linux.git/arch/mips/include/asm/spinlock.h, branch v3.12 Linux kernel source tree MIPS: Remove redundant instructions from arch_spin_{,try}lock. 2013-04-26T15:18:24+00:00 David Daney david.daney@cavium.com 2013-04-25T15:48:53+00:00 3d39019a1655d195a60a86ebf38f9da30bd83d03 We were doing: SRL $r,$?,16 ANDI $r,$r,0xffff The logical right shift by 16 leaves the upper 16 bits clear, so the subsequent masking out of those bits is redundant, and can safely be removed. Signed-off-by: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
We were doing:
   SRL  $r,$?,16
   ANDI $r,$r,0xffff

The logical right shift by 16 leaves the upper 16 bits clear, so the
subsequent masking out of those bits is redundant, and can safely be
removed.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: Remove further use of .subsection 2013-04-11T13:39:52+00:00 Ralf Baechle ralf@linux-mips.org 2013-04-10T22:16:53+00:00 e01961ceea5453ba93c386adf49fff6d1b811e74 7837314d141c661c70bc13c5050694413ecfe14a [MIPS: Get rid of branches to .subsections] removed most uses of .subsection] removed most uses of .subsection in inline assembler code. It left the instances in spinlock.h alone because we knew their use was in fairly small files where .subsection use was fine but of course this was a fragile assumption. LTO breaks this assumption resulting in build errors due to exceeded branch range, so remove further instances of .subsection. The two functions that still use .macro don't currently cause issues however this use is still fragile. Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
7837314d141c661c70bc13c5050694413ecfe14a [MIPS: Get rid of branches to
.subsections] removed most uses of .subsection] removed most uses of
.subsection in inline assembler code.

It left the instances in spinlock.h alone because we knew their use was
in fairly small files where .subsection use was fine but of course this
was a fragile assumption.  LTO breaks this assumption resulting in build
errors due to exceeded branch range, so remove further instances of
.subsection.

The two functions that still use .macro don't currently cause issues
however this use is still fragile.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: Whitespace cleanup. 2013-02-01T09:00:22+00:00 Ralf Baechle ralf@linux-mips.org 2013-01-22T11:59:30+00:00 7034228792cc561e79ff8600f02884bd4c80e287 Having received another series of whitespace patches I decided to do this once and for all rather than dealing with this kind of patches trickling in forever. Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
Having received another series of whitespace patches I decided to do this
once and for all rather than dealing with this kind of patches trickling
in forever.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: Microoptimize arch_{read,write}_lock 2011-03-25T17:45:13+00:00 Ralf Baechle ralf@linux-mips.org 2011-03-25T17:45:13+00:00 756cca61a7faddcafa582d683b46f32280eda948 Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: Optimize spinlocks. 2010-02-27T11:53:42+00:00 David Daney ddaney@caviumnetworks.com 2010-02-04T19:31:49+00:00 500c2e1fdbcc2b273bd4c695a9b8ac8196f61614 The current locking mechanism uses a ll/sc sequence to release a spinlock. This is slower than a wmb() followed by a store to unlock. The branching forward to .subsection 2 on sc failure slows down the contended case. So we get rid of that part too. Since we are now working on naturally aligned u16 values, we can get rid of a masking operation as the LHU already does the right thing. The ANDI are reversed for better scheduling on multi-issue CPUs On a 12 CPU 750MHz Octeon cn5750 this patch improves ipv4 UDP packet forwarding rates from 3.58*10^6 PPS to 3.99*10^6 PPS, or about 11%. Signed-off-by: David Daney <ddaney@caviumnetworks.com> To: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/937/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
The current locking mechanism uses a ll/sc sequence to release a
spinlock.  This is slower than a wmb() followed by a store to unlock.

The branching forward to .subsection 2 on sc failure slows down the
contended case.  So we get rid of that part too.

