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authorBabu Moger <babu.moger@amd.com>2025-11-12 18:57:36 -0600
committerBorislav Petkov (AMD) <bp@alien8.de>2025-11-22 14:30:34 +0100
commitac7de456a37f9b126eb53b89c2bb27d625dc5fd9 (patch)
treeaf9b8996c0010ad185554a8843656f94ca103f59 /Documentation/filesystems
parent28fa2cce7a8388f09e457f1e24241ca6d5e985d8 (diff)
downloadtip-ac7de456a37f9b126eb53b89c2bb27d625dc5fd9.tar.gz
fs/resctrl: Update bit_usage to reflect io_allocx86_cache_for_v6.19_rc1x86/cache
The "shareable_bits" and "bit_usage" resctrl files associated with cache resources give insight into how instances of a cache is used. Update the annotated capacity bitmasks displayed by "bit_usage" to include the cache portions allocated for I/O via the "io_alloc" feature. "shareable_bits" is a global bitmask of shareable cache with I/O and can thus not present the per-domain I/O allocations possible with the "io_alloc" feature. Revise the "shareable_bits" documentation to direct users to "bit_usage" for accurate cache usage information. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/e02a0d424129fd7f3e45822a559b1c614ae4652a.1762995456.git.babu.moger@amd.com
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/resctrl.rst35
1 files changed, 21 insertions, 14 deletions
diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index bbc4b6cbb71dce..8c8ce678148a52 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -96,12 +96,19 @@ related to allocation:
must be set when writing a mask.
"shareable_bits":
- Bitmask of shareable resource with other executing
- entities (e.g. I/O). User can use this when
- setting up exclusive cache partitions. Note that
- some platforms support devices that have their
- own settings for cache use which can over-ride
- these bits.
+ Bitmask of shareable resource with other executing entities
+ (e.g. I/O). Applies to all instances of this resource. User
+ can use this when setting up exclusive cache partitions.
+ Note that some platforms support devices that have their
+ own settings for cache use which can over-ride these bits.
+
+ When "io_alloc" is enabled, a portion of each cache instance can
+ be configured for shared use between hardware and software.
+ "bit_usage" should be used to see which portions of each cache
+ instance is configured for hardware use via "io_alloc" feature
+ because every cache instance can have its "io_alloc" bitmask
+ configured independently via "io_alloc_cbm".
+
"bit_usage":
Annotated capacity bitmasks showing how all
instances of the resource are used. The legend is:
@@ -115,16 +122,16 @@ related to allocation:
"H":
Corresponding region is used by hardware only
but available for software use. If a resource
- has bits set in "shareable_bits" but not all
- of these bits appear in the resource groups'
- schematas then the bits appearing in
- "shareable_bits" but no resource group will
- be marked as "H".
+ has bits set in "shareable_bits" or "io_alloc_cbm"
+ but not all of these bits appear in the resource
+ groups' schemata then the bits appearing in
+ "shareable_bits" or "io_alloc_cbm" but no
+ resource group will be marked as "H".
"X":
Corresponding region is available for sharing and
- used by hardware and software. These are the
- bits that appear in "shareable_bits" as
- well as a resource group's allocation.
+ used by hardware and software. These are the bits
+ that appear in "shareable_bits" or "io_alloc_cbm"
+ as well as a resource group's allocation.
"S":
Corresponding region is used by software
and available for sharing.