The patch titled
Subject: mm, thp: fix mapped pages avoiding unevictable list on mlock
has been added to the -mm tree. Its filename is
mm-thp-fix-mapped-pages-avoiding-unevictable-list-on-mlock.patch
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From: David Rientjes <rientjes@xxxxxxxxxx>
Subject: mm, thp: fix mapped pages avoiding unevictable list on mlock
When a transparent hugepage is mapped and it is included in an mlock()
range, follow_page() incorrectly avoids setting the page's mlock bit and
moving it to the unevictable lru.
This is evident if you try to mlock(), munlock(), and then mlock() a
range again. Currently:
#define MAP_SIZE (4 << 30) /* 4GB */
void *ptr = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
mlock(ptr, MAP_SIZE);
$ grep -E "Unevictable|Inactive\(anon" /proc/meminfo
Inactive(anon): 6304 kB
Unevictable: 4213924 kB
munlock(ptr, MAP_SIZE);
Inactive(anon): 4186252 kB
Unevictable: 19652 kB
mlock(ptr, MAP_SIZE);
Inactive(anon): 4198556 kB
Unevictable: 21684 kB
Notice that less than 2MB was added to the unevictable list; this is
because these pages in the range are not transparent hugepages since the
4GB range was allocated with mmap() and has no specific alignment. If
posix_memalign() were used instead, unevictable would not have grown at
all on the second mlock().
The fix is to call mlock_vma_page() so that the mlock bit is set and the
page is added to the unevictable list. With this patch:
mlock(ptr, MAP_SIZE);
Inactive(anon): 4056 kB
Unevictable: 4213940 kB
munlock(ptr, MAP_SIZE);
Inactive(anon): 4198268 kB
Unevictable: 19636 kB
mlock(ptr, MAP_SIZE);
Inactive(anon): 4008 kB
Unevictable: 4213940 kB
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michel Lespinasse <walken@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/huge_mm.h | 2 +-
mm/huge_memory.c | 11 ++++++++++-
mm/memory.c | 2 +-
3 files changed, 12 insertions(+), 3 deletions(-)
diff -puN include/linux/huge_mm.h~mm-thp-fix-mapped-pages-avoiding-unevictable-list-on-mlock include/linux/huge_mm.h
--- a/include/linux/huge_mm.h~mm-thp-fix-mapped-pages-avoiding-unevictable-list-on-mlock
+++ a/include/linux/huge_mm.h
@@ -11,7 +11,7 @@ extern int copy_huge_pmd(struct mm_struc
extern int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pmd_t *pmd,
pmd_t orig_pmd);
-extern struct page *follow_trans_huge_pmd(struct mm_struct *mm,
+extern struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
unsigned long addr,
pmd_t *pmd,
unsigned int flags);
diff -puN mm/huge_memory.c~mm-thp-fix-mapped-pages-avoiding-unevictable-list-on-mlock mm/huge_memory.c
--- a/mm/huge_memory.c~mm-thp-fix-mapped-pages-avoiding-unevictable-list-on-mlock
+++ a/mm/huge_memory.c
@@ -1040,11 +1040,12 @@ out_unlock:
return ret;
}
-struct page *follow_trans_huge_pmd(struct mm_struct *mm,
+struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
unsigned long addr,
pmd_t *pmd,
unsigned int flags)
{
+ struct mm_struct *mm = vma->vm_mm;
struct page *page = NULL;
assert_spin_locked(&mm->page_table_lock);
@@ -1067,6 +1068,14 @@ struct page *follow_trans_huge_pmd(struc
_pmd = pmd_mkyoung(pmd_mkdirty(*pmd));
set_pmd_at(mm, addr & HPAGE_PMD_MASK, pmd, _pmd);
}
+ if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
