xref: /linux/Documentation/ABI/testing/sysfs-kernel-mm-mempolicy-weighted-interleave (revision 00c010e130e58301db2ea0cec1eadc931e1cb8cf)
1What:		/sys/kernel/mm/mempolicy/weighted_interleave/
2Date:		January 2024
3Contact:	Linux memory management mailing list <linux-mm@kvack.org>
4Description:	Configuration Interface for the Weighted Interleave policy
5
6What:		/sys/kernel/mm/mempolicy/weighted_interleave/nodeN
7Date:		January 2024
8Contact:	Linux memory management mailing list <linux-mm@kvack.org>
9Description:	Weight configuration interface for nodeN
10
11		The interleave weight for a memory node (N). These weights are
12		utilized by tasks which have set their mempolicy to
13		MPOL_WEIGHTED_INTERLEAVE.
14
15		These weights only affect new allocations, and changes at runtime
16		will not cause migrations on already allocated pages.
17
18		The minimum weight for a node is always 1.
19
20		Minimum weight: 1
21		Maximum weight: 255
22
23		Writing invalid values (i.e. any values not in [1,255],
24		empty string, ...) will return -EINVAL.
25
26		Changing the weight to a valid value will automatically
27		switch the system to manual mode as well.
28
29What:		/sys/kernel/mm/mempolicy/weighted_interleave/auto
30Date:		May 2025
31Contact:	Linux memory management mailing list <linux-mm@kvack.org>
32Description:	Auto-weighting configuration interface
33
34		Configuration mode for weighted interleave. 'true' indicates
35		that the system is in auto mode, and a 'false' indicates that
36		the system is in manual mode.
37
38		In auto mode, all node weights are re-calculated and overwritten
39		(visible via the nodeN interfaces) whenever new bandwidth data
40		is made available during either boot or hotplug events.
41
42		In manual mode, node weights can only be updated by the user.
43		Note that nodes that are onlined with previously set weights
44		will reuse those weights. If they were not previously set or
45		are onlined with missing bandwidth data, the weights will use
46		a default weight of 1.
47
48		Writing any true value string (e.g. Y or 1) will enable auto
49		mode, while writing any false value string (e.g. N or 0) will
50		enable manual mode. All other strings are ignored and will
51		return -EINVAL.
52
53		Writing a new weight to a node directly via the nodeN interface
54		will also automatically switch the system to manual mode.
55