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authorSeth, Rohit <rohit.seth@intel.com>2005-10-18 17:15:12 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2005-10-19 16:56:27 -0400
commit3359b54c8c07338f3a863d1109b42eebccdcf379 (patch)
treef91edd52c71e57ce4b46e3875c9054666ca4e24c /mm
parentbb7e257ef8d8ba43cab356aa1cc1b20d0106d45f (diff)
[PATCH] Handle spurious page fault for hugetlb region
The hugetlb pages are currently pre-faulted. At the time of mmap of hugepages, we populate the new PTEs. It is possible that HW has already cached some of the unused PTEs internally. These stale entries never get a chance to be purged in existing control flow. This patch extends the check in page fault code for hugepages. Check if a faulted address falls with in size for the hugetlb file backing it. We return VM_FAULT_MINOR for these cases (assuming that the arch specific page-faulting code purges the stale entry for the archs that need it). Signed-off-by: Rohit Seth <rohit.seth@intel.com> [ This is apparently arguably an ia64 port bug. But the code won't hurt, and for now it fixes a real problem on some ia64 machines ] Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/memory.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/mm/memory.c b/mm/memory.c
index ae8161f1f459..8c88b973abc5 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2045,8 +2045,18 @@ int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct * vma,
2045 2045
2046 inc_page_state(pgfault); 2046 inc_page_state(pgfault);
2047 2047
2048 if (is_vm_hugetlb_page(vma)) 2048 if (unlikely(is_vm_hugetlb_page(vma))) {
2049 return VM_FAULT_SIGBUS; /* mapping truncation does this. */ 2049 if (valid_hugetlb_file_off(vma, address))
2050 /* We get here only if there was a stale(zero) TLB entry
2051 * (because of HW prefetching).
2052 * Low-level arch code (if needed) should have already
2053 * purged the stale entry as part of this fault handling.
2054 * Here we just return.
2055 */
2056 return VM_FAULT_MINOR;
2057 else
2058 return VM_FAULT_SIGBUS; /* mapping truncation does this. */
2059 }
2050 2060
2051 /* 2061 /*
2052 * We need the page table lock to synchronize with kswapd 2062 * We need the page table lock to synchronize with kswapd