Commit ac7de456 authored by Babu Moger's avatar Babu Moger Committed by Borislav Petkov (AMD)
Browse files

fs/resctrl: Update bit_usage to reflect io_alloc 



The "shareable_bits" and "bit_usage" resctrl files associated with cache
resources give insight into how instances of a cache is used.

Update the annotated capacity bitmasks displayed by "bit_usage" to include the
cache portions allocated for I/O via the "io_alloc" feature. "shareable_bits"
is a global bitmask of shareable cache with I/O and can thus not present the
per-domain I/O allocations possible with the "io_alloc" feature. Revise the
"shareable_bits" documentation to direct users to "bit_usage" for accurate
cache usage information.

Signed-off-by: default avatarBabu Moger <babu.moger@amd.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Link: https://patch.msgid.link/e02a0d424129fd7f3e45822a559b1c614ae4652a.1762995456.git.babu.moger@amd.com
parent 28fa2cce

Documentation/filesystems/resctrl.rst

+21 −14
Original line number Diff line number Diff line
@@ -96,12 +96,19 @@ related to allocation: 
		must be set when writing a mask.



"shareable_bits":

		Bitmask of shareable resource with other executing

		entities (e.g. I/O). User can use this when

		setting up exclusive cache partitions. Note that

		some platforms support devices that have their

		own settings for cache use which can over-ride

		these bits.

		Bitmask of shareable resource with other executing entities

		(e.g. I/O). Applies to all instances of this resource. User

		can use this when setting up exclusive cache partitions.

		Note that some platforms support devices that have their

		own settings for cache use which can over-ride these bits.



		When "io_alloc" is enabled, a portion of each cache instance can

		be configured for shared use between hardware and software.

		"bit_usage" should be used to see which portions of each cache

		instance is configured for hardware use via "io_alloc" feature

		because every cache instance can have its "io_alloc" bitmask

		configured independently via "io_alloc_cbm".



"bit_usage":

		Annotated capacity bitmasks showing how all

		instances of the resource are used. The legend is:
@@ -115,16 +122,16 @@ related to allocation: 
			"H":

			      Corresponding region is used by hardware only

			      but available for software use. If a resource

			      has bits set in "shareable_bits" but not all

			      of these bits appear in the resource groups'

			      schematas then the bits appearing in

			      "shareable_bits" but no resource group will

			      be marked as "H".

			      has bits set in "shareable_bits" or "io_alloc_cbm"

			      but not all of these bits appear in the resource

			      groups' schemata then the bits appearing in

			      "shareable_bits" or "io_alloc_cbm" but no

			      resource group will be marked as "H".

			"X":

			      Corresponding region is available for sharing and

			      used by hardware and software. These are the

			      bits that appear in "shareable_bits" as

			      well as a resource group's allocation.

			      used by hardware and software. These are the bits

			      that appear in "shareable_bits" or "io_alloc_cbm"

			      as well as a resource group's allocation.

			"S":

			      Corresponding region is used by software

			      and available for sharing.

fs/resctrl/ctrlmondata.c

+1 −1
Original line number Diff line number Diff line
@@ -750,7 +750,7 @@ static int resctrl_io_alloc_init_cbm(struct resctrl_schema *s, u32 closid) 
 * resource. Note that if Code Data Prioritization (CDP) is enabled, the number

 * of available CLOSIDs is reduced by half.

 */

static u32 resctrl_io_alloc_closid(struct rdt_resource *r)

u32 resctrl_io_alloc_closid(struct rdt_resource *r)

{

	if (resctrl_arch_get_cdp_enabled(r->rid))

		return resctrl_arch_get_num_closid(r) / 2  - 1;

fs/resctrl/internal.h

+1 −0
Original line number Diff line number Diff line
@@ -442,6 +442,7 @@ int resctrl_io_alloc_cbm_show(struct kernfs_open_file *of, struct seq_file *seq, 
			      void *v);

ssize_t resctrl_io_alloc_cbm_write(struct kernfs_open_file *of, char *buf,

				   size_t nbytes, loff_t off);

u32 resctrl_io_alloc_closid(struct rdt_resource *r);



#ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK

int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp);

fs/resctrl/rdtgroup.c

+19 −2
Original line number Diff line number Diff line
@@ -1062,15 +1062,17 @@ static int rdt_bit_usage_show(struct kernfs_open_file *of, 


	cpus_read_lock();

	mutex_lock(&rdtgroup_mutex);

	hw_shareable = r->cache.shareable_bits;

	list_for_each_entry(dom, &r->ctrl_domains, hdr.list) {

		if (sep)

			seq_putc(seq, ';');

		hw_shareable = r->cache.shareable_bits;

		sw_shareable = 0;

		exclusive = 0;

		seq_printf(seq, "%d=", dom->hdr.id);

		for (i = 0; i < closids_supported(); i++) {

			if (!closid_allocated(i))

			if (!closid_allocated(i) ||

			    (resctrl_arch_get_io_alloc_enabled(r) &&

			     i == resctrl_io_alloc_closid(r)))

				continue;

			ctrl_val = resctrl_arch_get_config(r, dom, i,

							   s->conf_type);
@@ -1098,6 +1100,21 @@ static int rdt_bit_usage_show(struct kernfs_open_file *of, 
				break;

			}

		}



		/*

		 * When the "io_alloc" feature is enabled, a portion of the cache

		 * is configured for shared use between hardware and software.

		 * Also, when CDP is enabled the CBMs of CDP_CODE and CDP_DATA

		 * resources are kept in sync. So, the CBMs for "io_alloc" can

		 * be accessed through either resource.

		 */

		if (resctrl_arch_get_io_alloc_enabled(r)) {

			ctrl_val = resctrl_arch_get_config(r, dom,

							   resctrl_io_alloc_closid(r),

							   s->conf_type);

			hw_shareable |= ctrl_val;

		}



		for (i = r->cache.cbm_len - 1; i >= 0; i--) {

			pseudo_locked = dom->plr ? dom->plr->cbm : 0;

			hwb = test_bit(i, &hw_shareable);