Hello,
We've seen a significant perf degradation when reading a tmpfs file swapped into zram between 5.10 and 5.15. The source of the issue is:
* aa48e47e3906: memcg: infrastructure to flush memcg stats
There's a couple of commits that helps to bridge the gap in 5.16:
* 11192d9c124d: memcg: flush stats only if updated * fd25a9e0e23b: memcg: unify memcg stat flushing
Both of these apply cleanly and Shakeel (the author) has okayed the backport from his end. He also suggested backporting the following:
* 5b3be698a872: memcg: better bounds on the memcg stats updates
I personally did not test this one, but it applies cleanly, so there's probably no harm. I cc'd Shakeel in case you want confirmation on that. It's not a part of any tag yet.
Please backport all three (or at least the first two) to 5.15 LTS.
Thanks!
On Wed, Jan 19, 2022 at 04:15:34PM -0800, Ivan Babrou wrote:
Hello,
We've seen a significant perf degradation when reading a tmpfs file swapped into zram between 5.10 and 5.15. The source of the issue is:
- aa48e47e3906: memcg: infrastructure to flush memcg stats
There's a couple of commits that helps to bridge the gap in 5.16:
- 11192d9c124d: memcg: flush stats only if updated
- fd25a9e0e23b: memcg: unify memcg stat flushing
Both of these apply cleanly and Shakeel (the author) has okayed the backport from his end. He also suggested backporting the following:
- 5b3be698a872: memcg: better bounds on the memcg stats updates
I personally did not test this one, but it applies cleanly, so there's probably no harm. I cc'd Shakeel in case you want confirmation on that. It's not a part of any tag yet.
Please backport all three (or at least the first two) to 5.15 LTS.
All now queued up, thanks!
greg k-h
+Andrew & linux-mm
On Thu, Jan 27, 2022 at 7:30 AM Greg KH gregkh@linuxfoundation.org wrote:
On Wed, Jan 19, 2022 at 04:15:34PM -0800, Ivan Babrou wrote:
Hello,
We've seen a significant perf degradation when reading a tmpfs file swapped into zram between 5.10 and 5.15. The source of the issue is:
- aa48e47e3906: memcg: infrastructure to flush memcg stats
There's a couple of commits that helps to bridge the gap in 5.16:
- 11192d9c124d: memcg: flush stats only if updated
- fd25a9e0e23b: memcg: unify memcg stat flushing
Both of these apply cleanly and Shakeel (the author) has okayed the backport from his end. He also suggested backporting the following:
- 5b3be698a872: memcg: better bounds on the memcg stats updates
I personally did not test this one, but it applies cleanly, so there's probably no harm. I cc'd Shakeel in case you want confirmation on that. It's not a part of any tag yet.
Please backport all three (or at least the first two) to 5.15 LTS.
All now queued up, thanks!
Thanks Greg.
Adding Andrew (and linux-mm) in CC to let him know the reason for backporting these patches to 5.15 stable tree.
greg k-h
linux-stable-mirror@lists.linaro.org
-
Greg KH -
Ivan Babrou -
Shakeel Butt