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authorKautuk Consul <consul.kautuk@gmail.com>2012-05-31 16:26:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-31 17:49:26 -0700
commit1cefe28f95da307287a05a6a0c10213f01055e2a (patch)
tree6810a5c8f413f67d359da6243ee75c60c704d16c /arch
parent4f1c28d241d0882f25112d494885cd6084db225b (diff)
downloadlinux-1cefe28f95da307287a05a6a0c10213f01055e2a.tar.gz
um/kernel/trap.c: port OOM changes to handle_page_fault()
Commit d065bd810b6d ("mm: retry page fault when blocking on disk transfer") and commit 37b23e0525d3 ("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 um. Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/um/kernel/trap.c24
1 files changed, 19 insertions, 5 deletions
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index dafc9471595..3be60765c0e 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -30,6 +30,8 @@ int handle_page_fault(unsigned long address, unsigned long ip,
pmd_t *pmd;
pte_t *pte;
int err = -EFAULT;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
+ (is_write ? FAULT_FLAG_WRITE : 0);
*code_out = SEGV_MAPERR;
@@ -40,6 +42,7 @@ int handle_page_fault(unsigned long address, unsigned long ip,
if (in_atomic())
goto out_nosemaphore;
+retry:
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
if (!vma)
@@ -65,7 +68,11 @@ good_area:
do {
int 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))
+ goto out_nosemaphore;
+
if (unlikely(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_OOM) {
goto out_of_memory;
@@ -75,10 +82,17 @@ good_area:
}
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;
+
+ goto retry;
+ }
+ }
pgd = pgd_offset(mm, address);
pud = pud_offset(pgd, address);