Some fallout from the pagemap_lru_lock changes:
- lru_cache_del() is no longer used. Kill it.
- page_cache_release() almost never actually frees pages. So inline
page_cache_release() and move its rarely-called slow path into (the
misnamed) mm/swap.c
- update the locking comment in filemap.c. pagemap_lru_lock used to
be one of the outermost locks in the VM locking hierarchy. Now, we
never take any other locks while holding pagemap_lru_lock. So it
doesn't have any relationship with anything.
- put_page() now removes pages from the LRU on the final put. The
lock is interrupt save.
include/linux/mm.h | 7 ++++++-
include/linux/pagemap.h | 8 ++++++--
include/linux/swap.h | 2 --
kernel/ksyms.c | 2 +-
mm/filemap.c | 1 -
mm/page_alloc.c | 20 +-------------------
mm/swap.c | 31 ++++++++++++-------------------
mm/vmscan.c | 6 ++++++
8 files changed, 32 insertions(+), 45 deletions(-)
--- 2.5.31/mm/swap.c~lru-mopup Sun Aug 11 00:20:33 2002
+++ 2.5.31-akpm/mm/swap.c Sun Aug 11 00:21:01 2002
@@ -60,32 +60,25 @@ void lru_cache_add(struct page * page)
}
}
-/**
- * __lru_cache_del: remove a page from the page lists
- * @page: the page to add
- *
- * This function is for when the caller already holds
- * the pagemap_lru_lock.
+/*
+ * This path almost never happens - pages are normally freed via pagevecs.
*/
-void __lru_cache_del(struct page * page)
+void __page_cache_release(struct page *page)
{
- if (TestClearPageLRU(page)) {
+ BUG_ON(page_count(page) != 0);
+ if (PageLRU(page)) {
+ unsigned long flags;
+
+ spin_lock_irqsave(&_pagemap_lru_lock, flags);
+ if (!TestClearPageLRU(page))
+ BUG();
if (PageActive(page))
del_page_from_active_list(page);
else
del_page_from_inactive_list(page);
+ spin_unlock_irqrestore(&_pagemap_lru_lock, flags);
}
-}
-
-/**
- * lru_cache_del: remove a page from the page lists
- * @page: the page to remove
- */
-void lru_cache_del(struct page * page)
-{
- spin_lock_irq(&_pagemap_lru_lock);
- __lru_cache_del(page);
- spin_unlock_irq(&_pagemap_lru_lock);
+ __free_page(page);
}
/*
--- 2.5.31/include/linux/swap.h~lru-mopup Sun Aug 11 00:20:33 2002
+++ 2.5.31-akpm/include/linux/swap.h Sun Aug 11 00:21:01 2002
@@ -157,8 +157,6 @@ extern int FASTCALL(page_over_rsslimit(s
/* linux/mm/swap.c */
extern void FASTCALL(lru_cache_add(struct page *));
-extern void FASTCALL(__lru_cache_del(struct page *));
-extern void FASTCALL(lru_cache_del(struct page *));
extern void FASTCALL(activate_page(struct page *));
--- 2.5.31/mm/page_alloc.c~lru-mopup Sun Aug 11 00:20:33 2002
+++ 2.5.31-akpm/mm/page_alloc.c Sun Aug 11 00:21:01 2002
@@ -90,6 +90,7 @@ static void __free_pages_ok (struct page
KERNEL_STAT_ADD(pgfree, 1<<order);
+ BUG_ON(PageLRU(page));
BUG_ON(PagePrivate(page));
BUG_ON(page->mapping != NULL);
BUG_ON(PageLocked(page));
@@ -450,25 +451,6 @@ unsigned long get_zeroed_page(unsigned i
return 0;
}
-void page_cache_release(struct page *page)
-{
- /*
- * FIXME: this PageReserved test is really expensive
- */
- if (!PageReserved(page) && put_page_testzero(page)) {
- /*
- * This path almost never happens - pages are normally freed
- * via pagevecs.
