The patch titled
Subject: hugetlb, mbind: fall back to default policy if vma is NULL
has been added to the -mm tree. Its filename is
hugetlb-mbind-fall-back-to-default-policy-if-vma-is-null.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/hugetlb-mbind-fall-back-to-default-policy-if-vma-is-null.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/hugetlb-mbind-fall-back-to-default-policy-if-vma-is-null.patch
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*** 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: Michal Hocko <mhocko@xxxxxxxx>
Subject: hugetlb, mbind: fall back to default policy if vma is NULL
Dan Carpenter has noticed that mbind migration callback (new_page) can get
a NULL vma pointer and choke on it inside alloc_huge_page_vma which relies
on the VMA to get the hstate. We used to BUG_ON this case but the BUG_+ON
has been removed recently by "hugetlb, mempolicy: fix the mbind hugetlb
migration".
The proper way to handle this is to get the hstate from the migrated page
and rely on huge_node (resp. get_vma_policy) do the right thing with null
VMA. We are currently falling back to the default mempolicy in that case
which is in line what THP path is doing here.
Link: http://lkml.kernel.org/r/20180110104712.GR1732@xxxxxxxxxxxxxx
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/hugetlb.h | 5 +++--
mm/hugetlb.c | 5 ++---
mm/mempolicy.c | 3 ++-
3 files changed, 7 insertions(+), 6 deletions(-)
diff -puN include/linux/hugetlb.h~hugetlb-mbind-fall-back-to-default-policy-if-vma-is-null include/linux/hugetlb.h
--- a/include/linux/hugetlb.h~hugetlb-mbind-fall-back-to-default-policy-if-vma-is-null
+++ a/include/linux/hugetlb.h
@@ -358,7 +358,8 @@ struct page *alloc_huge_page(struct vm_a
struct page *alloc_huge_page_node(struct hstate *h, int nid);
struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
nodemask_t *nmask);
-struct page *alloc_huge_page_vma(struct vm_area_struct *vma, unsigned long address);
+struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
+ unsigned long address);
int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
pgoff_t idx);
@@ -536,7 +537,7 @@ struct hstate {};
#define alloc_huge_page(v, a, r) NULL
#define alloc_huge_page_node(h, nid) NULL
#define alloc_huge_page_nodemask(h, preferred_nid, nmask) NULL
-#define alloc_huge_page_vma(vma, address) NULL
+#define alloc_huge_page_vma(h, vma, address) NULL
#define alloc_bootmem_huge_page(h) NULL
#define hstate_file(f) NULL
#define hstate_sizelog(s) NULL
diff -puN mm/hugetlb.c~hugetlb-mbind-fall-back-to-default-policy-if-vma-is-null mm/hugetlb.c
--- a/mm/hugetlb.c~hugetlb-mbind-fall-back-to-default-policy-if-vma-is-null
+++ a/mm/hugetlb.c
@@ -1675,16 +1675,15 @@ struct page *alloc_huge_page_nodemask(st
}
/* mempolicy aware migration callback */
-struct page *alloc_huge_page_vma(struct vm_area_struct *vma, unsigned long address)
+struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
+ unsigned long address)
{
struct mempolicy *mpol;
nodemask_t *nodemask;
struct page *page;
- struct hstate *h;
gfp_t gfp_mask;
int node;
- h = hstate_vma(vma);
gfp_mask = htlb_alloc_mask(h);
node = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
page = alloc_huge_page_nodemask(h, node, nodemask);
diff -puN mm/mempolicy.c~hugetlb-mbind-fall-back-to-default-policy-if-vma-is-null mm/mempolicy.c
--- a/mm/mempolicy.c~hugetlb-mbind-fall-back-to-default-policy-if-vma-is-null
+++ a/mm/mempolicy.c
@@ -1097,7 +1097,8 @@ static struct page *new_page(struct page
}
if (PageHuge(page)) {
- return alloc_huge_page_vma(vma, address);
+ return alloc_huge_page_vma(page_hstate(compound_head(page)),
+ vma, address);
} else if (PageTransHuge(page)) {
struct page *thp;
_
Patches currently in -mm which might be from mhocko@xxxxxxxx are
mm-drop-hotplug-lock-from-lru_add_drain_all.patch
mm-hugetlb-drop-hugepages_treat_as_movable-sysctl.patch
mm-introduce-map_fixed_safe.patch
fs-elf-drop-map_fixed-usage-from-elf_map.patch
fs-elf-drop-map_fixed-usage-from-elf_map-fix-fix.patch
mm-numa-rework-do_pages_move.patch
mm-migrate-remove-reason-argument-from-new_page_t.patch
mm-migrate-remove-reason-argument-from-new_page_t-fix-3.patch
mm-unclutter-thp-migration.patch
mm-hugetlb-unify-core-page-allocation-accounting-and-initialization.patch
mm-hugetlb-integrate-giga-hugetlb-more-naturally-to-the-allocation-path.patch
mm-hugetlb-do-not-rely-on-overcommit-limit-during-migration.patch
mm-hugetlb-get-rid-of-surplus-page-accounting-tricks.patch
mm-hugetlb-further-simplify-hugetlb-allocation-api.patch
hugetlb-mempolicy-fix-the-mbind-hugetlb-migration.patch
hugetlb-mbind-fall-back-to-default-policy-if-vma-is-null.patch
--
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