[PATCH 4/9] clockpro-use-once.patch

Peter Zijlstra
2005-12-30T22:43:40Z

From: Rik van Riel <riel@surriel.com>

Simplify the use-once code. I have not benchmarked this change yet,
but I expect it to have little impact on most workloads. It gets rid
of some magic code though, which is nice.

Modified to work with this CLOCK-Pro implementation.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

include/linux/mm_page_replace.h | 14 --------------
mm/filemap.c | 11 ++---------
mm/shmem.c | 6 +-----
mm/swap.c | 27 +--------------------------
mm/swapfile.c | 4 ++--
mm/vmscan.c | 25 ++-----------------------
6 files changed, 8 insertions(+), 79 deletions(-)

Index: linux-2.6-git/mm/filemap.c
===================================================================
--- linux-2.6-git.orig/mm/filemap.c
+++ linux-2.6-git/mm/filemap.c
@@ -387,6 +387,7 @@ int add_to_page_cache(struct page *page,
if (!error) {
page_cache_get(page);
SetPageLocked(page);
+ SetPageTest(page);
page->mapping = mapping;
page->index = offset;
mapping->nrpages++;
@@ -726,7 +727,6 @@ void do_generic_mapping_read(struct addr
unsigned long offset;
unsigned long last_index;
unsigned long next_index;
- unsigned long prev_index;
loff_t isize;
struct page *cached_page;
int error;
@@ -735,7 +735,6 @@ void do_generic_mapping_read(struct addr
cached_page = NULL;
index = *ppos >> PAGE_CACHE_SHIFT;
next_index = index;
- prev_index = ra.prev_page;
last_index = (*ppos + desc->count + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
offset = *ppos & ~PAGE_CACHE_MASK;

@@ -782,13 +781,7 @@ page_ok:
if (mapping_writably_mapped(mapping))
flush_dcache_page(page);

- /*
- * When (part of) the same page is read multiple times
- * in succession, only mark it as accessed the first time.
- */
- if (prev_index != index)
- mark_page_accessed(page);
- prev_index = index;
+ mark_page_accessed(page);

/*
* Ok, we have the page, and it's up-to-date, so
Index: linux-2.6-git/mm/swap.c
===================================================================
--- linux-2.6-git.orig/mm/swap.c
+++ linux-2.6-git/mm/swap.c
@@ -90,37 +90,12 @@ int rotate_reclaimable_page(struct page
}

/*
- * FIXME: speed this up?
- */
-void fastcall activate_page(struct page *page)
-{
- struct zone *zone = page_zone(page);
-
- spin_lock_irq(&zone->lru_lock);
- if (PageLRU(page) && !PageActive(page)) {
- del_page_from_inactive_list(zone, page);
- SetPageActive(page);
- add_page_to_active_list(zone, page);
- inc_page_state(pgactivate);
- }
- spin_unlock_irq(&zone->lru_lock);
-}
-
-/*
* Mark a page as having seen activity.
- *
- * inactive,unreferenced -> inactive,referenced
- * inactive,referenced -> active,unreferenced
- * active,unreferenced -> active,referenced
*/
void fastcall mark_page_accessed(struct page *page)
{
- if (!PageActive(page) && PageReferenced(page) && PageLRU(page)) {
- activate_page(page);
- ClearPageReferenced(page);
- } else if (!PageReferenced(page)) {
+ if (!PageReferenced(page))
SetPageReferenced(page);
- }
}

EXPORT_SYMBOL(mark_page_accessed);
Index: linux-2.6-git/mm/swapfile.c
===================================================================
--- linux-2.6-git.orig/mm/swapfile.c
+++ linux-2.6-git/mm/swapfile.c
@@ -421,7 +421,7 @@ static void unuse_pte(struct vm_area_str
* Move the page to the active list so it is not
* immediately swapped out again after swapon.
*/
- activate_page(page);
+ mark_page_accessed(page);
}

static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
@@ -523,7 +523,7 @@ static int unuse_mm(struct mm_struct *mm
* Activate page so shrink_cache is unlikely to unmap its
* ptes while lock is dropped, so swapoff can make progress.
*/
- activate_page(page);
+ mark_page_accessed(page);
unlock_page(page);
down_read(&mm->mmap_sem);
lock_page(page);
Index: linux-2.6-git/mm/vmscan.c
===================================================================
--- linux-2.6-git.orig/mm/vmscan.c
+++ linux-2.6-git/mm/vmscan.c
@@ -219,27 +219,6 @@ static int shrink_slab(unsigned long sca
return ret;
}

-/* Called without lock on whether page is mapped, so answer is unstable */
-static inline int page_mapping_inuse(struct page *page)
-{
- struct address_space *mapping;
-
- /* Page is in somebody's page tables. */
- if (page_mapped(page))
- return 1;
-
- /* Be more reluctant to reclaim swapcache than pagecache */
- if (PageSwapCache(page))
- return 1;
-
- mapping = page_mapping(page);
- if (!mapping)
- return 0;
-
- /* File is mmap'd by somebody? */
- return mapping_mapped(mapping);
-}
-
static inline int is_page_cache_freeable(struct page *page)
{
return page_count(page) - !!PagePrivate(page) == 2;
@@ -374,8 +353,8 @@ static try_pageout_t try_pageout(struct
goto keep_locked;

referenced = page_referenced(page, 1);
- /* In active use or really unfreeable? Activate it. */
- if (referenced && page_mapping_inuse(page))
+
+ if (referenced)
goto activate_locked;

#ifdef CONFIG_SWAP
Index: linux-2.6-git/mm/shmem.c
===================================================================
--- linux-2.6-git.orig/mm/shmem.c
+++ linux-2.6-git/mm/shmem.c
@@ -1499,11 +1499,7 @@ static void do_shmem_file_read(struct fi
*/
if (mapping_writably_mapped(mapping))
flush_dcache_page(page);
- /*
- * Mark the page accessed if we read the beginning.
- */
- if (!offset)
- mark_page_accessed(page);
+ mark_page_accessed(page);
} else {
page = ZERO_PAGE(0);
page_cache_get(page);
Index: linux-2.6-git/include/linux/mm_page_replace.h
===================================================================
--- linux-2.6-git.orig/include/linux/mm_page_replace.h
+++ linux-2.6-git/include/linux/mm_page_replace.h
@@ -67,20 +67,6 @@ add_page_to_active_list(struct zone *zon
}

static inline void
-del_page_from_active_list(struct zone *zone, struct page *page)
-{
- list_del(&page->lru);
- zone->nr_active--;
-}
-
-static inline void
-del_page_from_inactive_list(struct zone *zone, struct page *page)
-{
- list_del(&page->lru);
- zone->nr_inactive--;
-}
-
-static inline void
del_page_from_lru(struct zone *zone, struct page *page)
{
list_del(&page->lru);