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| author | Kautuk Consul <consul.kautuk@gmail.com> | 2012-06-01 01:26:03 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-06-01 02:49:26 +0200 |
| commit | 1cefe28f95da307287a05a6a0c10213f01055e2a (patch) | |
| tree | 6810a5c8f413f67d359da6243ee75c60c704d16c /arch/um/kernel | |
| parent | security/keys/keyctl.c: suppress memory allocation failure warning (diff) | |
| download | linux-1cefe28f95da307287a05a6a0c10213f01055e2a.tar.xz linux-1cefe28f95da307287a05a6a0c10213f01055e2a.zip | |
um/kernel/trap.c: port OOM changes to handle_page_fault()
Commit d065bd810b6d ("mm: retry page fault when blocking on disk
transfer") and commit 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 um.
Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/um/kernel')
| -rw-r--r-- | arch/um/kernel/trap.c | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c index dafc94715950..3be60765c0e2 100644 --- a/arch/um/kernel/trap.c +++ b/arch/um/kernel/trap.c @@ -30,6 +30,8 @@ int handle_page_fault(unsigned long address, unsigned long ip, pmd_t *pmd; pte_t *pte; int err = -EFAULT; + unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE | + (is_write ? FAULT_FLAG_WRITE : 0); *code_out = SEGV_MAPERR; @@ -40,6 +42,7 @@ int handle_page_fault(unsigned long address, unsigned long ip, if (in_atomic()) goto out_nosemaphore; +retry: down_read(&mm->mmap_sem); vma = find_vma(mm, address); if (!vma) @@ -65,7 +68,11 @@ good_area: do { int 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)) + goto out_nosemaphore; + if (unlikely(fault & VM_FAULT_ERROR)) { if (fault & VM_FAULT_OOM) { goto out_of_memory; @@ -75,10 +82,17 @@ good_area: } 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; + + goto retry; + } + } pgd = pgd_offset(mm, address); pud = pud_offset(pgd, address); |