diff options
| author | Kautuk Consul <consul.kautuk@gmail.com> | 2012-08-19 14:41:01 +1200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-08-19 08:41:19 -0700 |
| commit | 0bcc426b1defa6b629dfa722537cab38876a3ce4 (patch) | |
| tree | e545cca77bcafdf9071e0eb7647051e391f4436b | |
| parent | 28d353d9891c28496e366bebe4e65233f59ad1f6 (diff) | |
alpha/mm/fault.c: Port OOM changes to do_page_fault
Commit d065bd810b6d ("mm: retry page fault when blocking on disk
transfer") and 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 ALPHA.
Signed-off-by: Mohd. Faris <mohdfarisq2010@gmail.com>
Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Acked-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Michael Cree <mcree@orcon.net.nz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | arch/alpha/mm/fault.c | 36 |
1 files changed, 30 insertions, 6 deletions
diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c index 5eecab1a84ef..0c4132dd3507 100644 --- a/arch/alpha/mm/fault.c +++ b/arch/alpha/mm/fault.c @@ -89,6 +89,8 @@ do_page_fault(unsigned long address, unsigned long mmcsr, const struct exception_table_entry *fixup; int fault, si_code = SEGV_MAPERR; siginfo_t info; + unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE | + (cause > 0 ? FAULT_FLAG_WRITE : 0)); /* As of EV6, a load into $31/$f31 is a prefetch, and never faults (or is suppressed by the PALcode). Support that for older CPUs @@ -114,6 +116,7 @@ do_page_fault(unsigned long address, unsigned long mmcsr, goto vmalloc_fault; #endif +retry: down_read(&mm->mmap_sem); vma = find_vma(mm, address); if (!vma) @@ -144,8 +147,11 @@ do_page_fault(unsigned long address, unsigned long mmcsr, /* 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, address, cause > 0 ? FAULT_FLAG_WRITE : 0); - up_read(&mm->mmap_sem); + 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; @@ -153,10 +159,26 @@ do_page_fault(unsigned long address, unsigned long mmcsr, goto do_sigbus; 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; /* Something tried to access memory that isn't in our memory map. @@ -186,12 +208,14 @@ do_page_fault(unsigned long address, unsigned long mmcsr, /* We ran out of memory, or some other thing happened to us that made us unable to handle the page fault gracefully. */ out_of_memory: + up_read(&mm->mmap_sem); if (!user_mode(regs)) goto no_context; pagefault_out_of_memory(); return; do_sigbus: + up_read(&mm->mmap_sem); /* Send a sigbus, regardless of whether we were in kernel or user mode. */ info.si_signo = SIGBUS; |