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sh/mm/fault_32.c: Port OOM changes to do_page_fault

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Commit d065bd810b
(mm: retry page fault when blocking on disk transfer) and
commit 37b23e0525
(x86,mm: make pagefault killable)

The above commits introduced changes into the x86 pagefault handler
for making the page fault handler retryable as well as killable.

These changes reduce the mmap_sem hold time, which is crucial
during OOM killer invocation.

Port these changes to the 32-bit SH platform.

Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Kautuk Consul 2012-03-31 08:06:11 -04:00 committed by Paul Mundt
parent bbb4ce50f3
commit 11fd982400
1 changed files with 29 additions and 9 deletions
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38
arch/sh/mm/fault_32.c
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@ -129,6 +129,8 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
int si_code;
int fault;
siginfo_t info;
unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
(writeaccess ? FAULT_FLAG_WRITE : 0));
tsk = current;
mm = tsk->mm;
@ -169,6 +171,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
if (in_atomic() || !mm)
goto no_context;
retry:
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
@ -200,7 +203,11 @@ good_area:
* make sure we exit gracefully rather than endlessly redo
* the fault.
*/
fault = handle_mm_fault(mm, vma, address, writeaccess ? FAULT_FLAG_WRITE : 0);
fault = handle_mm_fault(mm, vma, address, flags);
if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
return;
if (unlikely(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_OOM)
goto out_of_memory;
@ -208,14 +215,27 @@ good_area:
goto do_sigbus;
BUG();
}
if (fault & VM_FAULT_MAJOR) {
tsk->maj_flt++;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
regs, address);
} else {
tsk->min_flt++;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
regs, address);
if (flags & FAULT_FLAG_ALLOW_RETRY) {
if (fault & VM_FAULT_MAJOR) {
tsk->maj_flt++;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
regs, address);
} else {
tsk->min_flt++;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
regs, address);
}
if (fault & VM_FAULT_RETRY) {
flags &= ~FAULT_FLAG_ALLOW_RETRY;
/*
* No need to up_read(&mm->mmap_sem) as we would
* have already released it in __lock_page_or_retry
* in mm/filemap.c.
*/
goto retry;
}
}
up_read(&mm->mmap_sem);