From: Darren Hart <dvhltc@us.ibm.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, dvhltc@us.ibm.com, hpa@zytor.com,
mingo@redhat.com, rusty@rustcorp.com.au, peterz@infradead.org,
tglx@linutronix.de, mingo@elte.hu
Subject: [tip:core/futexes] futex: add double_unlock_hb()
Date: Thu, 12 Mar 2009 10:24:44 GMT [thread overview]
Message-ID: <tip-5eb3dc62fc5986e85715041c23dcf3832812be4b@git.kernel.org> (raw)
In-Reply-To: <20090312075552.9856.48021.stgit@Aeon>
Commit-ID: 5eb3dc62fc5986e85715041c23dcf3832812be4b
Gitweb: http://git.kernel.org/tip/5eb3dc62fc5986e85715041c23dcf3832812be4b
Author: "Darren Hart" <dvhltc@us.ibm.com>
AuthorDate: Thu, 12 Mar 2009 00:55:52 -0700
Commit: Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 12 Mar 2009 11:20:56 +0100
futex: add double_unlock_hb()
Impact: cleanup
The futex code uses double_lock_hb() which locks the hb->lock's
in pointer value order. There is no parallel unlock routine,
and the code unlocks them in name order, ignoring pointer value.
This patch adds double_unlock_hb() to refactor the duplicated
code segments.
Build and boot tested on a 4 way Intel x86_64 workstation.
Passes basic pthread_mutex and PI tests out of
ltp/testcases/realtime.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <20090312075552.9856.48021.stgit@Aeon>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/futex.c | 29 +++++++++++++++++------------
1 files changed, 17 insertions(+), 12 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c
index 4000454..e149545 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -690,6 +690,19 @@ double_lock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2)
}
}
+static inline void
+double_unlock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2)
+{
+ if (hb1 <= hb2) {
+ spin_unlock(&hb2->lock);
+ if (hb1 < hb2)
+ spin_unlock(&hb1->lock);
+ } else { /* hb1 > hb2 */
+ spin_unlock(&hb1->lock);
+ spin_unlock(&hb2->lock);
+ }
+}
+
/*
* Wake up waiters matching bitset queued on this futex (uaddr).
*/
@@ -767,9 +780,7 @@ retry:
if (unlikely(op_ret < 0)) {
u32 dummy;
- spin_unlock(&hb1->lock);
- if (hb1 != hb2)
- spin_unlock(&hb2->lock);
+ double_unlock_hb(hb1, hb2);
#ifndef CONFIG_MMU
/*
@@ -833,9 +844,7 @@ retry:
ret += op_ret;
}
- spin_unlock(&hb1->lock);
- if (hb1 != hb2)
- spin_unlock(&hb2->lock);
+ double_unlock_hb(hb1, hb2);
out_put_keys:
put_futex_key(fshared, &key2);
out_put_key1:
@@ -876,9 +885,7 @@ retry:
ret = get_futex_value_locked(&curval, uaddr1);
if (unlikely(ret)) {
- spin_unlock(&hb1->lock);
- if (hb1 != hb2)
- spin_unlock(&hb2->lock);
+ double_unlock_hb(hb1, hb2);
put_futex_key(fshared, &key2);
put_futex_key(fshared, &key1);
@@ -925,9 +932,7 @@ retry:
}
out_unlock:
- spin_unlock(&hb1->lock);
- if (hb1 != hb2)
- spin_unlock(&hb2->lock);
+ double_unlock_hb(hb1, hb2);
/* drop_futex_key_refs() must be called outside the spinlocks. */
while (--drop_count >= 0)
next prev parent reply other threads:[~2009-03-12 10:26 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-12 7:55 [PATCH 0/6] Futex fixes and cleanups Darren Hart
2009-03-12 7:55 ` [PATCH 1/6] Update futex commentary Darren Hart
2009-03-12 10:24 ` [tip:core/futexes] futex: update " Darren Hart
2009-03-12 7:55 ` [PATCH 2/6] Additional (get|put)_futex_key() fixes Darren Hart
2009-03-12 10:16 ` Ingo Molnar
2009-03-12 13:42 ` Thomas Gleixner
2009-03-12 23:22 ` Darren Hart
2009-03-12 10:24 ` [tip:core/futexes] futex: additional " Darren Hart
2009-03-13 0:20 ` Ingo Molnar
2009-03-13 5:46 ` Darren Hart
2009-03-13 0:24 ` [tip:core/urgent] " Darren Hart
2009-03-12 7:55 ` [PATCH 3/6] futex: add double_unlock_hb() Darren Hart
2009-03-12 10:07 ` Peter Zijlstra
2009-03-12 10:10 ` Ingo Molnar
2009-03-12 10:58 ` Thomas Gleixner
2009-03-12 15:13 ` Darren Hart
2009-03-12 10:24 ` Darren Hart [this message]
2009-03-12 7:55 ` [PATCH 4/6] futex: Use current->time_slack_ns for rt tasks too Darren Hart
2009-03-12 10:11 ` Peter Zijlstra
2009-03-12 10:24 ` [tip:core/futexes] futex: use " Darren Hart
2009-03-12 13:53 ` Arjan van de Ven
2009-03-12 14:02 ` Peter Zijlstra
2009-03-12 14:25 ` Thomas Gleixner
2009-03-12 14:48 ` Peter Zijlstra
2009-03-12 15:01 ` Arjan van de Ven
2009-03-12 21:33 ` Darren Hart
2009-03-12 21:43 ` Thomas Gleixner
2009-03-12 21:29 ` Darren Hart
2009-03-12 7:56 ` [PATCH 5/6] futex: unlock before returning -EFAULT Darren Hart
2009-03-12 10:13 ` Peter Zijlstra
2009-03-12 10:47 ` Thomas Gleixner
2009-03-12 11:06 ` Peter Zijlstra
2009-03-12 15:15 ` Darren Hart
2009-03-12 22:17 ` Darren Hart
2009-03-12 10:24 ` [tip:core/futexes] " Darren Hart
2009-03-13 0:24 ` [tip:core/urgent] " Darren Hart
2009-03-12 7:56 ` [PATCH 6/6] futex: cleanup fault logic Darren Hart
2009-03-12 10:15 ` Peter Zijlstra
2009-03-12 15:09 ` Darren Hart
2009-03-12 10:25 ` [tip:core/futexes] futex: clean up " Darren Hart
2009-03-12 12:22 ` [PATCH 0/6] Futex fixes and cleanups Ingo Molnar
2009-03-12 15:21 ` Darren Hart
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