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9fe8fec5e4
hfi1_mmu_rb_remove_unless_exact() did not move mmu_rb_node objects in
mmu_rb_handler->lru_list after getting a cache hit on an mmu_rb_node.
As a result, hfi1_mmu_rb_evict() was not guaranteed to evict truly
least-recently used nodes.
This could be a performance issue for an application when that
application:
- Uses some long-lived buffers frequently.
- Uses a large number of buffers once.
- Hits the mmu_rb_handler cache size or pinned-page limits, forcing
mmu_rb_handler cache entries to be evicted.
In this case, the one-time use buffers cause the long-lived buffer
entries to eventually filter to the end of the LRU list where
hfi1_mmu_rb_evict() will consider evicting a frequently-used long-lived
entry instead of evicting one of the one-time use entries.
Fix this by inserting new mmu_rb_node at the tail of
mmu_rb_handler->lru_list and move mmu_rb_ndoe to the tail of
mmu_rb_handler->lru_list when the mmu_rb_node is a hit in
hfi1_mmu_rb_remove_unless_exact(). Change hfi1_mmu_rb_evict() to evict
from the head of mmu_rb_handler->lru_list instead of the tail.
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.