From: Miklos Szeredi 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 --- Index: linux/fs/configfs/inode.c =================================================================== Signed-off-by: Andrew Morton --- 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(-) diff -puN fs/configfs/inode.c~mm-bdi-add-separate-writeback-accounting-capability fs/configfs/inode.c --- a/fs/configfs/inode.c~mm-bdi-add-separate-writeback-accounting-capability +++ a/fs/configfs/inode.c @@ -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 ={ diff -puN fs/hugetlbfs/inode.c~mm-bdi-add-separate-writeback-accounting-capability fs/hugetlbfs/inode.c --- a/fs/hugetlbfs/inode.c~mm-bdi-add-separate-writeback-accounting-capability +++ a/fs/hugetlbfs/inode.c @@ -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; diff -puN fs/ocfs2/dlm/dlmfs.c~mm-bdi-add-separate-writeback-accounting-capability fs/ocfs2/dlm/dlmfs.c --- a/fs/ocfs2/dlm/dlmfs.c~mm-bdi-add-separate-writeback-accounting-capability +++ a/fs/ocfs2/dlm/dlmfs.c @@ -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) diff -puN fs/ramfs/inode.c~mm-bdi-add-separate-writeback-accounting-capability fs/ramfs/inode.c --- a/fs/ramfs/inode.c~mm-bdi-add-separate-writeback-accounting-capability +++ a/fs/ramfs/inode.c @@ -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, }; diff -puN fs/sysfs/inode.c~mm-bdi-add-separate-writeback-accounting-capability fs/sysfs/inode.c --- a/fs/sysfs/inode.c~mm-bdi-add-separate-writeback-accounting-capability +++ a/fs/sysfs/inode.c @@ -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 ={ diff -puN include/linux/backing-dev.h~mm-bdi-add-separate-writeback-accounting-capability include/linux/backing-dev.h --- a/include/linux/backing-dev.h~mm-bdi-add-separate-writeback-accounting-capability +++ a/include/linux/backing-dev.h @@ -12,6 +12,7 @@ #include #include #include +#include #include struct page; @@ -151,22 +152,43 @@ 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 || \ @@ -206,17 +228,32 @@ 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 */ diff -puN kernel/cgroup.c~mm-bdi-add-separate-writeback-accounting-capability kernel/cgroup.c --- a/kernel/cgroup.c~mm-bdi-add-separate-writeback-accounting-capability +++ a/kernel/cgroup.c @@ -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) diff -puN mm/page-writeback.c~mm-bdi-add-separate-writeback-accounting-capability mm/page-writeback.c --- a/mm/page-writeback.c~mm-bdi-add-separate-writeback-accounting-capability +++ a/mm/page-writeback.c @@ -1246,7 +1246,7 @@ 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); } @@ -1275,7 +1275,7 @@ 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)) diff -puN mm/shmem.c~mm-bdi-add-separate-writeback-accounting-capability mm/shmem.c --- a/mm/shmem.c~mm-bdi-add-separate-writeback-accounting-capability +++ a/mm/shmem.c @@ -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, }; diff -puN mm/swap_state.c~mm-bdi-add-separate-writeback-accounting-capability mm/swap_state.c --- a/mm/swap_state.c~mm-bdi-add-separate-writeback-accounting-capability +++ a/mm/swap_state.c @@ -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, }; _