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authorKautuk Consul <consul.kautuk@gmail.com>2012-06-14 13:11:37 -0700
committerTony Luck <tony.luck@intel.com>2012-06-14 13:11:37 -0700
commitf28fa729149c8b39699f7995ce5fff34c5145a9d (patch)
tree3dba7e7ef8b5eb76d456a0172706ec2162ef13d9
parentcfaf025112d3856637ff34a767ef785ef5cf2ca9 (diff)
downloadop-kernel-dev-f28fa729149c8b39699f7995ce5fff34c5145a9d.zip
op-kernel-dev-f28fa729149c8b39699f7995ce5fff34c5145a9d.tar.gz
[IA64] Port OOM changes to ia64_do_page_fault
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@gmail.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
-rw-r--r--arch/ia64/mm/fault.c46
1 files changed, 34 insertions, 12 deletions
diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
index 02d29c2..8443daf 100644
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -72,6 +72,10 @@ mapped_kernel_page_is_present (unsigned long address)
return pte_present(pte);
}
+# define VM_READ_BIT 0
+# define VM_WRITE_BIT 1
+# define VM_EXEC_BIT 2
+
void __kprobes
ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *regs)
{
@@ -81,6 +85,12 @@ 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 +119,7 @@ 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);
@@ -130,10 +141,6 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
/* OK, we've got a good vm_area for this memory area. Check the access permissions: */
-# define VM_READ_BIT 0
-# define VM_WRITE_BIT 1
-# define VM_EXEC_BIT 2
-
# if (((1 << VM_READ_BIT) != VM_READ || (1 << VM_WRITE_BIT) != VM_WRITE) \
|| (1 << VM_EXEC_BIT) != VM_EXEC)
# error File is out of sync with <linux/mm.h>. Please update.
@@ -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;
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