Commit d065bd810b6deb67d4897a14bfe21f8eb526ba99
(mm: retry page fault when blocking on disk transfer) and
commit 37b23e0525d393d48a7d59f870b3bc061a30ccdb
(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 ia64.
Signed-off-by: Kautuk Consul <consul.kautuk@xxxxxxxxx>
---
arch/ia64/mm/fault.c | 38 ++++++++++++++++++++++++++++++--------
1 files changed, 30 insertions(+), 8 deletions(-)
diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
index 02d29c2..b0c3b29 100644
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -81,6 +81,12 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
struct siginfo si;
unsigned long mask;
int fault;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+
+ mask = ((((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT)
+ | (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT));
+
+ flags |= ((mask & VM_WRITE) ? FAULT_FLAG_WRITE : 0);
/* mmap_sem is performance critical.... */
prefetchw(&mm->mmap_sem);
@@ -109,6 +115,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
if (notify_page_fault(regs, TRAP_BRKPT))
return;
+retry:
down_read(&mm->mmap_sem);
vma = find_vma_prev(mm, address, &prev_vma);
@@ -142,9 +149,6 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
if (((isr >> IA64_ISR_R_BIT) & 1UL) && (!(vma->vm_flags & (VM_READ | VM_WRITE))))
goto bad_area;
- mask = ( (((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT)
- | (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT));
-
if ((vma->vm_flags & mask) != mask)
goto bad_area;
@@ -153,7 +157,11 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
* sure we exit gracefully rather than endlessly redo the
* fault.
*/
- fault = handle_mm_fault(mm, vma, address, (mask & VM_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)) {
/*
* We ran out of memory, or some other thing happened
@@ -168,10 +176,24 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
}
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;
--
1.7.5.4
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