cdc69458a5
The test_memcg_low() testcase in test_memcontrol.c verifies the expected
behavior of groups using the memory.low knob. Part of the testcase
verifies that a group with memory.low that experiences reclaim due to
memory pressure elsewhere in the system, observes memory.events.low events
as a result of that reclaim.
In commit 8a931f8013 ("mm: memcontrol: recursive memory.low
protection"), the memory controller was updated to propagate memory.low
and memory.min protection from a parent group to its children via a
configurable memory_recursiveprot mount option. This unfortunately broke
the memcg tests, which asserts that a sibling that experienced reclaim but
had a memory.low value of 0, would not observe any memory.low events.
This patch updates test_memcg_low() to account for the new behavior
introduced by memory_recursiveprot.
So as to make the test resilient to multiple configurations, the patch
also adds a new proc_mount_contains() helper that checks for a string in
/proc/mounts, and is used to toggle behavior based on whether the default
memory_recursiveprot was present.
Link: https://lkml.kernel.org/r/20220423155619.3669555-3-void@manifault.com
Signed-off-by: David Vernet <void@manifault.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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.