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." > + "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"? > + 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. Reinette
