Commit d80975e2 authored by James Morse's avatar James Morse Committed by Borislav Petkov
Browse files

x86/resctrl: Add resctrl_rmid_realloc_limit to abstract x86's boot_cpu_data 



resctrl_rmid_realloc_threshold can be set by user-space. The maximum
value is specified by the architecture.

Currently max_threshold_occ_write() reads the maximum value from
boot_cpu_data.x86_cache_size, which is not portable to another
architecture.

Add resctrl_rmid_realloc_limit to describe the maximum size in bytes
that user-space can set the threshold to.

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/20220902154829.30399-21-james.morse@arm.com
parent ae2328b5

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

+7 −2
Original line number Diff line number Diff line
@@ -67,6 +67,11 @@ unsigned int rdt_mon_features; 
 */

unsigned int resctrl_rmid_realloc_threshold;



/*

 * This is the maximum value for the reallocation threshold, in bytes.

 */

unsigned int resctrl_rmid_realloc_limit;



#define CF(cf)	((unsigned long)(1048576 * (cf) + 0.5))



/*
@@ -747,10 +752,10 @@ int rdt_get_mon_l3_config(struct rdt_resource *r) 
{

	unsigned int mbm_offset = boot_cpu_data.x86_cache_mbm_width_offset;

	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);

	unsigned int cl_size = boot_cpu_data.x86_cache_size;

	unsigned int threshold;

	int ret;



	resctrl_rmid_realloc_limit = boot_cpu_data.x86_cache_size * 1024;

	hw_res->mon_scale = boot_cpu_data.x86_cache_occ_scale;

	r->num_rmid = boot_cpu_data.x86_cache_max_rmid + 1;

	hw_res->mbm_width = MBM_CNTR_WIDTH_BASE;
@@ -767,7 +772,7 @@ int rdt_get_mon_l3_config(struct rdt_resource *r) 
	 *

	 * For a 35MB LLC and 56 RMIDs, this is ~1.8% of the LLC.

	 */

	threshold = cl_size * 1024 / r->num_rmid;

	threshold = resctrl_rmid_realloc_limit / r->num_rmid;



	/*

	 * Because num_rmid may not be a power of two, round the value

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

+1 −1
Original line number Diff line number Diff line
@@ -1059,7 +1059,7 @@ static ssize_t max_threshold_occ_write(struct kernfs_open_file *of, 
	if (ret)

		return ret;



	if (bytes > (boot_cpu_data.x86_cache_size * 1024))

	if (bytes > resctrl_rmid_realloc_limit)

		return -EINVAL;



	resctrl_rmid_realloc_threshold = resctrl_arch_round_mon_val(bytes);

include/linux/resctrl.h

+1 −0
Original line number Diff line number Diff line
@@ -251,5 +251,6 @@ void resctrl_arch_reset_rmid(struct rdt_resource *r, struct rdt_domain *d, 
			     u32 rmid, enum resctrl_event_id eventid);



extern unsigned int resctrl_rmid_realloc_threshold;

extern unsigned int resctrl_rmid_realloc_limit;



#endif /* _RESCTRL_H */