[PATCH 3/3] mm: Move the tlb flushing inside of unmap vmas

From: Haggai Eran <hidden>
Date: 2012-08-26 10:12:30
Subsystem: memory management, memory management - core, memory mapping, the rest · Maintainers: Andrew Morton, David Hildenbrand, Liam R. Howlett, Lorenzo Stoakes, Linus Torvalds

From: Sagi Grimberg <redacted>

This patch removes another hurdle preventing sleeping in mmu notifiers. It is
based on the assumption that we cannot sleep between calls to tlb_gather_mmu,
and tlb_finish_mmu.

Signed-off-by: Sagi Grimberg <redacted>
Signed-off-by: Haggai Eran <redacted>
---
 mm/memory.c | 12 ++++--------
 mm/mmap.c   |  7 -------
 2 files changed, 4 insertions(+), 15 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index e721432..ca2e0cd 100644
--- a/mm/memory.c
+++ b/mm/memory.c

@@ -1327,6 +1327,9 @@ static void unmap_single_vma(struct mmu_gather *tlb,
 	if (end <= vma->vm_start)
 		return;
 
+	lru_add_drain();
+	tlb_gather_mmu(tlb, vma->vm_mm, 0);
+	update_hiwater_rss(vma->vm_mm);
 	if (vma->vm_file)
 		uprobe_munmap(vma, start, end);

@@ -1354,6 +1357,7 @@ static void unmap_single_vma(struct mmu_gather *tlb,
 		} else
 			unmap_page_range(tlb, vma, start, end, details);
 	}
+	tlb_finish_mmu(tlb, start_addr, end_addr);
 }
 
 /**

@@ -1402,14 +1406,10 @@ void zap_page_range(struct vm_area_struct *vma, unsigned long start,
 	struct mmu_gather tlb;
 	unsigned long end = start + size;
 
-	lru_add_drain();
-	tlb_gather_mmu(&tlb, mm, 0);
-	update_hiwater_rss(mm);
 	mmu_notifier_invalidate_range_start(mm, start, end);
 	for ( ; vma && vma->vm_start < end; vma = vma->vm_next)
 		unmap_single_vma(&tlb, vma, start, end, details);
 	mmu_notifier_invalidate_range_end(mm, start, end);
-	tlb_finish_mmu(&tlb, start, end);
 }
 
 /**

@@ -1428,13 +1428,9 @@ static void zap_page_range_single(struct vm_area_struct *vma, unsigned long addr
 	struct mmu_gather tlb;
 	unsigned long end = address + size;
 
-	lru_add_drain();
-	tlb_gather_mmu(&tlb, mm, 0);
-	update_hiwater_rss(mm);
 	mmu_notifier_invalidate_range_start(mm, address, end);
 	unmap_single_vma(&tlb, vma, address, end, details);
 	mmu_notifier_invalidate_range_end(mm, address, end);
-	tlb_finish_mmu(&tlb, address, end);
 }
 
 /**

diff --git a/mm/mmap.c b/mm/mmap.c
index 731da04..4b614fe 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c

@@ -1908,11 +1908,7 @@ static void unmap_region(struct mm_struct *mm,
 	struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
 	struct mmu_gather tlb;
 
-	lru_add_drain();
-	tlb_gather_mmu(&tlb, mm, 0);
-	update_hiwater_rss(mm);
 	unmap_vmas(&tlb, vma, start, end);
-	tlb_finish_mmu(&tlb, start, end);
 	free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS,
 				 next ? next->vm_start : 0);
 }

@@ -2288,14 +2284,11 @@ void exit_mmap(struct mm_struct *mm)
 	if (!vma)	/* Can happen if dup_mmap() received an OOM */
 		return;
 
-	lru_add_drain();
 	flush_cache_mm(mm);
-	tlb_gather_mmu(&tlb, mm, 1);
 	/* update_hiwater_rss(mm) here? but nobody should be looking */
 	/* Use -1 here to ensure all VMAs in the mm are unmapped */
 	unmap_vmas(&tlb, vma, 0, -1);
 
-	tlb_finish_mmu(&tlb, 0, -1);
 	free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
 
 	/*

-- 
1.7.11.2

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