[Bug 2053069] Re: performance: address_space: add padding for i_map and i_mmap_rwsem to mitigate a false sharing

This bug is awaiting verification that the linux-xilinx-
zynqmp/5.15.0-1029.33 kernel in -proposed solves the problem. Please
test the kernel and update this bug with the results. If the problem is
solved, change the tag 'verification-needed-jammy-linux-xilinx-zynqmp'
to 'verification-done-jammy-linux-xilinx-zynqmp'. If the problem still
exists, change the tag 'verification-needed-jammy-linux-xilinx-zynqmp'
to 'verification-failed-jammy-linux-xilinx-zynqmp'.


If verification is not done by 5 working days from today, this fix will
be dropped from the source code, and this bug will be closed.


See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how
to enable and use -proposed. Thank you!


** Tags added: kernel-spammed-jammy-linux-xilinx-zynqmp-v2 verification-needed-jammy-linux-xilinx-zynqmp

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

Title:
performance: address_space: add padding for i_map and i_mmap_rwsem to
mitigate a false sharing

Status in linux package in Ubuntu:
Invalid
Status in linux source package in Jammy:
Fix Released

Bug description:
This is a public version of https://bugs.launchpad.net/bugs/2034983

[Description]
When running UnixBench/shell1&shell8&exelc cases, we observed high false sharing for accessing i_mmap against i_mmap_rwsem.
The patch places the i_mmap and i_mmap_rwsem in separate cache lines to avoid this false sharing problem.

[Hardware Information]
Architecture:
Intel / AMD (x86_64)
Platform(s):
DNP
Date HW is expected at Canonical:

Component(s):
Performance and Scalability

[Software Information]
Target Version:
23.10
Target Kernel:
TBD
Commit IDs:
aee79d4e5271 fs/address_space: add alignment padding for i_map and i_mmap_rwsem to mitigate a false sharing.
External Links:

[Business Justification]

[Testing guidance]

[External ID]
OSVE-5159


Here's the commit ID: aee79d4e5271cee4ffa89ed830189929a6272eb8

https://github.com/torvalds/linux/commit/aee79d4e5271cee4ffa89ed830189929a6272eb8

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