Commit f7b1843e authored by James Morse's avatar James Morse Committed by Borislav Petkov
Browse files

x86/resctrl: Make resctrl_arch_rmid_read() return values in bytes 



resctrl_arch_rmid_read() returns a value in chunks, as read from the
hardware. This needs scaling to bytes by mon_scale, as provided by
the architecture code.

Now that resctrl_arch_rmid_read() performs the overflow and corrections
itself, it may as well return a value in bytes directly. This allows
the accesses to the architecture specific 'hw' structure to be removed.

Move the mon_scale conversion into resctrl_arch_rmid_read().
mbm_bw_count() is updated to calculate bandwidth from bytes.

Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarJamie Iles <quic_jiles@quicinc.com>
Reviewed-by: default avatarShaopeng Tan <tan.shaopeng@fujitsu.com>
Reviewed-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Tested-by: default avatarXin Hao <xhao@linux.alibaba.com>
Tested-by: default avatarShaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-by: default avatarCristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20220902154829.30399-22-james.morse@arm.com
parent d80975e2

arch/x86/kernel/cpu/resctrl/ctrlmondata.c

+2 −4
Original line number Diff line number Diff line
@@ -549,7 +549,6 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r, 
int rdtgroup_mondata_show(struct seq_file *m, void *arg)

{

	struct kernfs_open_file *of = m->private;

	struct rdt_hw_resource *hw_res;

	u32 resid, evtid, domid;

	struct rdtgroup *rdtgrp;

	struct rdt_resource *r;
@@ -569,8 +568,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg) 
	domid = md.u.domid;

	evtid = md.u.evtid;



	hw_res = &rdt_resources_all[resid];

	r = &hw_res->r_resctrl;

	r = &rdt_resources_all[resid].r_resctrl;

	d = rdt_find_domain(r, domid, NULL);

	if (IS_ERR_OR_NULL(d)) {

		ret = -ENOENT;
@@ -584,7 +582,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg) 
	else if (rr.err == -EINVAL)

		seq_puts(m, "Unavailable\n");

	else

		seq_printf(m, "%llu\n", rr.val * hw_res->mon_scale);

		seq_printf(m, "%llu\n", rr.val);



out:

	rdtgroup_kn_unlock(of->kn);

arch/x86/kernel/cpu/resctrl/internal.h

+2 −2
Original line number Diff line number Diff line
@@ -279,13 +279,13 @@ struct rftype { 


/**

 * struct mbm_state - status for each MBM counter in each domain

 * @prev_bw_chunks: Previous chunks value read for bandwidth calculation

 * @prev_bw_bytes: Previous bytes value read for bandwidth calculation

 * @prev_bw:	The most recent bandwidth in MBps

 * @delta_bw:	Difference between the current and previous bandwidth

 * @delta_comp:	Indicates whether to compute the delta_bw

 */

struct mbm_state {

	u64	prev_bw_chunks;

	u64	prev_bw_bytes;

	u32	prev_bw;

	u32	delta_bw;

	bool	delta_comp;

arch/x86/kernel/cpu/resctrl/monitor.c

+11 −13
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
 */



#include <linux/module.h>

#include <linux/sizes.h>

#include <linux/slab.h>



#include <asm/cpu_device_id.h>
@@ -189,7 +190,7 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d, 
	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);

	struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d);

	struct arch_mbm_state *am;

	u64 msr_val;

	u64 msr_val, chunks;



	if (!cpumask_test_cpu(smp_processor_id(), &d->cpu_mask))

		return -EINVAL;
@@ -214,12 +215,14 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d, 
	if (am) {

		am->chunks += mbm_overflow_count(am->prev_msr, msr_val,

						 hw_res->mbm_width);

		*val = get_corrected_mbm_count(rmid, am->chunks);

		chunks = get_corrected_mbm_count(rmid, am->chunks);

		am->prev_msr = msr_val;

	} else {

		*val = msr_val;

		chunks = msr_val;

	}



	*val = chunks * hw_res->mon_scale;



	return 0;

}
@@ -232,7 +235,6 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d, 
void __check_limbo(struct rdt_domain *d, bool force_free)

{

	struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;

	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);

	struct rmid_entry *entry;

	u32 crmid = 1, nrmid;

	bool rmid_dirty;
@@ -255,7 +257,6 @@ void __check_limbo(struct rdt_domain *d, bool force_free) 
					   QOS_L3_OCCUP_EVENT_ID, &val)) {

			rmid_dirty = true;

		} else {

			val *= hw_res->mon_scale;

			rmid_dirty = (val >= resctrl_rmid_realloc_threshold);

		}
@@ -299,7 +300,6 @@ int alloc_rmid(void) 
static void add_rmid_to_limbo(struct rmid_entry *entry)

{

	struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;

	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);

	struct rdt_domain *d;

	int cpu, err;

	u64 val = 0;
@@ -311,7 +311,6 @@ static void add_rmid_to_limbo(struct rmid_entry *entry) 
			err = resctrl_arch_rmid_read(r, d, entry->rmid,

						     QOS_L3_OCCUP_EVENT_ID,

						     &val);

			val *= hw_res->mon_scale;

			if (err || val <= resctrl_rmid_realloc_threshold)

				continue;

		}
@@ -403,15 +402,14 @@ static int __mon_event_count(u32 rmid, struct rmid_read *rr) 
 */

static void mbm_bw_count(u32 rmid, struct rmid_read *rr)

{

	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(rr->r);

	struct mbm_state *m = &rr->d->mbm_local[rmid];

	u64 cur_bw, chunks, cur_chunks;

	u64 cur_bw, bytes, cur_bytes;



	cur_chunks = rr->val;

	chunks = cur_chunks - m->prev_bw_chunks;

	m->prev_bw_chunks = cur_chunks;

	cur_bytes = rr->val;

	bytes = cur_bytes - m->prev_bw_bytes;

	m->prev_bw_bytes = cur_bytes;



	cur_bw = (chunks * hw_res->mon_scale) >> 20;

	cur_bw = bytes / SZ_1M;



	if (m->delta_comp)

		m->delta_bw = abs(cur_bw - m->prev_bw);

include/linux/resctrl.h

+1 −1
Original line number Diff line number Diff line
@@ -227,7 +227,7 @@ void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d); 
 * @d:			domain that the counter should be read from.

 * @rmid:		rmid of the counter to read.

 * @eventid:		eventid to read, e.g. L3 occupancy.

 * @val:		result of the counter read in chunks.

 * @val:		result of the counter read in bytes.

 *

 * Call from process context on a CPU that belongs to domain @d.

 *