The patch titled hugetlb: fix a hugepage reservation check for MAP_SHARED has been added to the -mm tree. Its filename is hugetlb-fix-a-hugepage-reservation-check-for-map_shared.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: hugetlb: fix a hugepage reservation check for MAP_SHARED From: Mel Gorman <mel@xxxxxxxxx> When removing a huge page from the hugepage pool for a fault the system checks to see if the mapping requires additional pages to be reserved, and if it does whether there are any unreserved pages remaining. If not, the allocation fails without even attempting to get a page. In order to determine whether to apply this check we call vma_has_private_reserves() which tells us if this vma is MAP_PRIVATE and is the owner. This incorrectly triggers the remaining reservation test for MAP_SHARED mappings which prevents allocation of the final page in the pool even though it is reserved for this mapping. In reality we only want to check this for MAP_PRIVATE mappings where the process is not the original mapper. Replace vma_has_private_reserves() with vma_has_reserves() which indicates whether further reserves are required, and update the caller. Signed-off-by: Mel Gorman <mel@xxxxxxxxx> Acked-by: Adam Litke <agl@xxxxxxxxxx> Cc: Andy Whitcroft <apw@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/hugetlb.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff -puN mm/hugetlb.c~hugetlb-fix-a-hugepage-reservation-check-for-map_shared mm/hugetlb.c --- a/mm/hugetlb.c~hugetlb-fix-a-hugepage-reservation-check-for-map_shared +++ a/mm/hugetlb.c @@ -342,13 +342,13 @@ void reset_vma_resv_huge_pages(struct vm } /* Returns true if the VMA has associated reserve pages */ -static int vma_has_private_reserves(struct vm_area_struct *vma) +static int vma_has_reserves(struct vm_area_struct *vma) { if (vma->vm_flags & VM_SHARED) - return 0; - if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) - return 0; - return 1; + return 1; + if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) + return 1; + return 0; } static void clear_huge_page(struct page *page, @@ -420,7 +420,7 @@ static struct page *dequeue_huge_page_vm * have no page reserves. This check ensures that reservations are * not "stolen". The child may still get SIGKILLed */ - if (!vma_has_private_reserves(vma) && + if (!vma_has_reserves(vma) && h->free_huge_pages - h->resv_huge_pages == 0) return NULL; _ Patches currently in -mm which might be from mel@xxxxxxxxx are linux-next.patch mm-add-a-basic-debugging-framework-for-memory-initialisation.patch mm-add-a-basic-debugging-framework-for-memory-initialisation-fix.patch mm-verify-the-page-links-and-memory-model.patch mm-make-defensive-checks-around-pfn-values-registered-for-memory-usage.patch mm-print-out-the-zonelists-on-request-for-manual-verification.patch mm-move-bootmem-descriptors-definition-to-a-single-place.patch mm-fix-free_all_bootmem_core-alignment-check.patch mm-normalize-internal-argument-passing-of-bootmem-data.patch mm-unexport-__alloc_bootmem_core.patch page-allocator-inlnie-some-__alloc_pages-wrappers.patch page-allocator-inlnie-some-__alloc_pages-wrappers-fix.patch hugetlb-move-hugetlb_acct_memory.patch hugetlb-reserve-huge-pages-for-reliable-map_private-hugetlbfs-mappings-until-fork.patch hugetlb-guarantee-that-cow-faults-for-a-process-that-called-mmapmap_private-on-hugetlbfs-will-succeed.patch hugetlb-guarantee-that-cow-faults-for-a-process-that-called-mmapmap_private-on-hugetlbfs-will-succeed-fix.patch hugetlb-guarantee-that-cow-faults-for-a-process-that-called-mmapmap_private-on-hugetlbfs-will-succeed-build-fix.patch hugetlb-guarantee-that-cow-faults-for-a-process-that-called-mmapmap_private-on-hugetlbfs-will-succeed-align-faulting-address-to-a-hugepage-boundary-before-unmapping.patch huge-page-private-reservation-review-cleanups.patch huge-page-private-reservation-review-cleanups-fix.patch mm-record-map_noreserve-status-on-vmas-and-fix-small-page-mprotect-reservations.patch hugetlb-move-reservation-region-support-earlier.patch hugetlb-allow-huge-page-mappings-to-be-created-without-reservations.patch hugetlb-allow-huge-page-mappings-to-be-created-without-reservations-cleanups.patch hugetlb-reservations-fix-hugetlb-map_private-reservations-across-vma-splits-v2.patch mm-remove-mm_init-compilation-dependency-on-config_debug_memory_init.patch mm-create-sys-kernel-mm.patch hugetlb-new-sysfs-interface-hugetlb-hang-off-of-sys-kernel-mm-rather-than-sys-kernel.patch hugetlb-new-sysfs-interface-hugetlb-remove-config_sysfs-dependency.patch hugetlb-fix-race-when-reading-proc-meminfo.patch hugetlb-fix-a-hugepage-reservation-check-for-map_shared.patch hugetlb-quota-is-not-freed-for-unused-reserved-private-huge-pages.patch mm-add-alloc_pages_exact-and-free_pages_exact.patch memory-hotplugallocate-usemap-on-the-section-with-pgdat-take-4.patch memory-hotplug-add-sysfs-removable-attribute-for-hotplug-memory-remove.patch page-owner-tracking-leak-detector.patch add-debugging-aid-for-memory-initialisation-problems.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html