Messages in this thread Patch in this message | | | From | Kautuk Consul <> | Subject | [PATCH 08/19 v2] m32r/mm/fault.c: Port OOM changes to do_page_fault | Date | Sat, 31 Mar 2012 08:03:05 -0400 |
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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 m32r.
Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> --- arch/m32r/mm/fault.c | 32 +++++++++++++++++++++++++++----- 1 files changed, 27 insertions(+), 5 deletions(-)
diff --git a/arch/m32r/mm/fault.c b/arch/m32r/mm/fault.c index 3cdfa9c..d0e08e2 100644 --- a/arch/m32r/mm/fault.c +++ b/arch/m32r/mm/fault.c @@ -81,6 +81,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code, int write; int fault; siginfo_t info; + unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; /* * If BPSW IE bit enable --> set PSW IE bit @@ -136,6 +137,8 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code, if ((error_code & ACE_USERMODE) == 0 && !search_exception_tables(regs->psw)) goto bad_area_nosemaphore; + +retry: down_read(&mm->mmap_sem); } @@ -174,6 +177,7 @@ good_area: if (!(vma->vm_flags & VM_WRITE)) goto bad_area; write++; + flags |= FAULT_FLAG_WRITE; break; case ACE_PROTECTION: /* read, present */ case 0: /* read, not present */ @@ -194,7 +198,11 @@ good_area: */ addr = (address & PAGE_MASK); set_thread_fault_code(error_code); - fault = handle_mm_fault(mm, vma, addr, write ? FAULT_FLAG_WRITE : 0); + fault = handle_mm_fault(mm, vma, addr, 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; @@ -202,10 +210,24 @@ good_area: goto do_sigbus; BUG(); } - if (fault & VM_FAULT_MAJOR) - tsk->maj_flt++; - else - tsk->min_flt++; + + if (flags & FAULT_FLAG_ALLOW_RETRY) { + if (fault & VM_FAULT_MAJOR) + tsk->maj_flt++; + else + tsk->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; + } + } + set_thread_fault_code(0); up_read(&mm->mmap_sem); return; -- 1.7.5.4
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