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| author | Reinette Chatre <reinette.chatre@intel.com> | 2020-05-05 15:36:16 -0700 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-05-06 18:00:35 +0200 |
| commit | 46637d4570e108d1f6721cfa2cca1d078882761a (patch) | |
| tree | a1f111536d4d336a62704668a0922a37b3d1c6e2 /arch/x86/kernel/cpu/resctrl/internal.h | |
| parent | 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 (diff) | |
| download | linux-46637d4570e108d1f6721cfa2cca1d078882761a.tar.bz2 | |
x86/resctrl: Maintain MBM counter width per resource
The original Memory Bandwidth Monitoring (MBM) architectural
definition defines counters of up to 62 bits in the IA32_QM_CTR MSR,
and the first-generation MBM implementation uses 24 bit counters.
Software is required to poll at 1 second or faster to ensure that
data is retrieved before a counter rollover occurs more than once
under worst conditions.
As system bandwidths scale the software requirement is maintained with
the introduction of a per-resource enumerable MBM counter width.
In preparation for supporting hardware with an enumerable MBM counter
width the current globally static MBM counter width is moved to a
per-resource MBM counter width. Currently initialized to 24 always
to result in no functional change.
In essence there is one function, mbm_overflow_count() that needs to
know the counter width to handle rollovers. The static value
used within mbm_overflow_count() will be replaced with a value
discovered from the hardware. Support for learning the MBM counter
width from hardware is added in the change that follows.
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/e36743b9800f16ce600f86b89127391f61261f23.1588715690.git.reinette.chatre@intel.com
Diffstat (limited to 'arch/x86/kernel/cpu/resctrl/internal.h')
| -rw-r--r-- | arch/x86/kernel/cpu/resctrl/internal.h | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index 3dd13f3a8b23..58b002c31655 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -87,6 +87,7 @@ union mon_data_bits { struct rmid_read { struct rdtgroup *rgrp; + struct rdt_resource *r; struct rdt_domain *d; int evtid; bool first; @@ -460,6 +461,7 @@ struct rdt_resource { struct list_head evt_list; int num_rmid; unsigned int mon_scale; + unsigned int mbm_width; unsigned long fflags; }; @@ -587,8 +589,9 @@ void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r, unsigned int dom_id); void mkdir_mondata_subdir_allrdtgrp(struct rdt_resource *r, struct rdt_domain *d); -void mon_event_read(struct rmid_read *rr, struct rdt_domain *d, - struct rdtgroup *rdtgrp, int evtid, int first); +void mon_event_read(struct rmid_read *rr, struct rdt_resource *r, + struct rdt_domain *d, struct rdtgroup *rdtgrp, + int evtid, int first); void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms); void mbm_handle_overflow(struct work_struct *work); |