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tile/mm/fault.c: Port OOM changes to handle_page_fault 

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 tile.

Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
[cmetcalf@tilera.com: initialize "flags" after "write" updated.]
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
This commit is contained in:
Kautuk Consul 2012-03-31 08:05:39 -04:00 committed by Chris Metcalf
parent c6f696f69a
commit 4ce6bea220
1 changed files with 27 additions and 5 deletions
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32
arch/tile/mm/fault.c
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@ -273,11 +273,15 @@ static int handle_page_fault(struct pt_regs *regs,
int si_code;
int is_kernel_mode;
pgd_t *pgd;
unsigned int flags;
/* on TILE, protection faults are always writes */
if (!is_page_fault)
write = 1;
flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
(write ? FAULT_FLAG_WRITE : 0));
is_kernel_mode = (EX1_PL(regs->ex1) != USER_PL);
tsk = validate_current();
@ -382,6 +386,8 @@ static int handle_page_fault(struct pt_regs *regs,
vma = NULL; /* happy compiler */
goto bad_area_nosemaphore;
}
retry:
down_read(&mm->mmap_sem);
}
@ -429,7 +435,11 @@ good_area:
* make sure we exit gracefully rather than endlessly redo
* the fault.
*/
fault = handle_mm_fault(mm, vma, address, write);
fault = handle_mm_fault(mm, vma, address, flags);
if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
return 0;
if (unlikely(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_OOM)
goto out_of_memory;
@ -437,10 +447,22 @@ good_area:
goto do_sigbus;
BUG();
}
if (fault & VM_FAULT_MAJOR)
tsk->maj_flt++;
else
tsk->min_flt++;
if (flags & FAULT_FLAG_ALLOW_RETRY) {
if (fault & VM_FAULT_MAJOR)
tsk->maj_flt++;
else
tsk->min_flt++;
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;
}
}
#if CHIP_HAS_TILE_DMA() || CHIP_HAS_SN_PROC()
/*