| Message ID | 20230110152003.1118777-1-chao@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | proc: introduce proc_statfs() | expand |
On Tue, Jan 10, 2023 at 11:20:03PM +0800, Chao Yu wrote: > Introduce proc_statfs() to replace simple_statfs(), so that > f_bsize queried from statfs() can be consistent w/ the value we > set in s_blocksize. > > stat -f /proc/ > > Before: > ID: 0 Namelen: 255 Type: proc > Block size: 4096 Fundamental block size: 4096 > Blocks: Total: 0 Free: 0 Available: 0 > Inodes: Total: 0 Free: 0 > > After: > ID: 0 Namelen: 255 Type: proc > Block size: 1024 Fundamental block size: 1024 > Blocks: Total: 0 Free: 0 Available: 0 > Inodes: Total: 0 Free: 0 4096 is better value is in fact. seq_files allocate 1 page and fill it, therefore reading less than PAGE_SIZE from /proc is mostly waste of syscalls. I doubt anything uses f_bsize. BTW this patch is not self contained.
On 2023/1/11 1:58, Alexey Dobriyan wrote: > On Tue, Jan 10, 2023 at 11:20:03PM +0800, Chao Yu wrote: >> Introduce proc_statfs() to replace simple_statfs(), so that >> f_bsize queried from statfs() can be consistent w/ the value we >> set in s_blocksize. >> >> stat -f /proc/ >> >> Before: >> ID: 0 Namelen: 255 Type: proc >> Block size: 4096 Fundamental block size: 4096 >> Blocks: Total: 0 Free: 0 Available: 0 >> Inodes: Total: 0 Free: 0 >> >> After: >> ID: 0 Namelen: 255 Type: proc >> Block size: 1024 Fundamental block size: 1024 >> Blocks: Total: 0 Free: 0 Available: 0 >> Inodes: Total: 0 Free: 0 > > 4096 is better value is in fact. > > seq_files allocate 1 page and fill it, therefore reading less than > PAGE_SIZE from /proc is mostly waste of syscalls. Ah, thanks for correcting me, so, how about updating .s_blocksize and .s_blocksize_bits to PAGE_SIZE and PAGE_SHIFT? > > I doubt anything uses f_bsize. > > BTW this patch is not self contained. Oh, yes, my bad. Thanks,
diff --git a/fs/proc/inode.c b/fs/proc/inode.c index f495fdb39151..d39e3b9b3135 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -25,6 +25,7 @@ #include <linux/slab.h> #include <linux/mount.h> #include <linux/bug.h> +#include <linux/statfs.h> #include "internal.h" @@ -176,6 +177,14 @@ static inline const char *hidepid2str(enum proc_hidepid v) return "unknown"; } +static int proc_statfs(struct dentry *dentry, struct kstatfs *buf) +{ + buf->f_type = dentry->d_sb->s_magic; + buf->f_bsize = dentry->d_sb->s_blocksize; + buf->f_namelen = PROC_NAME_LEN; + return 0; +} + static int proc_show_options(struct seq_file *seq, struct dentry *root) { struct proc_fs_info *fs_info = proc_sb_info(root->d_sb); @@ -195,7 +204,7 @@ const struct super_operations proc_sops = { .free_inode = proc_free_inode, .drop_inode = generic_delete_inode, .evict_inode = proc_evict_inode, - .statfs = simple_statfs, + .statfs = proc_statfs, .show_options = proc_show_options, };
Introduce proc_statfs() to replace simple_statfs(), so that f_bsize queried from statfs() can be consistent w/ the value we set in s_blocksize. stat -f /proc/ Before: ID: 0 Namelen: 255 Type: proc Block size: 4096 Fundamental block size: 4096 Blocks: Total: 0 Free: 0 Available: 0 Inodes: Total: 0 Free: 0 After: ID: 0 Namelen: 255 Type: proc Block size: 1024 Fundamental block size: 1024 Blocks: Total: 0 Free: 0 Available: 0 Inodes: Total: 0 Free: 0 Signed-off-by: Chao Yu <chao@kernel.org> --- fs/proc/inode.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)