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authorKautuk Consul <consul.kautuk@gmail.com>2012-03-20 09:21:40 -0400
committerMichal Simek <monstr@monstr.eu>2012-05-25 06:34:34 +0200
commitf397c077e114df07bd2b94a16681a04be8d59dff (patch)
tree2bf5882aa6cc8a9f1e03b792849a1dc6e2216500 /arch/microblaze
parent59516b07b4ffa7e607a5787674ea3c405f1b390c (diff)
downloadlinux-linaro-stable-f397c077e114df07bd2b94a16681a04be8d59dff.tar.gz
microblaze: Port OOM changes to 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 microblaze. Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Diffstat (limited to 'arch/microblaze')
-rw-r--r--arch/microblaze/mm/fault.c33
1 files changed, 28 insertions, 5 deletions
diff --git a/arch/microblaze/mm/fault.c b/arch/microblaze/mm/fault.c
index c38a265846de..eb365d6795fa 100644
--- a/arch/microblaze/mm/fault.c
+++ b/arch/microblaze/mm/fault.c
@@ -92,6 +92,8 @@ void do_page_fault(struct pt_regs *regs, unsigned long address,
int code = SEGV_MAPERR;
int is_write = error_code & ESR_S;
int fault;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
+ (is_write ? FAULT_FLAG_WRITE : 0);
regs->ear = address;
regs->esr = error_code;
@@ -138,6 +140,7 @@ void do_page_fault(struct pt_regs *regs, unsigned long address,
if (kernel_mode(regs) && !search_exception_tables(regs->pc))
goto bad_area_nosemaphore;
+retry:
down_read(&mm->mmap_sem);
}
@@ -210,7 +213,11 @@ 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;
@@ -218,11 +225,27 @@ good_area:
goto do_sigbus;
BUG();
}
- if (unlikely(fault & VM_FAULT_MAJOR))
- current->maj_flt++;
- else
- current->min_flt++;
+
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (unlikely(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);
+
/*
* keep track of tlb+htab misses that are good addrs but
* just need pte's created via handle_mm_fault()