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unicore32/mm/fault.c: Port OOM changes to do_pf

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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 unicore32.

Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
This commit is contained in:
Kautuk Consul 2012-03-31 08:05:17 -04:00 committed by Guan Xuetao
parent 0e4a43ed08
commit f3f09d5a44
1 changed files with 27 additions and 10 deletions
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37
arch/unicore32/mm/fault.c
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@ -168,7 +168,7 @@ static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
}
static int __do_pf(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
struct task_struct *tsk)
unsigned int flags, struct task_struct *tsk)
{
struct vm_area_struct *vma;
int fault;
@ -194,14 +194,7 @@ good_area:
* If for any reason at all we couldn't handle the fault, make
* sure we exit gracefully rather than endlessly redo the fault.
*/
fault = handle_mm_fault(mm, vma, addr & PAGE_MASK,
(!(fsr ^ 0x12)) ? FAULT_FLAG_WRITE : 0);
if (unlikely(fault & VM_FAULT_ERROR))
return fault;
if (fault & VM_FAULT_MAJOR)
tsk->maj_flt++;
else
tsk->min_flt++;
fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, flags);
return fault;
check_stack:
@ -216,6 +209,8 @@ static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
struct task_struct *tsk;
struct mm_struct *mm;
int fault, sig, code;
unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
((!(fsr ^ 0x12)) ? FAULT_FLAG_WRITE : 0);
tsk = current;
mm = tsk->mm;
@ -236,6 +231,7 @@ static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
if (!user_mode(regs)
&& !search_exception_tables(regs->UCreg_pc))
goto no_context;
retry:
down_read(&mm->mmap_sem);
} else {
/*
@ -251,7 +247,28 @@ static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
#endif
}
fault = __do_pf(mm, addr, fsr, tsk);
fault = __do_pf(mm, addr, fsr, flags, tsk);
/* If we need to retry but a fatal signal is pending, handle the
* signal first. We do not need to release the mmap_sem because
* it would already be released in __lock_page_or_retry in
* mm/filemap.c. */
if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
return 0;
if (!(fault & VM_FAULT_ERROR) && (flags & FAULT_FLAG_ALLOW_RETRY)) {
if (fault & VM_FAULT_MAJOR)
tsk->maj_flt++;
else
tsk->min_flt++;
if (fault & VM_FAULT_RETRY) {
/* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
* of starvation. */
flags &= ~FAULT_FLAG_ALLOW_RETRY;
goto retry;
}
}
up_read(&mm->mmap_sem);
/*