diff options
| author | Kautuk Consul <consul.kautuk@gmail.com> | 2012-03-25 06:37:48 -0400 |
|---|---|---|
| committer | Geert Uytterhoeven <geert@linux-m68k.org> | 2012-04-22 20:16:49 +0200 |
| commit | b637a6b16731d806ae2c8b9619a5619a2f283f15 (patch) | |
| tree | 1f7f86a392b36b6dfb160449736a8a43647e84c4 /arch/m68k/mm | |
| parent | 107b5d5302b184b72a2f12d9d23f2fcd4ce8a6ec (diff) | |
m68k/mm: 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 m68k.
Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Diffstat (limited to 'arch/m68k/mm')
| -rw-r--r-- | arch/m68k/mm/fault.c | 42 |
1 files changed, 34 insertions, 8 deletions
diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c index 6b020a8461e7..aeebbb7b30f0 100644 --- a/arch/m68k/mm/fault.c +++ b/arch/m68k/mm/fault.c @@ -72,7 +72,8 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, { struct mm_struct *mm = current->mm; struct vm_area_struct * vma; - int write, fault; + int fault; + unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; #ifdef DEBUG printk ("do page fault:\nregs->sr=%#x, regs->pc=%#lx, address=%#lx, %ld, %p\n", @@ -87,6 +88,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, if (in_atomic() || !mm) goto no_context; +retry: down_read(&mm->mmap_sem); vma = find_vma(mm, address); @@ -117,14 +119,13 @@ good_area: #ifdef DEBUG printk("do_page_fault: good_area\n"); #endif - write = 0; switch (error_code & 3) { default: /* 3: write, present */ /* fall through */ case 2: /* write, not present */ if (!(vma->vm_flags & VM_WRITE)) goto acc_err; - write++; + flags |= FAULT_FLAG_WRITE; break; case 1: /* read, present */ goto acc_err; @@ -139,10 +140,14 @@ good_area: * the fault. */ - fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0); + fault = handle_mm_fault(mm, vma, address, flags); #ifdef DEBUG printk("handle_mm_fault returns %d\n",fault); #endif + + if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + return 0; + if (unlikely(fault & VM_FAULT_ERROR)) { if (fault & VM_FAULT_OOM) goto out_of_memory; @@ -150,10 +155,31 @@ good_area: goto bus_err; BUG(); } - if (fault & VM_FAULT_MAJOR) - current->maj_flt++; - else - current->min_flt++; + + /* + * Major/minor page fault accounting is only done on the + * initial attempt. If we go through a retry, it is extremely + * likely that the page will be found in page cache at that point. + */ + if (flags & FAULT_FLAG_ALLOW_RETRY) { + if (fault & VM_FAULT_MAJOR) + current->maj_flt++; + else + current->min_flt++; + if (fault & VM_FAULT_RETRY) { + /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk + * of starvation. */ + 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 0; |