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x86: Move do_page_fault()'s error path under unlikely()

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Ingo suggested SIGKILL check should be moved into slowpath
function. This will reduce the page fault fastpath impact
of this recent commit:

  37b23e0525d3: x86,mm: make pagefault killable

Suggested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: kamezawa.hiroyu@jp.fujitsu.com
Cc: minchan.kim@gmail.com
Cc: willy@linux.intel.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/4DDE0B5C.9050907@jp.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
KOSAKI Motohiro 2011-05-26 17:12:12 +09:00 committed by Ingo Molnar
parent de66ee979d
commit b80ef10e84
1 changed files with 20 additions and 15 deletions
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35
arch/x86/mm/fault.c
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@ -823,16 +823,30 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
force_sig_info_fault(SIGBUS, code, address, tsk, fault); force_sig_info_fault(SIGBUS, code, address, tsk, fault);
} }
static noinline void static noinline int
mm_fault_error(struct pt_regs *regs, unsigned long error_code, mm_fault_error(struct pt_regs *regs, unsigned long error_code,
unsigned long address, unsigned int fault) unsigned long address, unsigned int fault)
{ {
/*
* Pagefault was interrupted by SIGKILL. We have no reason to
* continue pagefault.
*/
if (fatal_signal_pending(current)) {
if (!(fault & VM_FAULT_RETRY))
up_read(&current->mm->mmap_sem);
if (!(error_code & PF_USER))
no_context(regs, error_code, address);
return 1;
}
if (!(fault & VM_FAULT_ERROR))
return 0;
if (fault & VM_FAULT_OOM) { if (fault & VM_FAULT_OOM) {
/* Kernel mode? Handle exceptions or die: */ /* Kernel mode? Handle exceptions or die: */
if (!(error_code & PF_USER)) { if (!(error_code & PF_USER)) {
up_read(&current->mm->mmap_sem); up_read(&current->mm->mmap_sem);
no_context(regs, error_code, address); no_context(regs, error_code, address);
return; return 1;
} }
out_of_memory(regs, error_code, address); out_of_memory(regs, error_code, address);
@ -843,6 +857,7 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
else else
BUG(); BUG();
} }
return 1;
} }
static int spurious_fault_check(unsigned long error_code, pte_t *pte) static int spurious_fault_check(unsigned long error_code, pte_t *pte)
@ -1133,19 +1148,9 @@ good_area:
*/ */
fault = handle_mm_fault(mm, vma, address, flags); fault = handle_mm_fault(mm, vma, address, flags);
if (unlikely(fault & VM_FAULT_ERROR)) { if (unlikely(fault & (VM_FAULT_RETRY|VM_FAULT_ERROR))) {
mm_fault_error(regs, error_code, address, fault); if (mm_fault_error(regs, error_code, address, fault))
return; return;
}
/*
* Pagefault was interrupted by SIGKILL. We have no reason to
* continue pagefault.
*/
if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) {
if (!(error_code & PF_USER))
no_context(regs, error_code, address);
return;
} }
/* /*