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xtensa/mm/fault.c: port OOM changes to do_page_fault 

Commits 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 xtensa.

Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Acked-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kautuk Consul 2012-07-30 14:39:21 -07:00 committed by Linus Torvalds
parent 54b501992d
commit f107701f01
1 changed files with 24 additions and 5 deletions
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29
arch/xtensa/mm/fault.c
View File

@ -44,6 +44,7 @@ void do_page_fault(struct pt_regs *regs)
int is_write, is_exec;
int fault;
unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
info.si_code = SEGV_MAPERR;
@ -71,6 +72,7 @@ void do_page_fault(struct pt_regs *regs)
address, exccause, regs->pc, is_write? "w":"", is_exec? "x":"");
#endif
retry:
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
@ -93,6 +95,7 @@ good_area:
if (is_write) {
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
flags |= FAULT_FLAG_WRITE;
} else if (is_exec) {
if (!(vma->vm_flags & VM_EXEC))
goto bad_area;
@ -104,7 +107,11 @@ good_area:
* make sure we exit gracefully rather than endlessly redo
* the fault.
*/
fault = handle_mm_fault(mm, vma, address, is_write ? 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;
@ -112,10 +119,22 @@ good_area:
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;