies + timeout; + return __wait_on_bit(wq, &wait, action, mode); +} +EXPORT_SYMBOL(out_of_line_wait_on_bit_timeout); + int __sched __wait_on_bit_lock(wait_queue_head_t *wq, struct wait_bit_queue *q, wait_bit_action_f *action, unsigned mode) @@ -520,3 +532,27 @@ __sched int bit_wait_io(struct wait_bit_key *word) return 0; } EXPORT_SYMBOL(bit_wait_io); + +__sched int bit_wait_timeout(struct wait_bit_key *word) +{ + unsigned long now = ACCESS_ONCE(jiffies); + if (signal_pending_state(current->state, current)) + return 1; + if (time_after_eq(now, word->timeout)) + return -EAGAIN; + schedule_timeout(word->timeout - now); + return 0; +} +EXPORT_SYMBOL(bit_wait_timeout); + +__sched int bit_wait_io_timeout(struct wait_bit_key *word) +{ + unsigned long now = ACCESS_ONCE(jiffies); + if (signal_pending_state(current->state, current)) + return 1; + if (time_after_eq(now, word->timeout)) + return -EAGAIN; + io_schedule_timeout(word->timeout - now); + return 0; +} +EXPORT_SYMBOL(bit_wait_io_timeout); diff --git a/mm/filemap.c b/mm/filemap.c index 90effcdf948d..4a19c084bdb1 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -703,6 +703,19 @@ int wait_on_page_bit_killable(struct page *page, int bit_nr) bit_wait_io, TASK_KILLABLE); } +int wait_on_page_bit_killable_timeout(struct page *page, + int bit_nr, unsigned long timeout) +{ + DEFINE_WAIT_BIT(wait, &page->flags, bit_nr); + + wait.key.timeout = jiffies + timeout; + if (!test_bit(bit_nr, &page->flags)) + return 0; + return __wait_on_bit(page_waitqueue(page), &wait, + bit_wait_io_timeout, TASK_KILLABLE); +} +EXPORT_SYMBOL(wait_on_page_bit_killable_timeout); + /** * add_page_wait_queue - Add an arbitrary waiter to a page's wait queue * @page: Page defining the wait queue of interest