| Message ID | 20230421014750.2315938-1-goldstein.w.n@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v1] ext4: move `ext4_count_free` to ext4.h so it can be easily inlined | expand |
On Thu 20-04-23 20:47:49, Noah Goldstein wrote: > `ext4_count_free` is a one-line helper that is clearly better off > being inlined. This saves a handful instructions in `vmlinux` on x86. > > Instruction estimates use `wc -l` on `objdump` > Before: 8539271 > After : 8539248 > > So saves roughly 20 instructions > > Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com> Looks fine. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > fs/ext4/bitmap.c | 5 ----- > fs/ext4/ext4.h | 6 +++++- > 2 files changed, 5 insertions(+), 6 deletions(-) > > diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c > index f63e028c638c..c3cd2b878bbd 100644 > --- a/fs/ext4/bitmap.c > +++ b/fs/ext4/bitmap.c > @@ -11,11 +11,6 @@ > #include <linux/buffer_head.h> > #include "ext4.h" > > -unsigned int ext4_count_free(char *bitmap, unsigned int numchars) > -{ > - return numchars * BITS_PER_BYTE - memweight(bitmap, numchars); > -} > - > int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group, > struct ext4_group_desc *gdp, > struct buffer_head *bh, int sz) > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > index 08b29c289da4..6e1d3c175a70 100644 > --- a/fs/ext4/ext4.h > +++ b/fs/ext4/ext4.h > @@ -2675,7 +2675,11 @@ struct mmpd_data { > # define NORET_AND noreturn, > > /* bitmap.c */ > -extern unsigned int ext4_count_free(char *bitmap, unsigned numchars); > +static inline unsigned int ext4_count_free(char *bitmap, unsigned int numchars) > +{ > + return numchars * BITS_PER_BYTE - memweight(bitmap, numchars); > +} > + > void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group, > struct ext4_group_desc *gdp, > struct buffer_head *bh, int sz); > -- > 2.34.1 >
On Mon, Apr 24, 2023 at 11:24 AM Jan Kara <jack@suse.cz> wrote: > > On Thu 20-04-23 20:47:49, Noah Goldstein wrote: > > `ext4_count_free` is a one-line helper that is clearly better off > > being inlined. This saves a handful instructions in `vmlinux` on x86. > > > > Instruction estimates use `wc -l` on `objdump` > > Before: 8539271 > > After : 8539248 > > > > So saves roughly 20 instructions > > > > Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com> > > Looks fine. Feel free to add: > > Reviewed-by: Jan Kara <jack@suse.cz> > Done, thank you. > Honza > > > --- > > fs/ext4/bitmap.c | 5 ----- > > fs/ext4/ext4.h | 6 +++++- > > 2 files changed, 5 insertions(+), 6 deletions(-) > > > > diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c > > index f63e028c638c..c3cd2b878bbd 100644 > > --- a/fs/ext4/bitmap.c > > +++ b/fs/ext4/bitmap.c > > @@ -11,11 +11,6 @@ > > #include <linux/buffer_head.h> > > #include "ext4.h" > > > > -unsigned int ext4_count_free(char *bitmap, unsigned int numchars) > > -{ > > - return numchars * BITS_PER_BYTE - memweight(bitmap, numchars); > > -} > > - > > int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group, > > struct ext4_group_desc *gdp, > > struct buffer_head *bh, int sz) > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > > index 08b29c289da4..6e1d3c175a70 100644 > > --- a/fs/ext4/ext4.h > > +++ b/fs/ext4/ext4.h > > @@ -2675,7 +2675,11 @@ struct mmpd_data { > > # define NORET_AND noreturn, > > > > /* bitmap.c */ > > -extern unsigned int ext4_count_free(char *bitmap, unsigned numchars); > > +static inline unsigned int ext4_count_free(char *bitmap, unsigned int numchars) > > +{ > > + return numchars * BITS_PER_BYTE - memweight(bitmap, numchars); > > +} > > + > > void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group, > > struct ext4_group_desc *gdp, > > struct buffer_head *bh, int sz); > > -- > > 2.34.1 > > > -- > Jan Kara <jack@suse.com> > SUSE Labs, CR
diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c index f63e028c638c..c3cd2b878bbd 100644 --- a/fs/ext4/bitmap.c +++ b/fs/ext4/bitmap.c @@ -11,11 +11,6 @@ #include <linux/buffer_head.h> #include "ext4.h" -unsigned int ext4_count_free(char *bitmap, unsigned int numchars) -{ - return numchars * BITS_PER_BYTE - memweight(bitmap, numchars); -} - int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group, struct ext4_group_desc *gdp, struct buffer_head *bh, int sz) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 08b29c289da4..6e1d3c175a70 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2675,7 +2675,11 @@ struct mmpd_data { # define NORET_AND noreturn, /* bitmap.c */ -extern unsigned int ext4_count_free(char *bitmap, unsigned numchars); +static inline unsigned int ext4_count_free(char *bitmap, unsigned int numchars) +{ + return numchars * BITS_PER_BYTE - memweight(bitmap, numchars); +} + void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group, struct ext4_group_desc *gdp, struct buffer_head *bh, int sz);
`ext4_count_free` is a one-line helper that is clearly better off being inlined. This saves a handful instructions in `vmlinux` on x86. Instruction estimates use `wc -l` on `objdump` Before: 8539271 After : 8539248 So saves roughly 20 instructions Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com> --- fs/ext4/bitmap.c | 5 ----- fs/ext4/ext4.h | 6 +++++- 2 files changed, 5 insertions(+), 6 deletions(-)