diff options
| author | Jan Glauber <jglauber@cavium.com> | 2019-06-05 16:48:49 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-06-07 23:15:06 +0300 |
| commit | 893a7d32e8e04ca4d6c882336b26ed660ca0a48d (patch) | |
| tree | dc6946c02bd1d17178e8ac9b4925513834490e11 /include | |
| parent | d93445225cd3c8eb0bf1350c04875576428b45b4 (diff) | |
| download | linux-893a7d32e8e04ca4d6c882336b26ed660ca0a48d.tar.xz | |
lockref: Limit number of cmpxchg loop retries
The lockref cmpxchg loop is unbound as long as the spinlock is not
taken. Depending on the hardware implementation of compare-and-swap
a high number of loop retries might happen.
Add an upper bound to the loop to force the fallback to spinlocks
after some time. A retry value of 100 should not impact any hardware
that does not have this issue.
With the retry limit the performance of an open-close testcase
improved between 60-70% on ThunderX2.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jan Glauber <jglauber@marvell.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
0 files changed, 0 insertions, 0 deletions