[patch 5/7] mm: spinlock tree_lock

npiggin
2008-06-05T09:43:05Z

[-- Attachment #1: mm-spinlock-tree_lock.patch --]
[-- Type: text/plain, Size: 12281 bytes --]

mapping->tree_lock has no read lockers. convert the lock from an rwlock
to a spinlock.

Signed-off-by: Nick Piggin <npiggin@suse.de>
---
Index: linux-2.6/fs/buffer.c
===================================================================
--- linux-2.6.orig/fs/buffer.c
+++ linux-2.6/fs/buffer.c
@@ -706,7 +706,7 @@ static int __set_page_dirty(struct page
if (TestSetPageDirty(page))
return 0;

- write_lock_irq(&mapping->tree_lock);
+ spin_lock_irq(&mapping->tree_lock);
if (page->mapping) { /* Race with truncate? */
WARN_ON_ONCE(warn && !PageUptodate(page));

@@ -719,7 +719,7 @@ static int __set_page_dirty(struct page
radix_tree_tag_set(&mapping->page_tree,
page_index(page), PAGECACHE_TAG_DIRTY);
}
- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);

return 1;
Index: linux-2.6/fs/inode.c
===================================================================
--- linux-2.6.orig/fs/inode.c
+++ linux-2.6/fs/inode.c
@@ -209,7 +209,7 @@ void inode_init_once(struct inode *inode
INIT_LIST_HEAD(&inode->i_dentry);
INIT_LIST_HEAD(&inode->i_devices);
INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
- rwlock_init(&inode->i_data.tree_lock);
+ spin_lock_init(&inode->i_data.tree_lock);
spin_lock_init(&inode->i_data.i_mmap_lock);
INIT_LIST_HEAD(&inode->i_data.private_list);
spin_lock_init(&inode->i_data.private_lock);
Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h
+++ linux-2.6/include/linux/fs.h
@@ -498,7 +498,7 @@ struct backing_dev_info;
struct address_space {
struct inode *host; /* owner: inode, block_device */
struct radix_tree_root page_tree; /* radix tree of all pages */
- rwlock_t tree_lock; /* and rwlock protecting it */
+ spinlock_t tree_lock; /* and lock protecting it */
unsigned int i_mmap_writable;/* count VM_SHARED mappings */
struct prio_tree_root i_mmap; /* tree of private and shared mappings */
struct list_head i_mmap_nonlinear;/*list VM_NONLINEAR mappings */
Index: linux-2.6/mm/filemap.c
===================================================================
--- linux-2.6.orig/mm/filemap.c
+++ linux-2.6/mm/filemap.c
@@ -112,7 +112,7 @@ generic_file_direct_IO(int rw, struct ki
/*
* Remove a page from the page cache and free it. Caller has to make
* sure the page is locked and that nobody else uses it - or that usage
- * is safe. The caller must hold a write_lock on the mapping's tree_lock.
+ * is safe. The caller must hold the mapping's tree_lock.
*/
void __remove_from_page_cache(struct page *page)
{
@@ -144,9 +144,9 @@ void remove_from_page_cache(struct page

BUG_ON(!PageLocked(page));

- write_lock_irq(&mapping->tree_lock);
+ spin_lock_irq(&mapping->tree_lock);
__remove_from_page_cache(page);
- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);
}

static int sync_page(void *word)
@@ -471,7 +471,7 @@ int add_to_page_cache(struct page *page,
page->mapping = mapping;
page->index = offset;

- write_lock_irq(&mapping->tree_lock);
+ spin_lock_irq(&mapping->tree_lock);
error = radix_tree_insert(&mapping->page_tree, offset, page);
if (likely(!error)) {
mapping->nrpages++;
@@ -483,7 +483,7 @@ int add_to_page_cache(struct page *page,
page_cache_release(page);
}

- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);
radix_tree_preload_end();
} else
mem_cgroup_uncharge_page(page);
Index: linux-2.6/mm/swap_state.c
===================================================================
--- linux-2.6.orig/mm/swap_state.c
+++ linux-2.6/mm/swap_state.c
@@ -39,7 +39,7 @@ static struct backing_dev_info swap_back

struct address_space swapper_space = {
.page_tree = RADIX_TREE_INIT(GFP_ATOMIC|__GFP_NOWARN),
- .tree_lock = __RW_LOCK_UNLOCKED(swapper_space.tree_lock),
+ .tree_lock = __SPIN_LOCK_UNLOCKED(swapper_space.tree_lock),
.a_ops = &swap_aops,
.i_mmap_nonlinear = LIST_HEAD_INIT(swapper_space.i_mmap_nonlinear),
.backing_dev_info = &swap_backing_dev_info,
@@ -80,7 +80,7 @@ int add_to_swap_cache(struct page *page,
SetPageSwapCache(page);
set_page_private(page, entry.val);

