From 48068e565045ee0c77fdb34225ac6dedb5871fc2 Mon Sep 17 00:00:00 2001 From: Babu Moger Date: Wed, 12 Nov 2025 18:57:31 -0600 Subject: fs/resctrl: Introduce interface to display "io_alloc" support Introduce the "io_alloc" resctrl file to the "info" area of a cache resource, for example /sys/fs/resctrl/info/L3/io_alloc. "io_alloc" indicates support for the "io_alloc" feature that allows direct insertion of data from I/O devices into the cache. Restrict exposing support for "io_alloc" to the L3 resource that is the only resource where this feature can be backed by AMD's L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE). With that, the "io_alloc" file is only visible to user space if the L3 resource supports "io_alloc". Doing so makes the file visible for all cache resources though, for example also L2 cache (if it supports cache allocation). As a consequence, add capability for file to report expected "enabled" and "disabled", as well as "not supported". Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://patch.msgid.link/e8b116a8f424128b227734bb1d433c14af478d90.1762995456.git.babu.moger@amd.com --- Documentation/filesystems/resctrl.rst | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'Documentation') diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst index d7a51cae6b26..108995640ca5 100644 --- a/Documentation/filesystems/resctrl.rst +++ b/Documentation/filesystems/resctrl.rst @@ -137,6 +137,21 @@ related to allocation: "1": Non-contiguous 1s value in CBM is supported. +"io_alloc": + "io_alloc" enables system software to configure the portion of + the cache allocated for I/O traffic. File may only exist if the + system supports this feature on some of its cache resources. + + "disabled": + Resource supports "io_alloc" but the feature is disabled. + Portions of cache used for allocation of I/O traffic cannot + be configured. + "enabled": + Portions of cache used for allocation of I/O traffic + can be configured using "io_alloc_cbm". + "not supported": + Support not available for this resource. + Memory bandwidth(MB) subdirectory contains the following files with respect to allocation: -- cgit v1.2.3