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Linux kernel stable tree
d8c47cc7bf
Once upon a time, all swapins counted toward memory pressure[1]. Then Joonsoo introduced workingset detection for anonymous pages and we gained the ability to distinguish hot from cold swapins[2][3]. But we failed to update swap_readpage() accordingly, and now we account partial memory pressure in the swapin path of cold memory. Not for all situations - which adds more inconsistency: paths using the conventional submit_bio() and lock_page() route will not see much pressure - unless storage itself is heavily congested and the bio submissions stall. ZRAM and ZSWAP do most of the work directly from swap_readpage() and will see all swapins reflected as pressure. IOW, a workload doing cold swapins could see little to no pressure reported with on-disk swap, but potentially high pressure with a zram or zswap backend. That confuses any psi-based health monitoring, load shedding, proactive reclaim, or userspace OOM killing schemes that might be in place for the workload. Restore consistency by making all swapin stall accounting conditional on the page actually being part of the workingset. [1] commit |
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| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| 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.