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Message-ID: <alpine.LSU.2.00.1209182052030.11632@eggly.anvils>
Date: Tue, 18 Sep 2012 20:53:45 -0700 (PDT)
From: Hugh Dickins <hughd@...gle.com>
To: Andrew Morton <akpm@...ux-foundation.org>
cc: Mel Gorman <mel@....ul.ie>, Rik van Riel <riel@...hat.com>,
Johannes Weiner <hannes@...xchg.org>,
Michel Lespinasse <walken@...gle.com>,
Ying Han <yinghan@...gle.com>, linux-mm@...ck.org,
linux-kernel@...r.kernel.org
Subject: [PATCH 2/4] mm: remove vma arg from page_evictable
page_evictable(page, vma) is an irritant: almost all its callers pass
NULL for vma. Remove the vma arg and use mlocked_vma_newpage(vma, page)
explicitly in the couple of places it's needed. But in those places we
don't even need page_evictable() itself! They're dealing with a freshly
allocated anonymous page, which has no "mapping" and cannot be mlocked yet.
Signed-off-by: Hugh Dickins <hughd@...gle.com>
Cc: Mel Gorman <mel@....ul.ie>
Cc: Rik van Riel <riel@...hat.com>
Cc: Johannes Weiner <hannes@...xchg.org>
Cc: Michel Lespinasse <walken@...gle.com>
Cc: Ying Han <yinghan@...gle.com>
---
Documentation/vm/unevictable-lru.txt | 10 ++-------
include/linux/swap.h | 2 -
mm/internal.h | 5 +---
mm/ksm.c | 2 -
mm/rmap.c | 2 -
mm/swap.c | 2 -
mm/vmscan.c | 27 ++++++++-----------------
7 files changed, 18 insertions(+), 32 deletions(-)
--- 3.6-rc6.orig/Documentation/vm/unevictable-lru.txt 2012-09-18 15:38:08.000000000 -0700
+++ 3.6-rc6/Documentation/vm/unevictable-lru.txt 2012-09-18 16:39:50.878992976 -0700
@@ -197,12 +197,8 @@ the pages are also "rescued" from the un
freeing them.
page_evictable() also checks for mlocked pages by testing an additional page
-flag, PG_mlocked (as wrapped by PageMlocked()). If the page is NOT mlocked,
-and a non-NULL VMA is supplied, page_evictable() will check whether the VMA is
-VM_LOCKED via is_mlocked_vma(). is_mlocked_vma() will SetPageMlocked() and
-update the appropriate statistics if the vma is VM_LOCKED. This method allows
-efficient "culling" of pages in the fault path that are being faulted in to
-VM_LOCKED VMAs.
+flag, PG_mlocked (as wrapped by PageMlocked()), which is set when a page is
+faulted into a VM_LOCKED vma, or found in a vma being VM_LOCKED.
VMSCAN'S HANDLING OF UNEVICTABLE PAGES
@@ -651,7 +647,7 @@ PAGE RECLAIM IN shrink_*_list()
-------------------------------
shrink_active_list() culls any obviously unevictable pages - i.e.
-!page_evictable(page, NULL) - diverting these to the unevictable list.
+!page_evictable(page) - diverting these to the unevictable list.
However, shrink_active_list() only sees unevictable pages that made it onto the
active/inactive lru lists. Note that these pages do not have PageUnevictable
set - otherwise they would be on the unevictable list and shrink_active_list
--- 3.6-rc6.orig/include/linux/swap.h 2012-09-18 15:38:08.000000000 -0700
+++ 3.6-rc6/include/linux/swap.h 2012-09-18 16:39:50.878992976 -0700
@@ -281,7 +281,7 @@ static inline int zone_reclaim(struct zo
}
#endif
-extern int page_evictable(struct page *page, struct vm_area_struct *vma);
+extern int page_evictable(struct page *page);
extern void check_move_unevictable_pages(struct page **, int nr_pages);
extern unsigned long scan_unevictable_pages;
--- 3.6-rc6.orig/mm/internal.h 2012-09-18 15:38:08.000000000 -0700
+++ 3.6-rc6/mm/internal.h 2012-09-18 16:39:50.882992906 -0700
@@ -167,9 +167,8 @@ static inline void munlock_vma_pages_all
}
/*
- * Called only in fault path via page_evictable() for a new page
- * to determine if it's being mapped into a LOCKED vma.
- * If so, mark page as mlocked.
+ * Called only in fault path, to determine if a new page is being
+ * mapped into a LOCKED vma. If it is, mark page as mlocked.
