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Commit 19c635ab authored by Vikas Shivappa's avatar Vikas Shivappa Committed by Thomas Gleixner
Browse files

x86/intel_rdt/mba_sc: Enable/disable MBA software controller 



Currently user does memory bandwidth allocation(MBA) by specifying the
bandwidth in percentage via the resctrl schemata file:
	"/sys/fs/resctrl/schemata"

Add a new mount option "mba_MBps" to enable the user to specify MBA
in MBps:

$mount -t resctrl resctrl [-o cdp[,cdpl2][mba_MBps]] /sys/fs/resctrl

Signed-off-by: default avatarVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/1524263781-14267-3-git-send-email-vikas.shivappa@linux.intel.com
parent d6c64a4f

arch/x86/kernel/cpu/intel_rdt.c

+8 −0
Original line number Diff line number Diff line
@@ -230,6 +230,14 @@ static inline void cache_alloc_hsw_probe(void) 
	rdt_alloc_capable = true;

}



bool is_mba_sc(struct rdt_resource *r)

{

	if (!r)

		return rdt_resources_all[RDT_RESOURCE_MBA].membw.mba_sc;



	return r->membw.mba_sc;

}



/*

 * rdt_get_mb_table() - get a mapping of bandwidth(b/w) percentage values

 * exposed to user interface and the h/w understandable delay values.

arch/x86/kernel/cpu/intel_rdt.h

+3 −0
Original line number Diff line number Diff line
@@ -259,6 +259,7 @@ struct rdt_cache { 
 * @min_bw:		Minimum memory bandwidth percentage user can request

 * @bw_gran:		Granularity at which the memory bandwidth is allocated

 * @delay_linear:	True if memory B/W delay is in linear scale

 * @mba_sc:		True if MBA software controller(mba_sc) is enabled

 * @mb_map:		Mapping of memory B/W percentage to memory B/W delay

 */

struct rdt_membw {
@@ -266,6 +267,7 @@ struct rdt_membw { 
	u32		min_bw;

	u32		bw_gran;

	u32		delay_linear;

	bool		mba_sc;

	u32		*mb_map;

};
@@ -445,6 +447,7 @@ void mon_event_read(struct rmid_read *rr, struct rdt_domain *d, 
void mbm_setup_overflow_handler(struct rdt_domain *dom,

				unsigned long delay_ms);

void mbm_handle_overflow(struct work_struct *work);

bool is_mba_sc(struct rdt_resource *r);

void cqm_setup_limbo_handler(struct rdt_domain *dom, unsigned long delay_ms);

void cqm_handle_limbo(struct work_struct *work);

bool has_busy_rmid(struct rdt_resource *r, struct rdt_domain *d);

arch/x86/kernel/cpu/intel_rdt_rdtgroup.c

+30 −0
Original line number Diff line number Diff line
@@ -1005,6 +1005,11 @@ static void l2_qos_cfg_update(void *arg) 
	wrmsrl(IA32_L2_QOS_CFG, *enable ? L2_QOS_CDP_ENABLE : 0ULL);

}



static inline bool is_mba_linear(void)

{

	return rdt_resources_all[RDT_RESOURCE_MBA].membw.delay_linear;

}



static int set_cache_qos_cfg(int level, bool enable)

{

	void (*update)(void *arg);
@@ -1041,6 +1046,25 @@ static int set_cache_qos_cfg(int level, bool enable) 
	return 0;

}



/*

 * Enable or disable the MBA software controller

 * which helps user specify bandwidth in MBps.

 * MBA software controller is supported only if

 * MBM is supported and MBA is in linear scale.

 */

static int set_mba_sc(bool mba_sc)

{

	struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_MBA];



	if (!is_mbm_enabled() || !is_mba_linear() ||

	    mba_sc == is_mba_sc(r))

		return -EINVAL;



	r->membw.mba_sc = mba_sc;



	return 0;

}



static int cdp_enable(int level, int data_type, int code_type)

{

	struct rdt_resource *r_ldata = &rdt_resources_all[data_type];
@@ -1123,6 +1147,10 @@ static int parse_rdtgroupfs_options(char *data) 
			ret = cdpl2_enable();

			if (ret)

				goto out;

		} else if (!strcmp(token, "mba_MBps")) {

			ret = set_mba_sc(true);

			if (ret)

				goto out;

		} else {

			ret = -EINVAL;

			goto out;
@@ -1445,6 +1473,8 @@ static void rdt_kill_sb(struct super_block *sb) 
	cpus_read_lock();

	mutex_lock(&rdtgroup_mutex);



	set_mba_sc(false);



	/*Put everything back to default values. */

	for_each_alloc_enabled_rdt_resource(r)

		reset_all_ctrls(r);