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alpha/mm/fault.c: Port OOM changes to do_page_fault 

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

Signed-off-by: Mohd. Faris <mohdfarisq2010@gmail.com>
Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Acked-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Michael Cree <mcree@orcon.net.nz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kautuk Consul 2012-08-19 14:41:01 +12:00 committed by Linus Torvalds
parent 28d353d989
commit 0bcc426b1d
1 changed files with 30 additions and 6 deletions
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36
arch/alpha/mm/fault.c
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@ -89,6 +89,8 @@ do_page_fault(unsigned long address, unsigned long mmcsr,
const struct exception_table_entry *fixup;
int fault, si_code = SEGV_MAPERR;
siginfo_t info;
unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
(cause > 0 ? FAULT_FLAG_WRITE : 0));
/* As of EV6, a load into $31/$f31 is a prefetch, and never faults
(or is suppressed by the PALcode). Support that for older CPUs
@ -114,6 +116,7 @@ do_page_fault(unsigned long address, unsigned long mmcsr,
goto vmalloc_fault;
#endif
retry:
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
if (!vma)
@ -144,8 +147,11 @@ do_page_fault(unsigned long address, unsigned long mmcsr,
/* 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, address, cause > 0 ? FAULT_FLAG_WRITE : 0);
up_read(&mm->mmap_sem);
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;
@ -153,10 +159,26 @@ do_page_fault(unsigned long address, unsigned long mmcsr,
goto do_sigbus;
BUG();
}
if (fault & VM_FAULT_MAJOR)
current->maj_flt++;
else
current->min_flt++;
if (flags & FAULT_FLAG_ALLOW_RETRY) {
if (fault & VM_FAULT_MAJOR)
current->maj_flt++;
else
current->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;
}
}
up_read(&mm->mmap_sem);
return;
/* Something tried to access memory that isn't in our memory map.
@ -186,12 +208,14 @@ do_page_fault(unsigned long address, unsigned long mmcsr,
/* We ran out of memory, or some other thing happened to us that
made us unable to handle the page fault gracefully. */
out_of_memory:
up_read(&mm->mmap_sem);
if (!user_mode(regs))
goto no_context;
pagefault_out_of_memory();
return;
do_sigbus:
up_read(&mm->mmap_sem);
/* Send a sigbus, regardless of whether we were in kernel
or user mode. */
info.si_signo = SIGBUS;