+ if (page->mapping && trylock_page(page)) {
+ lru_add_drain();
+ if (page->mapping)
+ mlock_vma_page(page);
+ unlock_page(page);
+ }
+ }
page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT;
VM_BUG_ON(!PageCompound(page));
if (flags & FOLL_GET)
diff -puN mm/memory.c~mm-thp-fix-mapped-pages-avoiding-unevictable-list-on-mlock mm/memory.c
--- a/mm/memory.c~mm-thp-fix-mapped-pages-avoiding-unevictable-list-on-mlock
+++ a/mm/memory.c
@@ -1533,7 +1533,7 @@ struct page *follow_page(struct vm_area_
spin_unlock(&mm->page_table_lock);
wait_split_huge_page(vma->anon_vma, pmd);
} else {
- page = follow_trans_huge_pmd(mm, address,
+ page = follow_trans_huge_pmd(vma, address,
pmd, flags);
spin_unlock(&mm->page_table_lock);
goto out;
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
origin.patch
linux-next.patch
acpi_memhotplugc-fix-memory-leak-when-memory-device-is-unbound-from-the-module-acpi_memhotplug.patch
acpi_memhotplugc-free-memory-device-if-acpi_memory_enable_device-failed.patch
acpi_memhotplugc-remove-memory-info-from-list-before-freeing-it.patch
acpi_memhotplugc-dont-allow-to-eject-the-memory-device-if-it-is-being-used.patch
acpi_memhotplugc-bind-the-memory-device-when-the-driver-is-being-loaded.patch
acpi_memhotplugc-auto-bind-the-memory-device-which-is-hotplugged-before-the-driver-is-loaded.patch
mm-mmapc-replace-find_vma_prepare-with-clearer-find_vma_links-fix.patch
oom-remove-deprecated-oom_adj.patch
thp-fix-the-count-of-thp_collapse_alloc.patch
thp-remove-unnecessary-check-in-start_khugepaged.patch
thp-move-khugepaged_mutex-out-of-khugepaged.patch
thp-remove-unnecessary-khugepaged_thread-check.patch
thp-remove-wake_up_interruptible-in-the-exit-path.patch
thp-remove-some-code-depend-on-config_numa.patch
thp-merge-page-pre-alloc-in-khugepaged_loop-into-khugepaged_do_scan.patch
thp-release-page-in-page-pre-alloc-path.patch
thp-introduce-khugepaged_prealloc_page-and-khugepaged_alloc_page.patch
thp-remove-khugepaged_loop.patch
thp-use-khugepaged_enabled-to-remove-duplicate-code.patch
thp-remove-unnecessary-set_recommended_min_free_kbytes.patch
mm-page_alloc-refactor-out-__alloc_contig_migrate_alloc.patch
memory-hotplug-dont-replace-lowmem-pages-with-highmem.patch
thp-khugepaged_prealloc_page-forgot-to-reset-the-page-alloc-indicator.patch
mm-fix-up-zone-present-pages.patch
mm-numa-reclaim-from-all-nodes-within-reclaim-distance.patch
mm-numa-reclaim-from-all-nodes-within-reclaim-distance-fix.patch
mm-numa-reclaim-from-all-nodes-within-reclaim-distance-fix-fix.patch
hugetlb-do-not-use-vma_hugecache_offset-for-vma_prio_tree_foreach.patch
mm-revert-0def08e3-mm-mempolicyc-check-return-code-of-check_range.patch
mm-revert-0def08e3-mm-mempolicyc-check-return-code-of-check_range-fix.patch
kpageflags-fix-wrong-kpf_thp-on-non-huge-compound-pages.patch
memory-hotplug-preparation-to-notify-memory-blocks-state-at-memory-hot-remove.patch
memory-hotplug-update-memory-blocks-state-and-notfy-theinformation-to-userspace.patch
mm-huge_memoryc-fix-build-warning-for-uma-kernels.patch
mm-thp-fix-mapped-pages-avoiding-unevictable-list-on-mlock.patch
mm-thp-fix-mlock-statistics.patch
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