- write_lock_irq(&swapper_space.tree_lock);
+ spin_lock_irq(&swapper_space.tree_lock);
error = radix_tree_insert(&swapper_space.page_tree,
entry.val, page);
if (likely(!error)) {
@@ -88,7 +88,7 @@ int add_to_swap_cache(struct page *page,
__inc_zone_page_state(page, NR_FILE_PAGES);
INC_CACHE_INFO(add_total);
}
- write_unlock_irq(&swapper_space.tree_lock);
+ spin_unlock_irq(&swapper_space.tree_lock);
radix_tree_preload_end();

if (unlikely(error)) {
@@ -182,9 +182,9 @@ void delete_from_swap_cache(struct page

entry.val = page_private(page);

- write_lock_irq(&swapper_space.tree_lock);
+ spin_lock_irq(&swapper_space.tree_lock);
__delete_from_swap_cache(page);
- write_unlock_irq(&swapper_space.tree_lock);
+ spin_unlock_irq(&swapper_space.tree_lock);

swap_free(entry);
page_cache_release(page);
Index: linux-2.6/mm/swapfile.c
===================================================================
--- linux-2.6.orig/mm/swapfile.c
+++ linux-2.6/mm/swapfile.c
@@ -368,13 +368,13 @@ int remove_exclusive_swap_page(struct pa
retval = 0;
if (p->swap_map[swp_offset(entry)] == 1) {
/* Recheck the page count with the swapcache lock held.. */
- write_lock_irq(&swapper_space.tree_lock);
+ spin_lock_irq(&swapper_space.tree_lock);
if ((page_count(page) == 2) && !PageWriteback(page)) {
__delete_from_swap_cache(page);
SetPageDirty(page);
retval = 1;
}
- write_unlock_irq(&swapper_space.tree_lock);
+ spin_unlock_irq(&swapper_space.tree_lock);
}
spin_unlock(&swap_lock);

Index: linux-2.6/mm/truncate.c
===================================================================
--- linux-2.6.orig/mm/truncate.c
+++ linux-2.6/mm/truncate.c
@@ -349,18 +349,18 @@ invalidate_complete_page2(struct address
if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL))
return 0;

- write_lock_irq(&mapping->tree_lock);
+ spin_lock_irq(&mapping->tree_lock);
if (PageDirty(page))
goto failed;

BUG_ON(PagePrivate(page));
__remove_from_page_cache(page);
- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);
ClearPageUptodate(page);
page_cache_release(page); /* pagecache ref */
return 1;
failed:
- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);
return 0;
}

Index: linux-2.6/mm/vmscan.c
===================================================================
--- linux-2.6.orig/mm/vmscan.c
+++ linux-2.6/mm/vmscan.c
@@ -398,7 +398,7 @@ static int __remove_mapping(struct addre
BUG_ON(!PageLocked(page));
BUG_ON(mapping != page_mapping(page));

- write_lock_irq(&mapping->tree_lock);
+ spin_lock_irq(&mapping->tree_lock);
/*
* The non racy check for a busy page.
*
@@ -433,17 +433,17 @@ static int __remove_mapping(struct addre
if (PageSwapCache(page)) {
swp_entry_t swap = { .val = page_private(page) };
__delete_from_swap_cache(page);
- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);
swap_free(swap);
} else {
__remove_from_page_cache(page);
- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);
}

return 1;

cannot_free:
- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);
return 0;
}

Index: linux-2.6/mm/page-writeback.c
===================================================================
--- linux-2.6.orig/mm/page-writeback.c
+++ linux-2.6/mm/page-writeback.c
@@ -1081,7 +1081,7 @@ int __set_page_dirty_nobuffers(struct pa
if (!mapping)
return 1;

