linux-kernel - [PATCH 1/4] mm: drop zap_details::ignore

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Date:   Fri, 16 Dec 2016 17:15:53 +0300
From:   "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To:     Michal Hocko <mhocko@...e.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Rik van Riel <riel@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCH 1/4] mm: drop zap_details::ignore_dirty

The only user of ignore_dirty is oom-reaper. But it doesn't really use
it.

ignore_dirty only has effect on file pages mapped with dirty pte.
But oom-repear skips shared VMAs, so there's no way we can dirty file
pte in them.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
---
 include/linux/mm.h | 1 -
 mm/memory.c        | 6 ------
 mm/oom_kill.c      | 3 +--
 3 files changed, 1 insertion(+), 9 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 4424784ac374..7b8e425ac41c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1148,7 +1148,6 @@ struct zap_details {
 	struct address_space *check_mapping;	/* Check page->mapping if set */
 	pgoff_t	first_index;			/* Lowest page->index to unmap */
 	pgoff_t last_index;			/* Highest page->index to unmap */
-	bool ignore_dirty;			/* Ignore dirty pages */
 	bool check_swap_entries;		/* Check also swap entries */
 };
 
diff --git a/mm/memory.c b/mm/memory.c
index 455c3e628d52..6ac8fa56080f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1155,12 +1155,6 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
 
 			if (!PageAnon(page)) {
 				if (pte_dirty(ptent)) {
-					/*
-					 * oom_reaper cannot tear down dirty
-					 * pages
-					 */
-					if (unlikely(details && details->ignore_dirty))
-						continue;
 					force_flush = 1;
 					set_page_dirty(page);
 				}
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index ec9f11d4f094..f101db68e760 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -465,8 +465,7 @@ static bool __oom_reap_task_mm(struct task_struct *tsk, struct mm_struct *mm)
 {
 	struct mmu_gather tlb;
 	struct vm_area_struct *vma;
-	struct zap_details details = {.check_swap_entries = true,
-				      .ignore_dirty = true};
+	struct zap_details details = {.check_swap_entries = true};
 	bool ret = true;
 
 	/*
-- 
2.10.2