| Message ID | 20240622154904.3774273-3-yu.ma@intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | fs/file.c: optimize the critical section of file_lock in | expand |
On Sat 22-06-24 11:49:03, Yu Ma wrote: > 64 bits in open_fds are mapped to a common bit in full_fds_bits. It is very > likely that a bit in full_fds_bits has been cleared before in > __clear_open_fds()'s operation. Check the clear bit in full_fds_bits before > clearing to avoid unnecessary write and cache bouncing. See commit fc90888d07b8 > ("vfs: conditionally clear close-on-exec flag") for a similar optimization. > Together with patch 1, they improves pts/blogbench-1.1.0 read for 27%, and write > for 14% on Intel ICX 160 cores configuration with v6.10-rc4. > > Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> > Signed-off-by: Yu Ma <yu.ma@intel.com> Nice. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > fs/file.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/fs/file.c b/fs/file.c > index 50e900a47107..b4d25f6d4c19 100644 > --- a/fs/file.c > +++ b/fs/file.c > @@ -268,7 +268,9 @@ static inline void __set_open_fd(unsigned int fd, struct fdtable *fdt) > static inline void __clear_open_fd(unsigned int fd, struct fdtable *fdt) > { > __clear_bit(fd, fdt->open_fds); > - __clear_bit(fd / BITS_PER_LONG, fdt->full_fds_bits); > + fd /= BITS_PER_LONG; > + if (test_bit(fd, fdt->full_fds_bits)) > + __clear_bit(fd, fdt->full_fds_bits); > } > > static inline bool fd_is_open(unsigned int fd, const struct fdtable *fdt) > -- > 2.43.0 >
On 6/25/2024 7:54 PM, Jan Kara wrote: > On Sat 22-06-24 11:49:03, Yu Ma wrote: >> 64 bits in open_fds are mapped to a common bit in full_fds_bits. It is very >> likely that a bit in full_fds_bits has been cleared before in >> __clear_open_fds()'s operation. Check the clear bit in full_fds_bits before >> clearing to avoid unnecessary write and cache bouncing. See commit fc90888d07b8 >> ("vfs: conditionally clear close-on-exec flag") for a similar optimization. >> Together with patch 1, they improves pts/blogbench-1.1.0 read for 27%, and write >> for 14% on Intel ICX 160 cores configuration with v6.10-rc4. >> >> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> >> Signed-off-by: Yu Ma <yu.ma@intel.com> > Nice. Feel free to add: > > Reviewed-by: Jan Kara <jack@suse.cz> > > Honza Copy that, thanks Honza :) >> --- >> fs/file.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/fs/file.c b/fs/file.c >> index 50e900a47107..b4d25f6d4c19 100644 >> --- a/fs/file.c >> +++ b/fs/file.c >> @@ -268,7 +268,9 @@ static inline void __set_open_fd(unsigned int fd, struct fdtable *fdt) >> static inline void __clear_open_fd(unsigned int fd, struct fdtable *fdt) >> { >> __clear_bit(fd, fdt->open_fds); >> - __clear_bit(fd / BITS_PER_LONG, fdt->full_fds_bits); >> + fd /= BITS_PER_LONG; >> + if (test_bit(fd, fdt->full_fds_bits)) >> + __clear_bit(fd, fdt->full_fds_bits); >> } >> >> static inline bool fd_is_open(unsigned int fd, const struct fdtable *fdt) >> -- >> 2.43.0 >>
diff --git a/fs/file.c b/fs/file.c index 50e900a47107..b4d25f6d4c19 100644 --- a/fs/file.c +++ b/fs/file.c @@ -268,7 +268,9 @@ static inline void __set_open_fd(unsigned int fd, struct fdtable *fdt) static inline void __clear_open_fd(unsigned int fd, struct fdtable *fdt) { __clear_bit(fd, fdt->open_fds); - __clear_bit(fd / BITS_PER_LONG, fdt->full_fds_bits); + fd /= BITS_PER_LONG; + if (test_bit(fd, fdt->full_fds_bits)) + __clear_bit(fd, fdt->full_fds_bits); } static inline bool fd_is_open(unsigned int fd, const struct fdtable *fdt)
64 bits in open_fds are mapped to a common bit in full_fds_bits. It is very likely that a bit in full_fds_bits has been cleared before in __clear_open_fds()'s operation. Check the clear bit in full_fds_bits before clearing to avoid unnecessary write and cache bouncing. See commit fc90888d07b8 ("vfs: conditionally clear close-on-exec flag") for a similar optimization. Together with patch 1, they improves pts/blogbench-1.1.0 read for 27%, and write for 14% on Intel ICX 160 cores configuration with v6.10-rc4. Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Yu Ma <yu.ma@intel.com> --- fs/file.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)