*/
static inline int mlocked_vma_newpage(struct vm_area_struct *vma,
struct page *page)
--- 3.6-rc6.orig/mm/ksm.c 2012-09-18 15:38:08.000000000 -0700
+++ 3.6-rc6/mm/ksm.c 2012-09-18 16:39:50.882992906 -0700
@@ -1582,7 +1582,7 @@ struct page *ksm_does_need_to_copy(struc
SetPageSwapBacked(new_page);
__set_page_locked(new_page);
- if (page_evictable(new_page, vma))
+ if (!mlocked_vma_newpage(vma, new_page))
lru_cache_add_lru(new_page, LRU_ACTIVE_ANON);
else
add_page_to_unevictable_list(new_page);
--- 3.6-rc6.orig/mm/rmap.c 2012-09-18 15:38:08.000000000 -0700
+++ 3.6-rc6/mm/rmap.c 2012-09-18 16:39:50.882992906 -0700
@@ -1128,7 +1128,7 @@ void page_add_new_anon_rmap(struct page
else
__inc_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES);
__page_set_anon_rmap(page, vma, address, 1);
- if (page_evictable(page, vma))
+ if (!mlocked_vma_newpage(vma, page))
lru_cache_add_lru(page, LRU_ACTIVE_ANON);
else
add_page_to_unevictable_list(page);
--- 3.6-rc6.orig/mm/swap.c 2012-09-18 15:38:08.000000000 -0700
+++ 3.6-rc6/mm/swap.c 2012-09-18 16:39:50.882992906 -0700
@@ -742,7 +742,7 @@ void lru_add_page_tail(struct page *page
SetPageLRU(page_tail);
- if (page_evictable(page_tail, NULL)) {
+ if (page_evictable(page_tail)) {
if (PageActive(page)) {
SetPageActive(page_tail);
active = 1;
--- 3.6-rc6.orig/mm/vmscan.c 2012-09-18 15:38:08.000000000 -0700
+++ 3.6-rc6/mm/vmscan.c 2012-09-18 16:39:50.882992906 -0700
@@ -553,7 +553,7 @@ void putback_lru_page(struct page *page)
redo:
ClearPageUnevictable(page);
- if (page_evictable(page, NULL)) {
+ if (page_evictable(page)) {
/*
* For evictable pages, we can use the cache.
* In event of a race, worst case is we end up with an
@@ -587,7 +587,7 @@ redo:
* page is on unevictable list, it never be freed. To avoid that,
* check after we added it to the list, again.
*/
- if (lru == LRU_UNEVICTABLE && page_evictable(page, NULL)) {
+ if (lru == LRU_UNEVICTABLE && page_evictable(page)) {
if (!isolate_lru_page(page)) {
put_page(page);
goto redo;
@@ -707,7 +707,7 @@ static unsigned long shrink_page_list(st
sc->nr_scanned++;
- if (unlikely(!page_evictable(page, NULL)))
+ if (unlikely(!page_evictable(page)))
goto cull_mlocked;
if (!sc->may_unmap && page_mapped(page))
@@ -1186,7 +1186,7 @@ putback_inactive_pages(struct lruvec *lr
VM_BUG_ON(PageLRU(page));
list_del(&page->lru);
- if (unlikely(!page_evictable(page, NULL))) {
+ if (unlikely(!page_evictable(page))) {
spin_unlock_irq(&zone->lru_lock);
putback_lru_page(page);
spin_lock_irq(&zone->lru_lock);
@@ -1439,7 +1439,7 @@ static void shrink_active_list(unsigned
page = lru_to_page(&l_hold);
list_del(&page->lru);
- if (unlikely(!page_evictable(page, NULL))) {
+ if (unlikely(!page_evictable(page))) {
putback_lru_page(page);
continue;
}
@@ -3349,27 +3349,18 @@ int zone_reclaim(struct zone *zone, gfp_
/*
* page_evictable - test whether a page is evictable
* @page: the page to test
- * @vma: the VMA in which the page is or will be mapped, may be NULL
*
* Test whether page is evictable--i.e., should be placed on active/inactive
- * lists vs unevictable list. The vma argument is !NULL when called from the
- * fault path to determine how to instantate a new page.
+ * lists vs unevictable list.
*
* Reasons page might not be evictable:
* (1) page's mapping marked unevictable
* (2) page is part of an mlocked VMA
*
*/
-int page_evictable(struct page *page, struct vm_area_struct *vma)
+int page_evictable(struct page *page)
{
-
- if (mapping_unevictable(page_mapping(page)))
- return 0;
-
- if (PageMlocked(page) || (vma && mlocked_vma_newpage(vma, page)))
- return 0;
-
- return 1;
+ return !mapping_unevictable(page_mapping(page)) && !PageMlocked(page);
}
#ifdef CONFIG_SHMEM
@@ -3407,7 +3398,7 @@ void check_move_unevictable_pages(struct
if (!PageLRU(page) || !PageUnevictable(page))
continue;
- if (page_evictable(page, NULL)) {
+ if (page_evictable(page)) {
enum lru_list lru = page_lru_base_type(page);
VM_BUG_ON(PageActive(page));
--
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