mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-25 05:34:00 +08:00
buffer: Avoid setting buffer bits that are already set
It's expensive to set buffer flags that are already set, because that causes a costly cache line transition. A common case is setting the "verified" flag during ext4 writes. This patch checks for the flag being set first. With the AIM7/creat-clo benchmark testing on a 48G ramdisk based-on ext4 file system, we see 3.3%(15431->15936) improvement of aim7.jobs-per-min on a 2-sockets broadwell platform. What the benchmark does is: it forks 3000 processes, and each process do the following: a) open a new file b) close the file c) delete the file until loop=100*1000 times. The original patch is contributed by Andi Kleen. Signed-off-by: Andi Kleen <ak@linux.intel.com> Tested-by: Kemi Wang <kemi.wang@intel.com> Signed-off-by: Kemi Wang <kemi.wang@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
parent
bea99a5007
commit
60f91826ca
@ -81,11 +81,14 @@ struct buffer_head {
|
||||
/*
|
||||
* macro tricks to expand the set_buffer_foo(), clear_buffer_foo()
|
||||
* and buffer_foo() functions.
|
||||
* To avoid reset buffer flags that are already set, because that causes
|
||||
* a costly cache line transition, check the flag first.
|
||||
*/
|
||||
#define BUFFER_FNS(bit, name) \
|
||||
static __always_inline void set_buffer_##name(struct buffer_head *bh) \
|
||||
{ \
|
||||
set_bit(BH_##bit, &(bh)->b_state); \
|
||||
if (!test_bit(BH_##bit, &(bh)->b_state)) \
|
||||
set_bit(BH_##bit, &(bh)->b_state); \
|
||||
} \
|
||||
static __always_inline void clear_buffer_##name(struct buffer_head *bh) \
|
||||
{ \
|
||||
|
Loading…
Reference in New Issue
Block a user