From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-f198.google.com (mail-pl1-f198.google.com [209.85.214.198]) by kanga.kvack.org (Postfix) with ESMTP id 8D3FE6B4450 for ; Mon, 26 Nov 2018 18:16:32 -0500 (EST) Received: by mail-pl1-f198.google.com with SMTP id l9so21851267plt.7 for ; Mon, 26 Nov 2018 15:16:32 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id b13sor2463908pls.16.2018.11.26.15.16.31 for (Google Transport Security); Mon, 26 Nov 2018 15:16:31 -0800 (PST) Date: Mon, 26 Nov 2018 15:16:28 -0800 (PST) From: Hugh Dickins Subject: [PATCH 01/10] mm/huge_memory: rename freeze_page() to unmap_page() Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: "Kirill A. Shutemov" , "Kirill A. Shutemov" , Matthew Wilcox , Jerome Glisse , linux-mm@kvack.org 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. Fixes: e9b61f19858a5 ("thp: reintroduce split_huge_page()") Signed-off-by: Hugh Dickins Cc: Kirill A. Shutemov Cc: Jerome Glisse Cc: stable@vger.kernel.org # 4.8+ --- 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 55478ab3c83b..30100fac2341 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2350,7 +2350,7 @@ 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; @@ -2365,7 +2365,7 @@ 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)) { @@ -2483,7 +2483,7 @@ 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; @@ -2664,7 +2664,7 @@ 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)) { @@ -2673,7 +2673,7 @@ 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 */ @@ -2727,7 +2727,7 @@ 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. -- 2.20.0.rc0.387.gc7a69e6b6c-goog