4.19-stable review patch. If anyone has any objections, please let me know.
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commit 906f9cdfc2a0800f13683f9e4ebdfd08c12ee81b upstream.
The term "freeze" is used in several ways in the kernel, and in mm it has the particular meaning of forcing page refcount temporarily to 0. freeze_page() is just too confusing a name for a function that unmaps a page: rename it unmap_page(), and rename unfreeze_page() remap_page().
Went to change the mention of freeze_page() added later in mm/rmap.c, but found it to be incorrect: ordinary page reclaim reaches there too; but the substance of the comment still seems correct, so edit it down.
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261514080.2275@eggly.anvils Fixes: e9b61f19858a5 ("thp: reintroduce split_huge_page()") Signed-off-by: Hugh Dickins hughd@google.com Acked-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Cc: Jerome Glisse jglisse@redhat.com Cc: Konstantin Khlebnikov khlebnikov@yandex-team.ru Cc: Matthew Wilcox willy@infradead.org Cc: stable@vger.kernel.org [4.8+] Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- mm/huge_memory.c | 12 ++++++------ mm/rmap.c | 13 +++---------- 2 files changed, 9 insertions(+), 16 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index deed97fba979..ef573d719eb4 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2322,7 +2322,7 @@ void vma_adjust_trans_huge(struct vm_area_struct *vma, } }
-static void freeze_page(struct page *page) +static void unmap_page(struct page *page) { enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; @@ -2337,7 +2337,7 @@ static void freeze_page(struct page *page) VM_BUG_ON_PAGE(!unmap_success, page); }
-static void unfreeze_page(struct page *page) +static void remap_page(struct page *page) { int i; if (PageTransHuge(page)) { @@ -2454,7 +2454,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags);
- unfreeze_page(head); + remap_page(head);
for (i = 0; i < HPAGE_PMD_NR; i++) { struct page *subpage = head + i; @@ -2635,7 +2635,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) }
/* - * Racy check if we can split the page, before freeze_page() will + * Racy check if we can split the page, before unmap_page() will * split PMDs */ if (!can_split_huge_page(head, &extra_pins)) { @@ -2644,7 +2644,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) }
mlocked = PageMlocked(page); - freeze_page(head); + unmap_page(head); VM_BUG_ON_PAGE(compound_mapcount(head), head);
/* Make sure the page is not on per-CPU pagevec as it takes pin */ @@ -2701,7 +2701,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) fail: if (mapping) xa_unlock(&mapping->i_pages); spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); - unfreeze_page(head); + remap_page(head); ret = -EBUSY; }
diff --git a/mm/rmap.c b/mm/rmap.c index 1e79fac3186b..85b7f9423352 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1627,16 +1627,9 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, address + PAGE_SIZE); } else { /* - * We should not need to notify here as we reach this - * case only from freeze_page() itself only call from - * split_huge_page_to_list() so everything below must - * be true: - * - page is not anonymous - * - page is locked - * - * So as it is a locked file back page thus it can not - * be remove from the page cache and replace by a new - * page before mmu_notifier_invalidate_range_end so no + * This is a locked file-backed page, thus it cannot + * be removed from the page cache and replaced by a new + * page before mmu_notifier_invalidate_range_end, so no * concurrent thread might update its page table to * point at new page while a device still is using this * page.