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authorLinus Torvalds <torvalds@linux-foundation.org>2013-07-03 01:19:24 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-03 01:19:24 +0200
commite13053f50664d3d614bbc9b8c83abdad979ac7c9 (patch)
tree07ee41cd50ba26bd7ec92255184f80aff70a2e9a /arch/mn10300
parentMerge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/ker... (diff)
parentmm, sched: Allow uaccess in atomic with pagefault_disable() (diff)
downloadlinux-e13053f50664d3d614bbc9b8c83abdad979ac7c9.tar.xz
linux-e13053f50664d3d614bbc9b8c83abdad979ac7c9.zip
Merge branch 'sched-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull voluntary preemption fixes from Ingo Molnar: "This tree contains a speedup which is achieved through better might_sleep()/might_fault() preemption point annotations for uaccess functions, by Michael S Tsirkin: 1. The only reason uaccess routines might sleep is if they fault. Make this explicit for all architectures. 2. A voluntary preemption point in uaccess functions means compiler can't inline them efficiently, this breaks assumptions that they are very fast and small that e.g. net code seems to make. Remove this preemption point so behaviour matches with what callers assume. 3. Accesses (e.g through socket ops) to kernel memory with KERNEL_DS like net/sunrpc does will never sleep. Remove an unconditinal might_sleep() in the might_fault() inline in kernel.h (used when PROVE_LOCKING is not set). 4. Accesses with pagefault_disable() return EFAULT but won't cause caller to sleep. Check for that and thus avoid might_sleep() when PROVE_LOCKING is set. These changes offer a nice speedup for CONFIG_PREEMPT_VOLUNTARY=y kernels, here's a network bandwidth measurement between a virtual machine and the host: before: incoming: 7122.77 Mb/s outgoing: 8480.37 Mb/s after: incoming: 8619.24 Mb/s [ +21.0% ] outgoing: 9455.42 Mb/s [ +11.5% ] I kept these changes in a separate tree, separate from scheduler changes, because it's a mixed MM and scheduler topic" * 'sched-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: mm, sched: Allow uaccess in atomic with pagefault_disable() mm, sched: Drop voluntary schedule from might_fault() x86: uaccess s/might_sleep/might_fault/ tile: uaccess s/might_sleep/might_fault/ powerpc: uaccess s/might_sleep/might_fault/ mn10300: uaccess s/might_sleep/might_fault/ microblaze: uaccess s/might_sleep/might_fault/ m32r: uaccess s/might_sleep/might_fault/ frv: uaccess s/might_sleep/might_fault/ arm64: uaccess s/might_sleep/might_fault/ asm-generic: uaccess s/might_sleep/might_fault/
Diffstat (limited to 'arch/mn10300')
-rw-r--r--arch/mn10300/include/asm/uaccess.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/mn10300/include/asm/uaccess.h b/arch/mn10300/include/asm/uaccess.h
index d7966e0f7698..537278746a15 100644
--- a/arch/mn10300/include/asm/uaccess.h
+++ b/arch/mn10300/include/asm/uaccess.h
@@ -471,13 +471,13 @@ extern unsigned long __generic_copy_from_user(void *, const void __user *,
#define __copy_to_user(to, from, n) \
({ \
- might_sleep(); \
+ might_fault(); \
__copy_to_user_inatomic((to), (from), (n)); \
})
#define __copy_from_user(to, from, n) \
({ \
- might_sleep(); \
+ might_fault(); \
__copy_from_user_inatomic((to), (from), (n)); \
})