From d2bf45d067c728b0fe6e8f99a7386b8291e391e3 Mon Sep 17 00:00:00 2001 From: Aaron Tomlin Date: Tue, 24 Mar 2026 20:11:59 -0400 Subject: fs/resctrl: Add "*" shorthand to set io_alloc CBM for all domains Configuring the io_alloc_cbm interface requires an explicit domain ID for each cache domain. On systems with high core counts and numerous cache clusters, this requirement becomes cumbersome for automation and management tasks that aim to apply a uniform policy. Introduce a wildcard domain ID selector "*" for the io_alloc_cbm interface. This enables users to set the same Capacity Bitmask (CBM) across all cache domains in a single operation. Signed-off-by: Aaron Tomlin Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Reviewed-by: Babu Moger Tested-by: Babu Moger Link: https://patch.msgid.link/20260325001159.447075-3-atomlin@atomlin.com --- Documentation/filesystems/resctrl.rst | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'Documentation') diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst index ba609f8d4de5..b003bed339fd 100644 --- a/Documentation/filesystems/resctrl.rst +++ b/Documentation/filesystems/resctrl.rst @@ -215,6 +215,14 @@ related to allocation: # cat /sys/fs/resctrl/info/L3/io_alloc_cbm 0=00ff;1=000f + An ID of "*" configures all domains with the provided CBM. + + Example on a system that does not require a minimum number of consecutive bits in the mask:: + + # echo "*=0" > /sys/fs/resctrl/info/L3/io_alloc_cbm + # cat /sys/fs/resctrl/info/L3/io_alloc_cbm + 0=0;1=0 + When CDP is enabled "io_alloc_cbm" associated with the CDP_DATA and CDP_CODE resources may reflect the same values. For example, values read from and written to /sys/fs/resctrl/info/L3DATA/io_alloc_cbm may be reflected by -- cgit v1.2.3