Since we are now working on naturally aligned u16 values, we can get
rid of a masking operation as the LHU already does the right thing.
The ANDI are reversed for better scheduling on multi-issue CPUs

On a 12 CPU 750MHz Octeon cn5750 this patch improves ipv4 UDP packet
forwarding rates from 3.58*10^6 PPS to 3.99*10^6 PPS, or about 11%.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/937/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: New macro smp_mb__before_llsc. 2010-02-27T11:53:06+00:00 David Daney ddaney@caviumnetworks.com 2010-01-09T01:17:43+00:00 f252ffd50c97dae87b45f1dbad24f71358ccfbd6 Replace some instances of smp_llsc_mb() with a new macro smp_mb__before_llsc(). It is used before ll/sc sequences that are documented as needing write barrier semantics. The default implementation of smp_mb__before_llsc() is just smp_llsc_mb(), so there are no changes in semantics. Also simplify definition of smp_mb(), smp_rmb(), and smp_wmb() to be just barrier() in the non-SMP case. Signed-off-by: David Daney <ddaney@caviumnetworks.com> To: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/851/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
Replace some instances of smp_llsc_mb() with a new macro
smp_mb__before_llsc().  It is used before ll/sc sequences that are
documented as needing write barrier semantics.

The default implementation of smp_mb__before_llsc() is just smp_llsc_mb(),
so there are no changes in semantics.

Also simplify definition of smp_mb(), smp_rmb(), and smp_wmb() to be just
barrier() in the non-SMP case.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/851/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
locking: Convert raw_rwlock functions to arch_rwlock 2009-12-14T22:55:32+00:00 Thomas Gleixner tglx@linutronix.de 2009-12-03T19:08:46+00:00 e5931943d02bf751b1ec849c0d2ade23d76a8d41 Name space cleanup for rwlock functions. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: linux-arch@vger.kernel.org 
Name space cleanup for rwlock functions. No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: linux-arch@vger.kernel.org
locking: Convert raw_rwlock to arch_rwlock 2009-12-14T22:55:32+00:00 Thomas Gleixner tglx@linutronix.de 2009-12-03T19:01:19+00:00 fb3a6bbc912b12347614e5742c7c61416cdb0ca0 Not strictly necessary for -rt as -rt does not have non sleeping rwlocks, but it's odd to not have a consistent naming convention. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: linux-arch@vger.kernel.org 
Not strictly necessary for -rt as -rt does not have non sleeping
rwlocks, but it's odd to not have a consistent naming convention.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: linux-arch@vger.kernel.org
locking: Convert __raw_spin* functions to arch_spin* 2009-12-14T22:55:32+00:00 Thomas Gleixner tglx@linutronix.de 2009-12-02T19:01:25+00:00 0199c4e68d1f02894bdefe4b5d9e9ee4aedd8d62 Name space cleanup. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: linux-arch@vger.kernel.org 
Name space cleanup. No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: linux-arch@vger.kernel.org
locking: Convert raw_spinlock to arch_spinlock 2009-12-14T22:55:32+00:00 Thomas Gleixner tglx@linutronix.de 2009-12-02T18:49:50+00:00 445c89514be242b1b0080056d50bdc1b72adeb5c The raw_spin* namespace was taken by lockdep for the architecture specific implementations. raw_spin_* would be the ideal name space for the spinlocks which are not converted to sleeping locks in preempt-rt. Linus suggested to convert the raw_ to arch_ locks and cleanup the name space instead of using an artifical name like core_spin, atomic_spin or whatever No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: linux-arch@vger.kernel.org 
The raw_spin* namespace was taken by lockdep for the architecture
specific implementations. raw_spin_* would be the ideal name space for
the spinlocks which are not converted to sleeping locks in preempt-rt.

Linus suggested to convert the raw_ to arch_ locks and cleanup the
name space instead of using an artifical name like core_spin,
atomic_spin or whatever

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: linux-arch@vger.kernel.org