Hi Reinette,
On 8/7/2025 8:48 PM, Reinette Chatre wrote:
Hi Babu,
On 8/5/25 4:30 PM, Babu Moger wrote:
"io_alloc" feature in resctrl allows direct insertion of data from I/O
devices into the cache.
Introduce the 'io_alloc' resctrl file to indicate the support for the
feature.
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
...
---
Documentation/filesystems/resctrl.rst | 29 +++++++++++++++++++++++++++
fs/resctrl/ctrlmondata.c | 21 +++++++++++++++++++
fs/resctrl/internal.h | 5 +++++
fs/resctrl/rdtgroup.c | 24 +++++++++++++++++++++-
4 files changed, 78 insertions(+), 1 deletion(-)
diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index f08699030312..fff7e04d1e2a 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -136,6 +136,35 @@ 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":
+ Portions of cache used for allocation of I/O traffic
+ cannot be configured.
To help distinguish difference between "disabled" and "not supported" it may be useful
to prepend something like "Resource supports "io_alloc" but the feature is disabled."
Sure. Added it now.
+ "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.
+
+ The underlying implementation may reduce resources available to
+ general (CPU) cache allocation. See architecture specific notes
+ below. Depending on usage requirements the feature can be enabled
+ or disabled.
+
+ On AMD systems, the io_alloc feature is supported by the L3 Smart
drop "the"?
Sure.
+ Data Cache Injection Allocation Enforcement (SDCIAE). The CLOSID for
+ io_alloc is the highest CLOSID supported by the resource. When
+ io_alloc is enabled, the highest CLOSID is dedicated to io_alloc and
+ no longer available for general (CPU) cache allocation. When CDP is
+ enabled, io_alloc routes I/O traffic using the highest CLOSID allocated
+ for the instruction cache (L3CODE), making this CLOSID no longer
+ available for general (CPU) cache allocation for both the L3CODE and
+ L3DATA resources.
+
Memory bandwidth(MB) subdirectory contains the following files
with respect to allocation:
Code looks good to me.
Thanks
Babu
