[patch 1/4] mm: bdi: add separate writeback accounting capability

From: Miklos Szeredi
Date: Wed Mar 19 2008 - 20:23:10 EST

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From: Miklos Szeredi <mszeredi@xxxxxxx>

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@xxxxxxx>
---
fs/configfs/inode.c | 2 -
fs/hugetlbfs/inode.c | 2 -
fs/ocfs2/dlm/dlmfs.c | 2 -
fs/ramfs/inode.c | 2 -
fs/sysfs/inode.c | 2 -
include/linux/backing-dev.h | 77 ++++++++++++++++++++++++++++++++------------
kernel/cgroup.c | 2 -
mm/page-writeback.c | 4 +-
mm/shmem.c | 2 -
mm/swap_state.c | 2 -
10 files changed, 67 insertions(+), 30 deletions(-)

Index: linux/fs/configfs/inode.c
===================================================================
--- linux.orig/fs/configfs/inode.c 2008-03-18 19:27:43.000000000 +0100
+++ linux/fs/configfs/inode.c 2008-03-18 19:38:45.000000000 +0100
@@ -47,7 +47,7 @@ static const struct address_space_operat

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 ={
Index: linux/fs/hugetlbfs/inode.c
===================================================================
--- linux.orig/fs/hugetlbfs/inode.c 2008-03-18 19:27:43.000000000 +0100
+++ linux/fs/hugetlbfs/inode.c 2008-03-18 19:38:45.000000000 +0100
@@ -45,7 +45,7 @@ static const struct inode_operations hug

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;
Index: linux/fs/ocfs2/dlm/dlmfs.c
===================================================================
--- linux.orig/fs/ocfs2/dlm/dlmfs.c 2008-03-18 19:27:43.000000000 +0100
+++ linux/fs/ocfs2/dlm/dlmfs.c 2008-03-18 19:38:45.000000000 +0100
@@ -327,7 +327,7 @@ clear_fields:

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)
Index: linux/fs/ramfs/inode.c
===================================================================
--- linux.orig/fs/ramfs/inode.c 2008-03-18 19:27:43.000000000 +0100
+++ linux/fs/ramfs/inode.c 2008-03-18 19:38:45.000000000 +0100
@@ -44,7 +44,7 @@ static const struct inode_operations ram

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,
};
Index: linux/fs/sysfs/inode.c
===================================================================
--- linux.orig/fs/sysfs/inode.c 2008-03-18 19:27:43.000000000 +0100
+++ linux/fs/sysfs/inode.c 2008-03-18 19:38:45.000000000 +0100
@@ -30,7 +30,7 @@ static const struct address_space_operat

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 ={
Index: linux/include/linux/backing-dev.h
===================================================================
--- linux.orig/include/linux/backing-dev.h 2008-03-18 19:27:43.000000000 +0100
+++ linux/include/linux/backing-dev.h 2008-03-18 19:38:45.000000000 +0100
@@ -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;
@@ -153,22 +154,43 @@ int bdi_set_max_ratio(struct backing_dev

/*
* 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 || \
@@ -208,17 +230,32 @@ void clear_bdi_congested(struct backing_
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 */
Index: linux/kernel/cgroup.c
===================================================================
--- linux.orig/kernel/cgroup.c 2008-03-18 19:27:43.000000000 +0100
+++ linux/kernel/cgroup.c 2008-03-18 19:38:45.000000000 +0100
@@ -551,7 +551,7 @@ static struct inode_operations cgroup_di
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)
Index: linux/mm/page-writeback.c
===================================================================
--- linux.orig/mm/page-writeback.c 2008-03-18 19:38:34.000000000 +0100
+++ linux/mm/page-writeback.c 2008-03-18 19:38:45.000000000 +0100
@@ -1257,7 +1257,7 @@ int test_clear_page_writeback(struct pag
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);
}
@@ -1286,7 +1286,7 @@ int test_set_page_writeback(struct page
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))
Index: linux/mm/shmem.c
===================================================================
--- linux.orig/mm/shmem.c 2008-03-18 19:27:43.000000000 +0100
+++ linux/mm/shmem.c 2008-03-18 19:38:45.000000000 +0100
@@ -201,7 +201,7 @@ static struct vm_operations_struct shmem

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,
};

Index: linux/mm/swap_state.c
===================================================================
--- linux.orig/mm/swap_state.c 2008-03-18 19:27:43.000000000 +0100
+++ linux/mm/swap_state.c 2008-03-18 19:38:45.000000000 +0100
@@ -33,7 +33,7 @@ static const struct address_space_operat
};

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,
};

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Next message: Miklos Szeredi: "Re: [patch 4/8] mm: allow not updating BDI stats inend_page_writeback()"
Previous message: Miklos Szeredi: "[patch 4/4] fuse: support writable mmap fix"
In reply to: Miklos Szeredi: "[patch 4/4] fuse: support writable mmap fix"
Next in thread: Miklos Szeredi: "[patch 3/4] mm: document missing fields for /proc/meminfo"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]