From: Peter Zijlstra <peterz@infradead.org>
To: torvalds@linux-foundation.org, mingo@kernel.org,
tglx@linutronix.de, will.deacon@arm.com,
paulmck@linux.vnet.ibm.com, boqun.feng@gmail.com,
waiman.long@hpe.com, fweisbec@gmail.com
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
rth@twiddle.net, vgupta@synopsys.com, linux@arm.linux.org.uk,
egtvedt@samfundet.no, realmz6@gmail.com,
ysato@users.sourceforge.jp, rkuo@codeaurora.org,
tony.luck@intel.com, geert@linux-m68k.org,
james.hogan@imgtec.com, ralf@linux-mips.org, dhowells@redhat.com,
jejb@parisc-linux.org, mpe@ellerman.id.au,
schwidefsky@de.ibm.com, dalias@libc.org, davem@davemloft.net,
cmetcalf@mellanox.com, jcmvbkbc@gmail.com, arnd@arndb.de,
peterz@infradead.org, dbueso@suse.de, fengguang.wu@intel.com
Subject: [PATCH -v2 32/33] locking,qrwlock: Employ atomic_fetch_add_acquire()
Date: Tue, 31 May 2016 12:19:57 +0200 [thread overview]
Message-ID: <20160531102643.459595230@infradead.org> (raw)
In-Reply-To: 20160531101925.702692792@infradead.org
[-- Attachment #1: peterz-locking-qspinlock-fetch-add.patch --]
[-- Type: text/plain, Size: 794 bytes --]
The only reason for the current code is to make GCC emit only the
"LOCK XADD" instruction on x86 (and not do a pointless extra ADD on
the result), do so nicer.
Acked-by: Waiman Long <waiman.long@hpe.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/locking/qrwlock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/locking/qrwlock.c
+++ b/kernel/locking/qrwlock.c
@@ -93,7 +93,7 @@ void queued_read_lock_slowpath(struct qr
* that accesses can't leak upwards out of our subsequent critical
* section in the case that the lock is currently held for write.
*/
- cnts = atomic_add_return_acquire(_QR_BIAS, &lock->cnts) - _QR_BIAS;
+ cnts = atomic_fetch_add_acquire(_QR_BIAS, &lock->cnts);
rspin_until_writer_unlock(lock, cnts);
/*
next prev parent reply other threads:[~2016-05-31 10:19 UTC|newest]
Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-31 10:19 [PATCH -v2 00/33] implement atomic_fetch_$op Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 01/33] locking,alpha: Implement atomic{,64}_fetch_{add,sub,and,andnot,or,xor}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 02/33] locking,arc: Implement atomic_fetch_{add,sub,and,andnot,or,xor}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 03/33] locking,arm: Implement atomic{,64}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 04/33] locking,arm64: " Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 05/33] arm64: atomic: generate LSE non-return cases using common macros Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 06/33] locking,arm64: Implement atomic{,64}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}() for LSE instructions Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 07/33] locking,avr32: Implement atomic_fetch_{add,sub,and,or,xor}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 08/33] locking,blackfin: " Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 09/33] locking,frv: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 10/33] locking,h8300: Implement atomic_fetch_{add,sub,and,or,xor}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 11/33] locking,hexagon: " Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 12/33] locking,ia64: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 13/33] locking,m32r: Implement atomic_fetch_{add,sub,and,or,xor}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 14/33] locking,m68k: " Peter Zijlstra
2016-06-16 10:08 ` Geert Uytterhoeven
2016-06-16 10:08 ` Geert Uytterhoeven
2016-06-16 10:08 ` Geert Uytterhoeven
2016-06-16 10:13 ` Peter Zijlstra
2016-06-16 10:13 ` Peter Zijlstra
2016-06-16 10:13 ` Peter Zijlstra
2016-06-16 12:43 ` Andreas Schwab
2016-06-16 12:43 ` Andreas Schwab
2016-06-16 12:43 ` Andreas Schwab
2016-06-16 12:49 ` Peter Zijlstra
2016-06-16 12:49 ` Peter Zijlstra
2016-06-16 12:49 ` Peter Zijlstra
2016-06-16 12:49 ` Peter Zijlstra
2016-06-16 12:53 ` Andreas Schwab
