mm: bdi: add separate writeback accounting capability

Add a new BDI capability flag: BDI_CAP_NO_ACCT_WB. If this flag is set, then don't update the per-bdi writeback stats from test_set_page_writeback() and test_clear_page_writeback(). Misc cleanups: - convert bdi_cap_writeback_dirty() and friends to static inline functions - create a flag that includes all three dirty/writeback related flags, since almst all users will want to have them toghether Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: bdi: add separate writeback accounting capability
Add a new BDI capability flag: BDI_CAP_NO_ACCT_WB. If this flag is set, then don't update the per-bdi writeback stats from test_set_page_writeback() and test_clear_page_writeback(). Misc cleanups: - convert bdi_cap_writeback_dirty() and friends to static inline functions - create a flag that includes all three dirty/writeback related flags, since almst all users will want to have them toghether Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Miklos Szeredi · Linus Torvalds
1 parent 76f1418b48
Showing 10 changed files with 67 additions and 30 deletions Side-by-side Diff
fs/configfs/inode.c
fs/hugetlbfs/inode.c
fs/ocfs2/dlm/dlmfs.c
fs/ramfs/inode.c
fs/sysfs/inode.c
include/linux/backing-dev.h
kernel/cgroup.c
mm/page-writeback.c
mm/shmem.c
mm/swap_state.c
@@ -47,7 +47,7 @@
  
 static struct backing_dev_info configfs_backing_dev_info = {
 	.ra_pages	= 0,	/* No readahead */
-	.capabilities	= BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK,
 };
  
 static const struct inode_operations configfs_inode_operations ={
@@ -45,7 +45,7 @@
  
 static struct backing_dev_info hugetlbfs_backing_dev_info = {
 	.ra_pages	= 0,	/* No readahead */
-	.capabilities	= BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK,
 };
  
 int sysctl_hugetlb_shm_group;
@@ -327,7 +327,7 @@
  
 static struct backing_dev_info dlmfs_backing_dev_info = {
 	.ra_pages	= 0,	/* No readahead */
-	.capabilities	= BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK,
 };
  
 static struct inode *dlmfs_get_root_inode(struct super_block *sb)
@@ -44,7 +44,7 @@
  
 static struct backing_dev_info ramfs_backing_dev_info = {
 	.ra_pages	= 0,	/* No readahead */
-	.capabilities	= BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK |
+	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK |
 			  BDI_CAP_MAP_DIRECT | BDI_CAP_MAP_COPY |
 			  BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP,
 };
@@ -30,7 +30,7 @@
  
 static struct backing_dev_info sysfs_backing_dev_info = {
 	.ra_pages	= 0,	/* No readahead */
-	.capabilities	= BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK,
 };
  
 static const struct inode_operations sysfs_inode_operations ={
@@ -12,6 +12,7 @@
 #include <linux/log2.h>
 #include <linux/proportions.h>
 #include <linux/kernel.h>
+#include <linux/fs.h>
 #include <asm/atomic.h>
  
 struct page;
  
  
@@ -151,22 +152,43 @@
  
 /*
  * Flags in backing_dev_info::capability
- * - The first two flags control whether dirty pages will contribute to the
- *   VM's accounting and whether writepages() should be called for dirty pages
- *   (something that would not, for example, be appropriate for ramfs)
- * - These flags let !MMU mmap() govern direct device mapping vs immediate
- *   copying more easily for MAP_PRIVATE, especially for ROM filesystems
+ *
+ * The first three flags control whether dirty pages will contribute to the
+ * VM's accounting and whether writepages() should be called for dirty pages
+ * (something that would not, for example, be appropriate for ramfs)
+ *
+ * WARNING: these flags are closely related and should not normally be
+ * used separately.  The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these
+ * three flags into a single convenience macro.
+ *
+ * BDI_CAP_NO_ACCT_DIRTY:  Dirty pages shouldn't contribute to accounting
+ * BDI_CAP_NO_WRITEBACK:   Don't write pages back
+ * BDI_CAP_NO_ACCT_WB:     Don't automatically account writeback pages
+ *
+ * These flags let !MMU mmap() govern direct device mapping vs immediate
+ * copying more easily for MAP_PRIVATE, especially for ROM filesystems.
+ *
+ * BDI_CAP_MAP_COPY:       Copy can be mapped (MAP_PRIVATE)
+ * BDI_CAP_MAP_DIRECT:     Can be mapped directly (MAP_SHARED)
+ * BDI_CAP_READ_MAP:       Can be mapped for reading
+ * BDI_CAP_WRITE_MAP:      Can be mapped for writing
+ * BDI_CAP_EXEC_MAP:       Can be mapped for execution
  */
-#define BDI_CAP_NO_ACCT_DIRTY	0x00000001	/* Dirty pages shouldn't contribute to accounting */
-#define BDI_CAP_NO_WRITEBACK	0x00000002	/* Don't write pages back */
-#define BDI_CAP_MAP_COPY	0x00000004	/* Copy can be mapped (MAP_PRIVATE) */
-#define BDI_CAP_MAP_DIRECT	0x00000008	/* Can be mapped directly (MAP_SHARED) */
-#define BDI_CAP_READ_MAP	0x00000010	/* Can be mapped for reading */
-#define BDI_CAP_WRITE_MAP	0x00000020	/* Can be mapped for writing */
-#define BDI_CAP_EXEC_MAP	0x00000040	/* Can be mapped for execution */
+#define BDI_CAP_NO_ACCT_DIRTY	0x00000001
+#define BDI_CAP_NO_WRITEBACK	0x00000002
+#define BDI_CAP_MAP_COPY	0x00000004
+#define BDI_CAP_MAP_DIRECT	0x00000008
+#define BDI_CAP_READ_MAP	0x00000010
+#define BDI_CAP_WRITE_MAP	0x00000020
+#define BDI_CAP_EXEC_MAP	0x00000040
+#define BDI_CAP_NO_ACCT_WB	0x00000080
+
 #define BDI_CAP_VMFLAGS \
 	(BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP)
  
