Hi Peter,
On 7/26/2024 5:48 PM, Peter Newman wrote:
Hi Babu,
On Wed, Jul 3, 2024 at 2:50 PM Babu Moger <babu.moger@xxxxxxx> wrote:
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 4f47f52e01c2..b3d3fa048f15 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -185,6 +185,23 @@ bool closid_allocated(unsigned int closid)
return !test_bit(closid, &closid_free_map);
}
+/*
+ * Counter bitmap and its length for tracking available counters.
+ * ABMC feature provides set of hardware counters for enabling events.
+ * Each event takes one hardware counter. Kernel needs to keep track
+ * of number of available counters.
+ */
+static unsigned long mbm_cntrs_free_map;
+static unsigned int mbm_cntrs_free_map_len;
If counter assignment is supported at a per-domain granularity, then
counter id allocation needs to be done per-domain rather than
globally. For example, if I free a counter from one group in a
particular domain, it should be available to allocate to another group
only in that domain.
Yes. I noticed the problem.
When I attempt this using the current series, the resulting behavior
is quite interesting. I noticed Reinette also commented on this later
in the series, noticing that counters are only allocated permanently
to groups and never move as a result of writing to mbm_control.
Working on fixing it right now.
We need to have bitmap at group level(global) as well as at domain
level. We need to set/clear bits at both the places when
assigned/unassigned. If all the domsins are cleared then we need to free
the counter at group level. Will address it v6. Thanks for the comments.
# grep 'g1[45]' info/L3_MON/mbm_control
test/g14/0=tl;1=tl;2=tl;3=tl;4=tl;5=tl;6=tl;7=tl;8=tl;9=tl;10=tl;11=tl;12=tl;13=tl;14=tl;15=tl;16=tl;17=tl;18=tl;19=tl;20=tl;21=tl;22=tl;23=tl;24=tl;25=tl;26=tl;27=tl;28=tl;29=tl;30=tl;31=tl;
test/g15/0=_;1=_;2=_;3=_;4=_;5=_;6=_;7=_;8=_;9=_;10=_;11=_;12=_;13=_;14=_;15=_;16=_;17=_;18=_;19=_;20=_;21=_;22=_;23=_;24=_;25=_;26=_;27=_;28=_;29=_;30=_;31=_;
[domains 2-31 omitted for clarity below]
# echo 'test/g14/1-t' > info/L3_MON/mbm_control
# grep 'g1[45]' info/L3_MON/mbm_control
test/g14/0=tl;1=l;
test/g15/0=_;1=_;
# echo "test/g15/1+t" > info/L3_MON/mbm_control
# grep 'g1[45]' info/L3_MON/mbm_control
test/g14/0=tl;1=_;
test/g15/0=_;1=_;
-Peter
--
- Babu Moger
