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authorChristoph Lameter <clameter@sgi.com>2006-02-01 03:05:39 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-01 08:53:16 -0800
commita3351e525e4768c29aa5d22ef59b5b38e0361e53 (patch)
tree457ab54f402b471c5158e8b361d059e88ab8cd62
parenta48d07afdf18212de22b959715b16793c5a6e57a (diff)
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[PATCH] Direct Migration V9: remove_from_swap() to remove swap ptes
Add remove_from_swap remove_from_swap() allows the restoration of the pte entries that existed before page migration occurred for anonymous pages by walking the reverse maps. This reduces swap use and establishes regular pte's without the need for page faults. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--include/linux/rmap.h1
-rw-r--r--include/linux/swap.h1
-rw-r--r--mm/rmap.c29
-rw-r--r--mm/swapfile.c9
-rw-r--r--mm/vmscan.c9
5 files changed, 49 insertions, 0 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 0f1ea2d..d6b9bcd 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -92,6 +92,7 @@ static inline void page_dup_rmap(struct page *page)
*/
int page_referenced(struct page *, int is_locked);
int try_to_unmap(struct page *, int ignore_refs);
+void remove_from_swap(struct page *page);
/*
* Called from mm/filemap_xip.c to unmap empty zero page
diff --git a/include/linux/swap.h b/include/linux/swap.h
index d359fc0..229b6d0 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -248,6 +248,7 @@ extern int remove_exclusive_swap_page(struct page *);
struct backing_dev_info;
extern spinlock_t swap_lock;
+extern int remove_vma_swap(struct vm_area_struct *vma, struct page *page);
/* linux/mm/thrash.c */
extern struct mm_struct * swap_token_mm;
diff --git a/mm/rmap.c b/mm/rmap.c
index 13fad5f..f4b91d7 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -206,6 +206,35 @@ out:
return anon_vma;
}
+#ifdef CONFIG_MIGRATION
+/*
+ * Remove an anonymous page from swap replacing the swap pte's
+ * through real pte's pointing to valid pages and then releasing
+ * the page from the swap cache.
+ *
+ * Must hold page lock on page.
+ */
+void remove_from_swap(struct page *page)
+{
+ struct anon_vma *anon_vma;
+ struct vm_area_struct *vma;
+
+ if (!PageAnon(page) || !PageSwapCache(page))
+ return;
+
+ anon_vma = page_lock_anon_vma(page);
+ if (!anon_vma)
+ return;
+
+ list_for_each_entry(vma, &anon_vma->head, anon_vma_node)
+ remove_vma_swap(vma, page);
+
+ spin_unlock(&anon_vma->lock);
+
+ delete_from_swap_cache(page);
+}
+#endif
+
/*
* At what user virtual address is page expected in vma?
*/
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 9678182..1f9cf0d 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -554,6 +554,15 @@ static int unuse_mm(struct mm_struct *mm,
return 0;
}
+#ifdef CONFIG_MIGRATION
+int remove_vma_swap(struct vm_area_struct *vma, struct page *page)
+{
+ swp_entry_t entry = { .val = page_private(page) };
+
+ return unuse_vma(vma, entry, page);
+}
+#endif
+
/*
* Scan swap_map from current position to next entry still in use.
* Recycle to start on reaching the end, returning 0 when empty.
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8f326ce..5e98b86 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -804,6 +804,15 @@ int migrate_page(struct page *newpage, struct page *page)
migrate_page_copy(newpage, page);
+ /*
+ * Remove auxiliary swap entries and replace
+ * them with real ptes.
+ *
+ * Note that a real pte entry will allow processes that are not
+ * waiting on the page lock to use the new page via the page tables
+ * before the new page is unlocked.
+ */
+ remove_from_swap(newpage);
return 0;
}