+#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
+	(BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB)
+
 #if defined(VM_MAYREAD) && \
 	(BDI_CAP_READ_MAP != VM_MAYREAD || \
 	 BDI_CAP_WRITE_MAP != VM_MAYWRITE || \
  
  
  
  
@@ -206,18 +228,33 @@
 void set_bdi_congested(struct backing_dev_info *bdi, int rw);
 long congestion_wait(int rw, long timeout);
  
-#define bdi_cap_writeback_dirty(bdi) \
-	(!((bdi)->capabilities & BDI_CAP_NO_WRITEBACK))
  
-#define bdi_cap_account_dirty(bdi) \
-	(!((bdi)->capabilities & BDI_CAP_NO_ACCT_DIRTY))
+static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
+{
+	return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
+}
  
-#define mapping_cap_writeback_dirty(mapping) \
-	bdi_cap_writeback_dirty((mapping)->backing_dev_info)
+static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
+{
+	return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
+}
  
-#define mapping_cap_account_dirty(mapping) \
-	bdi_cap_account_dirty((mapping)->backing_dev_info)
+static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
+{
+	/* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
+	return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB |
+				      BDI_CAP_NO_WRITEBACK));
+}
  
+static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
+{
+	return bdi_cap_writeback_dirty(mapping->backing_dev_info);
+}
+
+static inline bool mapping_cap_account_dirty(struct address_space *mapping)
+{
+	return bdi_cap_account_dirty(mapping->backing_dev_info);
+}
  
 #endif		/* _LINUX_BACKING_DEV_H */
@@ -575,7 +575,7 @@
 static struct file_operations proc_cgroupstats_operations;
  
 static struct backing_dev_info cgroup_backing_dev_info = {
-	.capabilities	= BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK,
 };
  
 static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb)
@@ -1246,7 +1246,7 @@
 			radix_tree_tag_clear(&mapping->page_tree,
 						page_index(page),
 						PAGECACHE_TAG_WRITEBACK);
-			if (bdi_cap_writeback_dirty(bdi)) {
+			if (bdi_cap_account_writeback(bdi)) {
 				__dec_bdi_stat(bdi, BDI_WRITEBACK);
 				__bdi_writeout_inc(bdi);
 			}
@@ -1275,7 +1275,7 @@
 			radix_tree_tag_set(&mapping->page_tree,
 						page_index(page),
 						PAGECACHE_TAG_WRITEBACK);
-			if (bdi_cap_writeback_dirty(bdi))
+			if (bdi_cap_account_writeback(bdi))
 				__inc_bdi_stat(bdi, BDI_WRITEBACK);
 		}
 		if (!PageDirty(page))
@@ -201,7 +201,7 @@
  
 static struct backing_dev_info shmem_backing_dev_info  __read_mostly = {
 	.ra_pages	= 0,	/* No readahead */
-	.capabilities	= BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK,
 	.unplug_io_fn	= default_unplug_io_fn,
 };
  