2016-06-16 12:53 ` Andreas Schwab
2016-06-16 12:53 ` Andreas Schwab
2016-06-16 12:53 ` Andreas Schwab
2016-06-16 14:35 ` Peter Zijlstra
2016-06-16 14:35 ` Peter Zijlstra
2016-06-16 14:35 ` Peter Zijlstra
2016-06-16 14:37 ` Andreas Schwab
2016-06-16 14:37 ` Andreas Schwab
2016-06-16 14:37 ` Andreas Schwab
2016-06-16 14:56 ` Peter Zijlstra
2016-06-16 14:56 ` Peter Zijlstra
2016-06-16 14:56 ` Peter Zijlstra
2016-06-16 15:04 ` Andreas Schwab
2016-06-16 15:04 ` Andreas Schwab
2016-06-16 15:04 ` Andreas Schwab
2016-06-16 15:04 ` Andreas Schwab
2016-06-16 17:44 ` Peter Zijlstra
2016-06-16 17:44 ` Peter Zijlstra
2016-06-16 17:44 ` Peter Zijlstra
2016-06-16 17:44 ` Peter Zijlstra
2016-06-16 19:18 ` Andreas Schwab
2016-06-16 19:18 ` Andreas Schwab
2016-06-16 19:18 ` Andreas Schwab
2016-06-16 19:18 ` Andreas Schwab
2016-06-16 19:55 ` Geert Uytterhoeven
2016-06-16 19:55 ` Geert Uytterhoeven
2016-06-16 19:55 ` Geert Uytterhoeven
2016-06-16 19:55 ` Geert Uytterhoeven
2016-06-16 14:56 ` Peter Zijlstra
2016-06-16 14:37 ` Andreas Schwab
2016-06-17 15:40 ` Peter Zijlstra
2016-06-17 15:40 ` Peter Zijlstra
2016-06-17 15:40 ` Peter Zijlstra
2016-06-17 15:40 ` Peter Zijlstra
2016-06-20 17:47 ` Andreas Schwab
2016-06-20 17:47 ` Andreas Schwab
2016-06-20 17:47 ` Andreas Schwab
2016-06-20 17:47 ` Andreas Schwab
2016-06-21 4:27 ` Finn Thain
2016-06-21 4:27 ` Finn Thain
2016-06-21 4:27 ` Finn Thain
2016-06-16 12:43 ` Andreas Schwab
2016-06-16 10:13 ` Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 15/33] locking,metag: " Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 16/33] locking,mips: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 17/33] locking,mn10300: Implement atomic_fetch_{add,sub,and,or,xor}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 18/33] locking,parisc: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 19/33] locking,powerpc: Implement atomic{,64}_fetch_{add,sub,and,or,xor}{,_relaxed,_acquire,_release}() Peter Zijlstra
2016-06-01 3:11 ` Boqun Feng
2016-06-01 6:10 ` Boqun Feng
2016-06-01 8:46 ` Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 20/33] locking,s390: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 21/33] locking,sh: Implement atomic_fetch_{add,sub,and,or,xor}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 22/33] locking,sparc: Implement atomic{,64}_fetch_{add,sub,and,or,xor}() Peter Zijlstra
2016-05-31 17:50 ` David Miller
2016-05-31 10:19 ` [PATCH -v2 23/33] locking,tile: " Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 24/33] locking,x86: " Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 25/33] locking,xtensa: Implement atomic_fetch_{add,sub,and,or,xor}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 26/33] locking: Fix atomic64_relaxed bits Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 27/33] locking: Implement atomic{,64,_long}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}() Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 28/33] locking: Remove linux/atomic.h:atomic_fetch_or Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 29/33] locking: Remove the deprecated atomic_{set,clear}_mask() functions Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 30/33] locking,alpha: Convert to _relaxed atomics Peter Zijlstra
2016-05-31 10:19 ` [PATCH -v2 31/33] locking,mips: " Peter Zijlstra
2016-05-31 10:19 ` Peter Zijlstra [this message]
2016-05-31 10:19 ` [PATCH -v2 33/33] locking,rwsem: Employ atomic_long_fetch_add() Peter Zijlstra
2016-06-01 14:06 ` [PATCH -v2 00/33] implement atomic_fetch_$op Will Deacon
2016-06-02 9:27 ` Vineet Gupta
2016-06-02 9:27 ` Vineet Gupta
2016-06-02 9:33 ` Peter Zijlstra
2016-06-02 9:33 ` Peter Zijlstra
2016-06-08 12:43 ` Peter Zijlstra
2016-06-08 12:43 ` Peter Zijlstra
2016-06-08 12:55 ` Ingo Molnar
2016-06-08 12:55 ` Ingo Molnar
2016-06-08 13:32 ` Peter Zijlstra
2016-06-08 13:32 ` Peter Zijlstra
2016-06-08 14:24 ` Vineet Gupta
2016-06-08 14:38 ` Peter Zijlstra
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