- write_lock_irq(&mapping->tree_lock);
+ spin_lock_irq(&mapping->tree_lock);
mapping2 = page_mapping(page);
if (mapping2) { /* Race with truncate? */
BUG_ON(mapping2 != mapping);
@@ -1095,7 +1095,7 @@ int __set_page_dirty_nobuffers(struct pa
radix_tree_tag_set(&mapping->page_tree,
page_index(page), PAGECACHE_TAG_DIRTY);
}
- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);
if (mapping->host) {
/* !PageAnon && !swapper_space */
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
@@ -1251,7 +1251,7 @@ int test_clear_page_writeback(struct pag
struct backing_dev_info *bdi = mapping->backing_dev_info;
unsigned long flags;

- write_lock_irqsave(&mapping->tree_lock, flags);
+ spin_lock_irqsave(&mapping->tree_lock, flags);
ret = TestClearPageWriteback(page);
if (ret) {
radix_tree_tag_clear(&mapping->page_tree,
@@ -1262,7 +1262,7 @@ int test_clear_page_writeback(struct pag
__bdi_writeout_inc(bdi);
}
}
- write_unlock_irqrestore(&mapping->tree_lock, flags);
+ spin_unlock_irqrestore(&mapping->tree_lock, flags);
} else {
ret = TestClearPageWriteback(page);
}
@@ -1280,7 +1280,7 @@ int test_set_page_writeback(struct page
struct backing_dev_info *bdi = mapping->backing_dev_info;
unsigned long flags;

- write_lock_irqsave(&mapping->tree_lock, flags);
+ spin_lock_irqsave(&mapping->tree_lock, flags);
ret = TestSetPageWriteback(page);
if (!ret) {
radix_tree_tag_set(&mapping->page_tree,
@@ -1293,7 +1293,7 @@ int test_set_page_writeback(struct page
radix_tree_tag_clear(&mapping->page_tree,
page_index(page),
PAGECACHE_TAG_DIRTY);
- write_unlock_irqrestore(&mapping->tree_lock, flags);
+ spin_unlock_irqrestore(&mapping->tree_lock, flags);
} else {
ret = TestSetPageWriteback(page);
}
Index: linux-2.6/include/asm-arm/cacheflush.h
===================================================================
--- linux-2.6.orig/include/asm-arm/cacheflush.h
+++ linux-2.6/include/asm-arm/cacheflush.h
@@ -421,9 +421,9 @@ static inline void flush_anon_page(struc
}

#define flush_dcache_mmap_lock(mapping) \
- write_lock_irq(&(mapping)->tree_lock)
+ spin_lock_irq(&(mapping)->tree_lock)
#define flush_dcache_mmap_unlock(mapping) \
- write_unlock_irq(&(mapping)->tree_lock)
+ spin_unlock_irq(&(mapping)->tree_lock)

#define flush_icache_user_range(vma,page,addr,len) \
flush_dcache_page(page)
Index: linux-2.6/include/asm-parisc/cacheflush.h
===================================================================
--- linux-2.6.orig/include/asm-parisc/cacheflush.h
+++ linux-2.6/include/asm-parisc/cacheflush.h
@@ -45,9 +45,9 @@ void flush_cache_mm(struct mm_struct *mm
extern void flush_dcache_page(struct page *page);

#define flush_dcache_mmap_lock(mapping) \
- write_lock_irq(&(mapping)->tree_lock)
+ spin_lock_irq(&(mapping)->tree_lock)
#define flush_dcache_mmap_unlock(mapping) \
- write_unlock_irq(&(mapping)->tree_lock)
+ spin_unlock_irq(&(mapping)->tree_lock)

#define flush_icache_page(vma,page) do { \
flush_kernel_dcache_page(page); \
Index: linux-2.6/mm/migrate.c
===================================================================
--- linux-2.6.orig/mm/migrate.c
+++ linux-2.6/mm/migrate.c
@@ -314,7 +314,7 @@ static int migrate_page_move_mapping(str
return 0;
}

- write_lock_irq(&mapping->tree_lock);
+ spin_lock_irq(&mapping->tree_lock);

pslot = radix_tree_lookup_slot(&mapping->page_tree,
page_index(page));
@@ -322,12 +322,12 @@ static int migrate_page_move_mapping(str
expected_count = 2 + !!PagePrivate(page);
if (page_count(page) != expected_count ||
(struct page *)radix_tree_deref_slot(pslot) != page) {
- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);
return -EAGAIN;
}

if (!page_freeze_refs(page, expected_count)) {
- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);
return -EAGAIN;
}

@@ -364,7 +364,7 @@ static int migrate_page_move_mapping(str
__dec_zone_page_state(page, NR_FILE_PAGES);
__inc_zone_page_state(newpage, NR_FILE_PAGES);

- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);

return 0;
}