@@ -33,7 +33,7 @@
 };
  
 static struct backing_dev_info swap_backing_dev_info = {
-	.capabilities	= BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK,
 	.unplug_io_fn	= swap_unplug_io_fn,
 };
...	...	@@ -47,7 +47,7 @@
47	47
48	48	static struct backing_dev_info configfs_backing_dev_info = {
49	49	.ra_pages = 0, /* No readahead */
50		- .capabilities = BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_WRITEBACK,
	50	+ .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
51	51	};
52	52
53	53	static const struct inode_operations configfs_inode_operations ={
...	...	@@ -45,7 +45,7 @@
45	45
46	46	static struct backing_dev_info hugetlbfs_backing_dev_info = {
47	47	.ra_pages = 0, /* No readahead */
48		- .capabilities = BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_WRITEBACK,
	48	+ .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
49	49	};
50	50
51	51	int sysctl_hugetlb_shm_group;
...	...	@@ -327,7 +327,7 @@
327	327
328	328	static struct backing_dev_info dlmfs_backing_dev_info = {
329	329	.ra_pages = 0, /* No readahead */
330		- .capabilities = BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_WRITEBACK,
	330	+ .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
331	331	};
332	332
333	333	static struct inode dlmfs_get_root_inode(struct super_block sb)
...	...	@@ -44,7 +44,7 @@
44	44
45	45	static struct backing_dev_info ramfs_backing_dev_info = {
46	46	.ra_pages = 0, /* No readahead */
47		- .capabilities = BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_WRITEBACK \|
	47	+ .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK \|
48	48	BDI_CAP_MAP_DIRECT \| BDI_CAP_MAP_COPY \|
49	49	BDI_CAP_READ_MAP \| BDI_CAP_WRITE_MAP \| BDI_CAP_EXEC_MAP,
50	50	};
...	...	@@ -30,7 +30,7 @@
30	30
31	31	static struct backing_dev_info sysfs_backing_dev_info = {
32	32	.ra_pages = 0, /* No readahead */
33		- .capabilities = BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_WRITEBACK,
	33	+ .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
34	34	};
35	35
36	36	static const struct inode_operations sysfs_inode_operations ={
...	...	@@ -12,6 +12,7 @@
12	12	#include <linux/log2.h>
13	13	#include <linux/proportions.h>
14	14	#include <linux/kernel.h>
	15	+#include <linux/fs.h>
15	16	#include <asm/atomic.h>
16	17
17	18	struct page;
18	19
19	20
...	...	@@ -151,22 +152,43 @@
151	152
152	153	/*
153	154	* Flags in backing_dev_info::capability
154		- * - The first two flags control whether dirty pages will contribute to the
155		- * VM's accounting and whether writepages() should be called for dirty pages
156		- * (something that would not, for example, be appropriate for ramfs)
157		- * - These flags let !MMU mmap() govern direct device mapping vs immediate
158		- * copying more easily for MAP_PRIVATE, especially for ROM filesystems
	155	+ *
	156	+ * The first three flags control whether dirty pages will contribute to the
	157	+ * VM's accounting and whether writepages() should be called for dirty pages
	158	+ * (something that would not, for example, be appropriate for ramfs)
	159	+ *
	160	+ * WARNING: these flags are closely related and should not normally be
	161	+ * used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these
	162	+ * three flags into a single convenience macro.
	163	+ *
	164	+ * BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting
	165	+ * BDI_CAP_NO_WRITEBACK: Don't write pages back
	166	+ * BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages
	167	+ *
	168	+ * These flags let !MMU mmap() govern direct device mapping vs immediate
	169	+ * copying more easily for MAP_PRIVATE, especially for ROM filesystems.
	170	+ *
	171	+ * BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE)
	172	+ * BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED)
	173	+ * BDI_CAP_READ_MAP: Can be mapped for reading
	174	+ * BDI_CAP_WRITE_MAP: Can be mapped for writing
	175	+ * BDI_CAP_EXEC_MAP: Can be mapped for execution
159	176	*/
160		-#define BDI_CAP_NO_ACCT_DIRTY 0x00000001 /* Dirty pages shouldn't contribute to accounting */
161		-#define BDI_CAP_NO_WRITEBACK 0x00000002 /* Don't write pages back */
162		-#define BDI_CAP_MAP_COPY 0x00000004 /* Copy can be mapped (MAP_PRIVATE) */
163		-#define BDI_CAP_MAP_DIRECT 0x00000008 /* Can be mapped directly (MAP_SHARED) */
