linux/arch
Thomas Gleixner 8b0b1db013 remove put_cpu_no_resched()
put_cpu_no_resched() is an optimization of put_cpu() which unfortunately
can cause high latencies.

The nfs iostats code uses put_cpu_no_resched() in a code sequence where a
reschedule request caused by an interrupt between the get_cpu() and the
put_cpu_no_resched() can delay the reschedule for at least HZ.

The other users of put_cpu_no_resched() optimize correctly in interrupt
code, but there is no real harm in using the put_cpu() function which is
an alias for preempt_enable().  The extra check of the preemmpt count is
not as critical as the potential source of missing a reschedule.

Debugged in the preempt-rt tree and verified in mainline.

Impact: remove a high latency source

[akpm@linux-foundation.org: build fix]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16 19:47:48 -07:00
..
alpha alpha: bad macro expansion, parameter is member 2009-06-16 19:47:46 -07:00
arm mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
avr32 mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
blackfin mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
cris mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
frv mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
h8300 mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
ia64 remove put_cpu_no_resched() 2009-06-16 19:47:48 -07:00
m32r m32r: remove obsolete hw_interrupt_type 2009-06-16 19:47:46 -07:00
m68k mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
m68knommu mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
microblaze Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic 2009-06-12 18:15:51 -07:00
mips mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
mn10300 mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
parisc mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
powerpc page allocator: do not check NUMA node ID when the caller knows the node is valid 2009-06-16 19:47:32 -07:00
s390 mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
sh mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
sparc mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
um uml: bad macro expansion, parameter is member 2009-06-16 19:47:47 -07:00
x86 page allocator: do not check NUMA node ID when the caller knows the node is valid 2009-06-16 19:47:32 -07:00
xtensa mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
.gitignore
Kconfig mutex: have non-spinning mutexes on s390 by default 2009-04-09 19:28:24 +02:00