Subject: + mm-numa-recheck-for-transhuge-pages-under-lock-during-protection-changes-fix.patch added to -mm tree
To: mgorman@xxxxxxx,riel@xxxxxxxxxx,sasha.levin@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Fri, 21 Mar 2014 15:07:06 -0700
The patch titled
Subject: mm-numa-recheck-for-transhuge-pages-under-lock-during-protection-changes-fix
has been added to the -mm tree. Its filename is
mm-numa-recheck-for-transhuge-pages-under-lock-during-protection-changes-fix.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-numa-recheck-for-transhuge-pages-under-lock-during-protection-changes-fix.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-numa-recheck-for-transhuge-pages-under-lock-during-protection-changes-fix.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 ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxx>
Subject: mm-numa-recheck-for-transhuge-pages-under-lock-during-protection-changes-fix
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Cc: Sasha Levin <sasha.levin@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mprotect.c | 40 ++++++++++++++++++++++++++++++----------
1 file changed, 30 insertions(+), 10 deletions(-)
diff -puN mm/mprotect.c~mm-numa-recheck-for-transhuge-pages-under-lock-during-protection-changes-fix mm/mprotect.c
--- a/mm/mprotect.c~mm-numa-recheck-for-transhuge-pages-under-lock-during-protection-changes-fix
+++ a/mm/mprotect.c
@@ -36,6 +36,34 @@ static inline pgprot_t pgprot_modify(pgp
}
#endif
+/*
+ * For a prot_numa update we only hold mmap_sem for read so there is a
+ * potential race with faulting where a pmd was temporarily none. This
+ * function checks for a transhuge pmd under the appropriate lock. It
+ * returns a pte if it was successfully locked or NULL if it raced with
+ * a transhuge insertion.
+ */
+static pte_t *lock_pte_protection(struct vm_area_struct *vma, pmd_t *pmd,
+ unsigned long addr, int prot_numa, spinlock_t **ptl)
+{
+ pte_t *pte;
+ spinlock_t *pmdl;
+
+ /* !prot_numa is protected by mmap_sem held for write */
+ if (!prot_numa)
+ return pte_offset_map_lock(vma->vm_mm, pmd, addr, ptl);
+
+ pmdl = pmd_lock(vma->vm_mm, pmd);
+ if (unlikely(pmd_trans_huge(*pmd) || pmd_none(*pmd))) {
+ spin_unlock(pmdl);
+ return NULL;
+ }
+
+ pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, ptl);
+ spin_unlock(pmdl);
+ return pte;
+}
+
static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long end, pgprot_t newprot,
int dirty_accountable, int prot_numa)
@@ -45,17 +73,9 @@ static unsigned long change_pte_range(st
spinlock_t *ptl;
unsigned long pages = 0;
- pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
-
- /*
- * For a prot_numa update we only hold mmap_sem for read so there is a
- * potential race with faulting where a pmd was temporarily none so
- * recheck it under the lock and bail if we race
- */
- if (prot_numa && unlikely(pmd_trans_huge(*pmd))) {
- pte_unmap_unlock(pte, ptl);
+ pte = lock_pte_protection(vma, pmd, addr, prot_numa, &ptl);
+ if (!pte)
return 0;
- }
arch_enter_lazy_mmu_mode();
do {
_
Patches currently in -mm which might be from mgorman@xxxxxxx are
mm-vmscan-respect-numa-policy-mask-when-shrinking-slab-on-direct-reclaim.patch
mm-vmscan-move-call-to-shrink_slab-to-shrink_zones.patch
mm-vmscan-remove-shrink_control-arg-from-do_try_to_free_pages.patch
mm-compaction-ignore-pageblock-skip-when-manually-invoking-compaction.patch
mm-optimize-put_mems_allowed-usage.patch
mm-vmstat-fix-up-zone-state-accounting.patch
fs-cachefiles-use-add_to_page_cache_lru.patch
lib-radix-tree-radix_tree_delete_item.patch
mm-shmem-save-one-radix-tree-lookup-when-truncating-swapped-pages.patch
mm-filemap-move-radix-tree-hole-searching-here.patch
mm-fs-prepare-for-non-page-entries-in-page-cache-radix-trees.patch
mm-fs-store-shadow-entries-in-page-cache.patch
mm-thrash-detection-based-file-cache-sizing.patch
lib-radix_tree-tree-node-interface.patch
mm-keep-page-cache-radix-tree-nodes-in-check.patch
mm-compaction-avoid-isolating-pinned-pages.patch
mm-rename-__do_fault-do_fault.patch
mm-do_fault-extract-to-call-vm_ops-do_fault-to-separate-function.patch
mm-introduce-do_read_fault.patch
mm-introduce-do_cow_fault.patch
mm-introduce-do_shared_fault-and-drop-do_fault.patch
mm-introduce-do_shared_fault-and-drop-do_fault-fix.patch
mm-introduce-do_shared_fault-and-drop-do_fault-fix-fix.patch
mm-consolidate-code-to-call-vm_ops-page_mkwrite.patch
mm-consolidate-code-to-call-vm_ops-page_mkwrite-fix.patch
mm-consolidate-code-to-setup-pte.patch
mm-numa-recheck-for-transhuge-pages-under-lock-during-protection-changes.patch
mm-numa-recheck-for-transhuge-pages-under-lock-during-protection-changes-fix.patch
mm-vmscan-restore-sc-gfp_mask-after-promoting-it-to-__gfp_highmem.patch
mm-vmscan-do-not-check-compaction_ready-on-promoted-zones.patch
mm-exclude-memory-less-nodes-from-zone_reclaim.patch
mm-compaction-disallow-high-order-page-for-migration-target.patch
mm-compaction-do-not-call-suitable_migration_target-on-every-page.patch
mm-compaction-change-the-timing-to-check-to-drop-the-spinlock.patch
mm-compaction-check-pageblock-suitability-once-per-pageblock.patch
mm-compaction-clean-up-code-on-success-of-ballon-isolation.patch
mm-revert-thp-make-madv_hugepage-check-for-mm-def_flags.patch
mm-revert-thp-make-madv_hugepage-check-for-mm-def_flags-ignore-madv_hugepage-on-s390-to-prevent-sigsegv-in-qemu.patch
mm-thp-add-vm_init_def_mask-and-prctl_thp_disable.patch
exec-kill-the-unnecessary-mm-def_flags-setting-in-load_elf_binary.patch
mm-introduce-vm_ops-map_pages.patch
mm-implement-map_pages-for-page-cache.patch
mm-cleanup-size-checks-in-filemap_fault-and-filemap_map_pages.patch
mm-add-debugfs-tunable-for-fault_around_order.patch
mm-implement-map_pages-for-shmem-tmpfs.patch
fork-collapse-copy_flags-into-copy_process.patch
mm-mempolicy-rename-slab_node-for-clarity.patch
mm-mempolicy-remove-per-process-flag.patch
res_counter-remove-interface-for-locked-charging-and-uncharging.patch
mm-compactionc-isolate_freepages_block-small-tuneup.patch
mm-compaction-determine-isolation-mode-only-once.patch
mm-page_alloc-spill-to-remote-nodes-before-waking-kswapd.patch
mm-try_to_unmap_cluster-should-lock_page-before-mlocking.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
linux-next.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