164		-#define BDI_CAP_READ_MAP 0x00000010 /* Can be mapped for reading */
165		-#define BDI_CAP_WRITE_MAP 0x00000020 /* Can be mapped for writing */
166		-#define BDI_CAP_EXEC_MAP 0x00000040 /* Can be mapped for execution */
	177	+#define BDI_CAP_NO_ACCT_DIRTY 0x00000001
	178	+#define BDI_CAP_NO_WRITEBACK 0x00000002
	179	+#define BDI_CAP_MAP_COPY 0x00000004
	180	+#define BDI_CAP_MAP_DIRECT 0x00000008
	181	+#define BDI_CAP_READ_MAP 0x00000010
	182	+#define BDI_CAP_WRITE_MAP 0x00000020
	183	+#define BDI_CAP_EXEC_MAP 0x00000040
	184	+#define BDI_CAP_NO_ACCT_WB 0x00000080
	185	+
167	186	#define BDI_CAP_VMFLAGS \
168	187	(BDI_CAP_READ_MAP \| BDI_CAP_WRITE_MAP \| BDI_CAP_EXEC_MAP)
169	188
	189	+#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
	190	+ (BDI_CAP_NO_WRITEBACK \| BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_ACCT_WB)
	191	+
170	192	#if defined(VM_MAYREAD) && \
171	193	(BDI_CAP_READ_MAP != VM_MAYREAD \|\| \
172	194	BDI_CAP_WRITE_MAP != VM_MAYWRITE \|\| \
173	195
174	196
175	197
176	198
...	...	@@ -206,18 +228,33 @@
206	228	void set_bdi_congested(struct backing_dev_info *bdi, int rw);
207	229	long congestion_wait(int rw, long timeout);
208	230
209		-#define bdi_cap_writeback_dirty(bdi) \
210		- (!((bdi)->capabilities & BDI_CAP_NO_WRITEBACK))
211	231
212		-#define bdi_cap_account_dirty(bdi) \
213		- (!((bdi)->capabilities & BDI_CAP_NO_ACCT_DIRTY))
	232	+static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
	233	+{
	234	+ return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
	235	+}
214	236
215		-#define mapping_cap_writeback_dirty(mapping) \
216		- bdi_cap_writeback_dirty((mapping)->backing_dev_info)
	237	+static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
	238	+{
	239	+ return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
	240	+}
217	241
218		-#define mapping_cap_account_dirty(mapping) \
219		- bdi_cap_account_dirty((mapping)->backing_dev_info)
	242	+static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
	243	+{
	244	+ /* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
	245	+ return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB \|
	246	+ BDI_CAP_NO_WRITEBACK));
	247	+}
220	248
	249	+static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
	250	+{
	251	+ return bdi_cap_writeback_dirty(mapping->backing_dev_info);
	252	+}
	253	+
	254	+static inline bool mapping_cap_account_dirty(struct address_space *mapping)
	255	+{
	256	+ return bdi_cap_account_dirty(mapping->backing_dev_info);
	257	+}
221	258
222	259	#endif /* _LINUX_BACKING_DEV_H */
...	...	@@ -575,7 +575,7 @@
575	575	static struct file_operations proc_cgroupstats_operations;
576	576
577	577	static struct backing_dev_info cgroup_backing_dev_info = {
578		- .capabilities = BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_WRITEBACK,
	578	+ .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
579	579	};
580	580
581	581	static struct inode cgroup_new_inode(mode_t mode, struct super_block sb)
...	...	@@ -1246,7 +1246,7 @@
1246	1246	radix_tree_tag_clear(&mapping->page_tree,
1247	1247	page_index(page),
1248	1248	PAGECACHE_TAG_WRITEBACK);
1249		- if (bdi_cap_writeback_dirty(bdi)) {
	1249	+ if (bdi_cap_account_writeback(bdi)) {
1250	1250	__dec_bdi_stat(bdi, BDI_WRITEBACK);
1251	1251	__bdi_writeout_inc(bdi);
1252	1252	}
...	...	@@ -1275,7 +1275,7 @@
1275	1275	radix_tree_tag_set(&mapping->page_tree,
1276	1276	page_index(page),
1277	1277	PAGECACHE_TAG_WRITEBACK);
1278		- if (bdi_cap_writeback_dirty(bdi))
	1278	+ if (bdi_cap_account_writeback(bdi))
1279	1279	__inc_bdi_stat(bdi, BDI_WRITEBACK);
1280	1280	}
1281	1281	if (!PageDirty(page))
...	...	@@ -201,7 +201,7 @@
201	201
202	202	static struct backing_dev_info shmem_backing_dev_info __read_mostly = {
203	203	.ra_pages = 0, /* No readahead */
204		- .capabilities = BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_WRITEBACK,
	204	+ .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
205	205	.unplug_io_fn = default_unplug_io_fn,
206	206	};
207	207
...	...	@@ -33,7 +33,7 @@
33	33	};
34	34
35	35	static struct backing_dev_info swap_backing_dev_info = {
36		- .capabilities = BDI_CAP_NO_ACCT_DIRTY \| BDI_CAP_NO_WRITEBACK,
	36	+ .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
37	37	.unplug_io_fn = swap_unplug_io_fn,
38	38	};
39	39