The patch titled
Subject: mm: adjust FOLL_SPLIT for new refcounting
has been added to the -mm tree. Its filename is
mm-adjust-foll_split-for-new-refcounting.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-adjust-foll_split-for-new-refcounting.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-adjust-foll_split-for-new-refcounting.patch
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------------------------------------------------------
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: mm: adjust FOLL_SPLIT for new refcounting
We need to prepare kernel to allow transhuge pages to be mapped with
ptes too. We need to handle FOLL_SPLIT in follow_page_pte().
Also we use split_huge_page() directly instead of split_huge_page_pmd().
split_huge_page_pmd() will gone.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Tested-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Acked-by: Jerome Marchand <jmarchan@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Steve Capper <steve.capper@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/gup.c | 67 ++++++++++++++++++++++++++++++++++++++---------------
1 file changed, 49 insertions(+), 18 deletions(-)
diff -puN mm/gup.c~mm-adjust-foll_split-for-new-refcounting mm/gup.c
--- a/mm/gup.c~mm-adjust-foll_split-for-new-refcounting
+++ a/mm/gup.c
@@ -116,6 +116,19 @@ retry:
}
}
+ if (flags & FOLL_SPLIT && PageTransCompound(page)) {
+ int ret;
+ get_page(page);
+ pte_unmap_unlock(ptep, ptl);
+ lock_page(page);
+ ret = split_huge_page(page);
+ unlock_page(page);
+ put_page(page);
+ if (ret)
+ return ERR_PTR(ret);
+ goto retry;
+ }
+
if (flags & FOLL_GET)
get_page_foll(page);
if (flags & FOLL_TOUCH) {
@@ -220,27 +233,45 @@ struct page *follow_page_mask(struct vm_
}
if ((flags & FOLL_NUMA) && pmd_protnone(*pmd))
return no_page_table(vma, flags);
- if (pmd_trans_huge(*pmd)) {
- if (flags & FOLL_SPLIT) {
+ if (likely(!pmd_trans_huge(*pmd)))
+ return follow_page_pte(vma, address, pmd, flags);
+
+ ptl = pmd_lock(mm, pmd);
+ if (unlikely(!pmd_trans_huge(*pmd))) {
+ spin_unlock(ptl);
+ return follow_page_pte(vma, address, pmd, flags);
+ }
+
+ if (unlikely(pmd_trans_splitting(*pmd))) {
+ spin_unlock(ptl);
+ wait_split_huge_page(vma->anon_vma, pmd);
+ return follow_page_pte(vma, address, pmd, flags);
+ }
+
+ if (flags & FOLL_SPLIT) {
+ int ret;
+ page = pmd_page(*pmd);
+ if (is_huge_zero_page(page)) {
+ spin_unlock(ptl);
+ ret = 0;
split_huge_page_pmd(vma, address, pmd);
- return follow_page_pte(vma, address, pmd, flags);
- }
- ptl = pmd_lock(mm, pmd);
- if (likely(pmd_trans_huge(*pmd))) {
- if (unlikely(pmd_trans_splitting(*pmd))) {
- spin_unlock(ptl);
- wait_split_huge_page(vma->anon_vma, pmd);
- } else {
- page = follow_trans_huge_pmd(vma, address,
- pmd, flags);
- spin_unlock(ptl);
- *page_mask = HPAGE_PMD_NR - 1;
- return page;
- }
- } else
+ } else {
+ get_page(page);
spin_unlock(ptl);
+ lock_page(page);
+ ret = split_huge_page(page);
+ unlock_page(page);
+ put_page(page);
+ }
+
+ return ret ? ERR_PTR(ret) :
+ follow_page_pte(vma, address, pmd, flags);
}
- return follow_page_pte(vma, address, pmd, flags);
+
+ page = follow_trans_huge_pmd(vma, address, pmd, flags);
+ spin_unlock(ptl);
+ *page_mask = HPAGE_PMD_NR - 1;
+ return page;
}
static int get_gate_page(struct mm_struct *mm, unsigned long address,
_
Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are
rcu-force-alignment-on-struct-callback_head-rcu_head.patch
mm-make-optimistic-check-for-swapin-readahead-fix.patch
mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix.patch
mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix-2.patch
mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix-3.patch