- */
- struct pagevec pvec;
-
- page_cache_get(page);
- pvec.nr = 1;
- pvec.pages[0] = page;
- __pagevec_release(&pvec);
- }
-}
-
void __pagevec_free(struct pagevec *pvec)
{
int i = pagevec_count(pvec);
--- 2.5.31/include/linux/pagemap.h~lru-mopup Sun Aug 11 00:20:33 2002
+++ 2.5.31-akpm/include/linux/pagemap.h Sun Aug 11 00:20:33 2002
@@ -23,14 +23,18 @@
#define PAGE_CACHE_ALIGN(addr) (((addr)+PAGE_CACHE_SIZE-1)&PAGE_CACHE_MASK)
#define page_cache_get(x) get_page(x)
-extern void FASTCALL(page_cache_release(struct page *));
+
+static inline void page_cache_release(struct page *page)
+{
+ if (!PageReserved(page) && put_page_testzero(page))
+ __page_cache_release(page);
+}
static inline struct page *page_cache_alloc(struct address_space *x)
{
return alloc_pages(x->gfp_mask, 0);
}
-
typedef int filler_t(void *, struct page *);
extern struct page * find_get_page(struct address_space *mapping,
--- 2.5.31/kernel/ksyms.c~lru-mopup Sun Aug 11 00:20:33 2002
+++ 2.5.31-akpm/kernel/ksyms.c Sun Aug 11 00:20:33 2002
@@ -92,7 +92,7 @@ EXPORT_SYMBOL(__alloc_pages);
EXPORT_SYMBOL(alloc_pages_node);
EXPORT_SYMBOL(__get_free_pages);
EXPORT_SYMBOL(get_zeroed_page);
-EXPORT_SYMBOL(page_cache_release);
+EXPORT_SYMBOL(__page_cache_release);
EXPORT_SYMBOL(__free_pages);
EXPORT_SYMBOL(free_pages);
EXPORT_SYMBOL(num_physpages);
--- 2.5.31/mm/filemap.c~lru-mopup Sun Aug 11 00:20:33 2002
+++ 2.5.31-akpm/mm/filemap.c Sun Aug 11 00:21:01 2002
@@ -53,7 +53,6 @@
/*
* Lock ordering:
*
- * pagemap_lru_lock
* ->i_shared_lock (vmtruncate)
* ->private_lock (__free_pte->__set_page_dirty_buffers)
* ->swap_list_lock
--- 2.5.31/include/linux/mm.h~lru-mopup Sun Aug 11 00:20:33 2002
+++ 2.5.31-akpm/include/linux/mm.h Sun Aug 11 00:21:01 2002
@@ -194,11 +194,16 @@ struct page {
* routine so they can be sure the page doesn't go away from under them.
*/
#define get_page(p) atomic_inc(&(p)->count)
-#define put_page(p) __free_page(p)
#define __put_page(p) atomic_dec(&(p)->count)
#define put_page_testzero(p) atomic_dec_and_test(&(p)->count)
#define page_count(p) atomic_read(&(p)->count)
#define set_page_count(p,v) atomic_set(&(p)->count, v)
+extern void FASTCALL(__page_cache_release(struct page *));
+#define put_page(p) \
+ do { \
+ if (put_page_testzero(p)) \
+ __page_cache_release(p); \
+ } while (0)
/*
* Multiple processes may "see" the same page. E.g. for untouched
--- 2.5.31/mm/vmscan.c~lru-mopup Sun Aug 11 00:20:33 2002
+++ 2.5.31-akpm/mm/vmscan.c Sun Aug 11 00:21:01 2002
@@ -165,6 +165,12 @@ shrink_list(struct list_head *page_list,
pte_chain_unlock(page);
mapping = page->mapping;
+ /*
+ * FIXME: this is CPU-inefficient for shared mappings.
+ * try_to_unmap() will set the page dirty and ->vm_writeback
+ * will write it. So we're back to page-at-a-time writepage
+ * in LRU order.
+ */
if (PageDirty(page) && is_page_cache_freeable(page) &&
mapping && may_enter_fs) {
int (*writeback)(struct page *, int *);
.
-
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This archive was generated by hypermail 2b29 : Thu Aug 15 2002 - 22:00:23 EST