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authorKautuk Consul <consul.kautuk@gmail.com>2012-03-31 08:05:17 -0400
committerGuan Xuetao <gxt@mprc.pku.edu.cn>2012-11-09 17:30:08 +0800
commitf3f09d5a4462929609342460d756fab2e8151421 (patch)
tree43ce4d51ebca8aaca25514ca57e9b61e764ff51b /arch/unicore32
parent0e4a43ed08e2f44aa7b96aa95d0a540d675483e1 (diff)
downloadvexpress-lsk-f3f09d5a4462929609342460d756fab2e8151421.tar.gz
unicore32/mm/fault.c: Port OOM changes to do_pf
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 unicore32. Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Diffstat (limited to 'arch/unicore32')
-rw-r--r--arch/unicore32/mm/fault.c37
1 files changed, 27 insertions, 10 deletions
diff --git a/arch/unicore32/mm/fault.c b/arch/unicore32/mm/fault.c
index 2eeb9c04cab..f9b5c10bcce 100644
--- a/arch/unicore32/mm/fault.c
+++ b/arch/unicore32/mm/fault.c
@@ -168,7 +168,7 @@ static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
}
static int __do_pf(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
- struct task_struct *tsk)
+ unsigned int flags, struct task_struct *tsk)
{
struct vm_area_struct *vma;
int fault;
@@ -194,14 +194,7 @@ good_area:
* If for any reason at all we couldn't handle the fault, make
* sure we exit gracefully rather than endlessly redo the fault.
*/
- fault = handle_mm_fault(mm, vma, addr & PAGE_MASK,
- (!(fsr ^ 0x12)) ? FAULT_FLAG_WRITE : 0);
- if (unlikely(fault & VM_FAULT_ERROR))
- return fault;
- if (fault & VM_FAULT_MAJOR)
- tsk->maj_flt++;
- else
- tsk->min_flt++;
+ fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, flags);
return fault;
check_stack:
@@ -216,6 +209,8 @@ static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
struct task_struct *tsk;
struct mm_struct *mm;
int fault, sig, code;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
+ ((!(fsr ^ 0x12)) ? FAULT_FLAG_WRITE : 0);
tsk = current;
mm = tsk->mm;
@@ -236,6 +231,7 @@ static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
if (!user_mode(regs)
&& !search_exception_tables(regs->UCreg_pc))
goto no_context;
+retry:
down_read(&mm->mmap_sem);
} else {
/*
@@ -251,7 +247,28 @@ static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
#endif
}
- fault = __do_pf(mm, addr, fsr, tsk);
+ fault = __do_pf(mm, addr, fsr, flags, tsk);
+
+ /* If we need to retry but a fatal signal is pending, handle the
+ * signal first. We do not need to release the mmap_sem because
+ * it would already be released in __lock_page_or_retry in
+ * mm/filemap.c. */
+ if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+ return 0;
+
+ if (!(fault & VM_FAULT_ERROR) && (flags & FAULT_FLAG_ALLOW_RETRY)) {
+ if (fault & VM_FAULT_MAJOR)
+ tsk->maj_flt++;
+ else
+ tsk->min_flt++;
+ if (fault & VM_FAULT_RETRY) {
+ /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
+ * of starvation. */
+ flags &= ~FAULT_FLAG_ALLOW_RETRY;
+ goto retry;
+ }
+ }
+
up_read(&mm->mmap_sem);
/*