[PATCH] hugetlbfs: Kill applications that use MAP_NORESERVE with SIGBUS instead of OOM-killer
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From: Mel Gorman on 20 Apr 2010 13:50 Ordinarily, application using hugetlbfs will create mappings with reserves. For shared mappings, these pages are reserved before mmap() returns success and for private mappings, the caller process is guaranteed and a child process that cannot get the pages gets killed with sigbus. An application that uses MAP_NORESERVE gets no reservations and mmap() will always succeed at the risk the page will not be available at fault time. This might be used for example on very large sparse mappings where the developer is confident the necessary huge pages exist to satisfy all faults even though the whole mapping cannot be backed by huge pages. Unfortunately, if an allocation does fail, VM_FAULT_OOM is returned to the fault handler which proceeds to trigger the OOM-killer. This is unhelpful. This patch alters hugetlbfs to kill a process that uses MAP_NORESERVE where huge pages were not available with SIGBUS instead of triggering the OOM killer. This patch if accepted should also be considered a -stable candidate. Signed-off-by: Mel Gorman <mel(a)csn.ul.ie> --- mm/hugetlb.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 6034dc9..af2d907 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1038,7 +1038,7 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, page = alloc_buddy_huge_page(h, vma, addr); if (!page) { hugetlb_put_quota(inode->i_mapping, chg); - return ERR_PTR(-VM_FAULT_OOM); + return ERR_PTR(-VM_FAULT_SIGBUS); } } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |