[SRU][jammy][PATCH 0/1] performance: address_space: add padding for i_map and i_mmap_rwsem to mitigate a false sharing

[Philip Cox]

BugLink: https://bugs.launchpad.net/bugs/2053069

SRU Justification:

[Impact]
In high core count systems such as Intel Sapphire Rapids
(with a 112C/224T count) this this change improvesgeekbench performance by
~5.3% due to moving the elements in the address_space struct.

[Fix]
by moving i_mmap_rwsema, vma_interval_tree_remove is no longer in cacheline 0
which improves the performance.


[Test Plan]
I've tested this change, as has Intel.  This change has also been upstreamed
for some time.

[Where problems could occur]
The risk for regression is fairly low, as we are just changing the layout
of a stuct to change where members land in the cache.

--

Zhu, Lipeng (1):
  fs/address_space: add alignment padding for i_map and i_mmap_rwsem to
    mitigate a false sharing.

 include/linux/fs.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.34.1