mm-drop-page-slab_page.patch
slab-slub-use-page-rcu_head-instead-of-page-lru-plus-cast.patch
zsmalloc-use-page-private-instead-of-page-first_page.patch
mm-pack-compound_dtor-and-compound_order-into-one-word-in-struct-page.patch
mm-make-compound_head-robust.patch
mm-make-compound_head-robust-fix.patch
mm-use-unsigned-int-for-page-order.patch
mm-use-unsigned-int-for-compound_dtor-compound_order-on-64bit.patch
page-flags-trivial-cleanup-for-pagetrans-helpers.patch
page-flags-move-code-around.patch
page-flags-introduce-page-flags-policies-wrt-compound-pages.patch
page-flags-introduce-page-flags-policies-wrt-compound-pages-fix.patch
page-flags-introduce-page-flags-policies-wrt-compound-pages-fix-fix.patch
page-flags-introduce-page-flags-policies-wrt-compound-pages-fix-3.patch
page-flags-define-pg_locked-behavior-on-compound-pages.patch
page-flags-define-behavior-of-fs-io-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-lru-related-flags-on-compound-pages.patch
page-flags-define-behavior-slb-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-xen-related-flags-on-compound-pages.patch
page-flags-define-pg_reserved-behavior-on-compound-pages.patch
page-flags-define-pg_reserved-behavior-on-compound-pages-fix.patch
page-flags-define-pg_swapbacked-behavior-on-compound-pages.patch
page-flags-define-pg_swapcache-behavior-on-compound-pages.patch
page-flags-define-pg_mlocked-behavior-on-compound-pages.patch
page-flags-define-pg_uncached-behavior-on-compound-pages.patch
page-flags-define-pg_uptodate-behavior-on-compound-pages.patch
page-flags-look-at-head-page-if-the-flag-is-encoded-in-page-mapping.patch
mm-sanitize-page-mapping-for-tail-pages.patch
mm-proc-adjust-pss-calculation.patch
rmap-add-argument-to-charge-compound-page.patch
memcg-adjust-to-support-new-thp-refcounting.patch
mm-thp-adjust-conditions-when-we-can-reuse-the-page-on-wp-fault.patch
mm-adjust-foll_split-for-new-refcounting.patch
mm-handle-pte-mapped-tail-pages-in-gerneric-fast-gup-implementaiton.patch
thp-mlock-do-not-allow-huge-pages-in-mlocked-area.patch
khugepaged-ignore-pmd-tables-with-thp-mapped-with-ptes.patch
thp-rename-split_huge_page_pmd-to-split_huge_pmd.patch
mm-vmstats-new-thp-splitting-event.patch
mm-temporally-mark-thp-broken.patch
thp-drop-all-split_huge_page-related-code.patch
mm-drop-tail-page-refcounting.patch
futex-thp-remove-special-case-for-thp-in-get_futex_key.patch
ksm-prepare-to-new-thp-semantics.patch
mm-thp-remove-compound_lock.patch
arm64-thp-remove-infrastructure-for-handling-splitting-pmds.patch
arm-thp-remove-infrastructure-for-handling-splitting-pmds.patch
mips-thp-remove-infrastructure-for-handling-splitting-pmds.patch
powerpc-thp-remove-infrastructure-for-handling-splitting-pmds.patch
s390-thp-remove-infrastructure-for-handling-splitting-pmds.patch
sparc-thp-remove-infrastructure-for-handling-splitting-pmds.patch
tile-thp-remove-infrastructure-for-handling-splitting-pmds.patch
x86-thp-remove-infrastructure-for-handling-splitting-pmds.patch
mm-thp-remove-infrastructure-for-handling-splitting-pmds.patch
mm-rework-mapcount-accounting-to-enable-4k-mapping-of-thps.patch
mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages.patch
mm-numa-skip-pte-mapped-thp-on-numa-fault.patch
thp-implement-split_huge_pmd.patch
thp-add-option-to-setup-migration-entries-during-pmd-split.patch
thp-mm-split_huge_page-caller-need-to-lock-page.patch
thp-reintroduce-split_huge_page.patch
migrate_pages-try-to-split-pages-on-qeueuing.patch
thp-introduce-deferred_split_huge_page.patch
mm-re-enable-thp.patch
thp-update-documentation.patch
thp-allow-mlocked-thp-again.patch
mm-support-madvisemadv_free-fix-3.patch
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