Patch from Dave McCracken <dmccr@us.ibm.com>
Convert page.pte.mapcount to an int, move its manipulation inside
pte_chain_lock().
25-akpm/include/linux/mm.h | 2 +-
25-akpm/mm/rmap.c | 27 +++++++++++++++------------
2 files changed, 16 insertions(+), 13 deletions(-)
diff -puN include/linux/mm.h~objrmap-atomic_t-fix include/linux/mm.h
--- 25/include/linux/mm.h~objrmap-atomic_t-fix Tue Mar 4 13:13:48 2003
+++ 25-akpm/include/linux/mm.h Tue Mar 4 13:13:48 2003
@@ -172,7 +172,7 @@ struct page {
struct pte_chain *chain;/* Reverse pte mapping pointer.
* protected by PG_chainlock */
pte_addr_t direct;
- atomic_t mapcount;
+ int mapcount;
} pte;
unsigned long private; /* mapping-private opaque data */
diff -puN mm/rmap.c~objrmap-atomic_t-fix mm/rmap.c
--- 25/mm/rmap.c~objrmap-atomic_t-fix Tue Mar 4 13:13:48 2003
+++ 25-akpm/mm/rmap.c Tue Mar 4 13:13:48 2003
@@ -144,7 +144,7 @@ page_referenced_obj(struct page *page)
struct vm_area_struct *vma;
int referenced = 0;
- if (atomic_read(&page->pte.mapcount) == 0)
+ if (!page->pte.mapcount)
return 0;
if (!mapping)
@@ -243,19 +243,20 @@ page_add_rmap(struct page *page, pte_t *
if (!pfn_valid(page_to_pfn(page)) || PageReserved(page))
return pte_chain;
+ pte_chain_lock(page);
+
if (!PageAnon(page)) {
if (!page->mapping)
BUG();
if (PageSwapCache(page))
BUG();
- if (atomic_read(&page->pte.mapcount) == 0)
+ if (!page->pte.mapcount)
inc_page_state(nr_mapped);
- atomic_inc(&page->pte.mapcount);
+ page->pte.mapcount++;
+ pte_chain_unlock(page);
return pte_chain;
}
- pte_chain_lock(page);
-
#ifdef DEBUG_RMAP
/*
* This stuff needs help to get up to highmem speed.
@@ -342,20 +343,22 @@ void page_remove_rmap(struct page * page
if (!page_mapped(page))
return; /* remap_page_range() from a driver? */
+ pte_chain_lock(page);
+
if (!PageAnon(page)) {
if (!page->mapping)
BUG();
if (PageSwapCache(page))
BUG();
- if (atomic_read(&page->pte.mapcount) == 0)
+ if (!page->pte.mapcount)
BUG();
- if (atomic_dec_and_test(&page->pte.mapcount))
+ page->pte.mapcount--;
+ if (!page->pte.mapcount)
dec_page_state(nr_mapped);
+ pte_chain_unlock(page);
return;
}
- pte_chain_lock(page);
-
if (PageDirect(page)) {
if (page->pte.direct == pte_paddr) {
page->pte.direct = 0;
@@ -471,11 +474,11 @@ try_to_unmap_obj_one(struct vm_area_stru
if (pte_dirty(pteval))
set_page_dirty(page);
- if (atomic_read(&page->pte.mapcount) == 0)
+ if (!page->pte.mapcount)
BUG();
mm->rss--;
- atomic_dec(&page->pte.mapcount);
+ page->pte.mapcount--;
page_cache_release(page);
out_unmap:
@@ -516,7 +519,7 @@ try_to_unmap_obj(struct page *page)
goto out;
}
- if (atomic_read(&page->pte.mapcount) != 0)
+ if (page->pte.mapcount)
BUG();
out:
_