Commit 28fa2cce authored by Babu Moger's avatar Babu Moger Committed by Borislav Petkov (AMD)
Browse files

fs/resctrl: Introduce interface to modify io_alloc capacity bitmasks 



The io_alloc feature in resctrl enables system software to configure the
portion of the cache allocated for I/O traffic. When supported, the
io_alloc_cbm file in resctrl provides access to capacity bitmasks (CBMs)
allocated for I/O devices.

Enable users to modify io_alloc CBMs by writing to the io_alloc_cbm resctrl
file when the io_alloc feature is enabled.

Mirror the CBMs between CDP_CODE and CDP_DATA when CDP is enabled to present
consistent I/O allocation information to user space.

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/67609641b03ccfba18a8ee0bf9dbd1f3dcbecda3.1762995456.git.babu.moger@amd.com
parent af1242ee

Documentation/filesystems/resctrl.rst

+12 −0
Original line number Diff line number Diff line
@@ -196,6 +196,18 @@ related to allocation: 
			# cat /sys/fs/resctrl/info/L3/io_alloc_cbm

			0=ffff;1=ffff



		CBMs can be configured by writing to the interface.



		Example::



			# echo 1=ff > /sys/fs/resctrl/info/L3/io_alloc_cbm

			# cat /sys/fs/resctrl/info/L3/io_alloc_cbm

			0=ffff;1=00ff



			# echo "0=ff;1=f" > /sys/fs/resctrl/info/L3/io_alloc_cbm

			# cat /sys/fs/resctrl/info/L3/io_alloc_cbm

			0=00ff;1=000f



		When CDP is enabled "io_alloc_cbm" associated with the CDP_DATA and CDP_CODE

		resources may reflect the same values. For example, values read from and

		written to /sys/fs/resctrl/info/L3DATA/io_alloc_cbm may be reflected by

fs/resctrl/ctrlmondata.c

+93 −0
Original line number Diff line number Diff line
@@ -864,3 +864,96 @@ int resctrl_io_alloc_cbm_show(struct kernfs_open_file *of, struct seq_file *seq, 
	cpus_read_unlock();

	return ret;

}



static int resctrl_io_alloc_parse_line(char *line,  struct rdt_resource *r,

				       struct resctrl_schema *s, u32 closid)

{

	enum resctrl_conf_type peer_type;

	struct rdt_parse_data data;

	struct rdt_ctrl_domain *d;

	char *dom = NULL, *id;

	unsigned long dom_id;



next:

	if (!line || line[0] == '\0')

		return 0;



	dom = strsep(&line, ";");

	id = strsep(&dom, "=");

	if (!dom || kstrtoul(id, 10, &dom_id)) {

		rdt_last_cmd_puts("Missing '=' or non-numeric domain\n");

		return -EINVAL;

	}



	dom = strim(dom);

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

		if (d->hdr.id == dom_id) {

			data.buf = dom;

			data.mode = RDT_MODE_SHAREABLE;

			data.closid = closid;

			if (parse_cbm(&data, s, d))

				return -EINVAL;

			/*

			 * Keep io_alloc CLOSID's CBM of CDP_CODE and CDP_DATA

			 * in sync.

			 */

			if (resctrl_arch_get_cdp_enabled(r->rid)) {

				peer_type = resctrl_peer_type(s->conf_type);

				memcpy(&d->staged_config[peer_type],

				       &d->staged_config[s->conf_type],

				       sizeof(d->staged_config[0]));

			}

			goto next;

		}

	}



	return -EINVAL;

}



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

				   size_t nbytes, loff_t off)

{

	struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);

	struct rdt_resource *r = s->res;

	u32 io_alloc_closid;

	int ret = 0;



	/* Valid input requires a trailing newline */

	if (nbytes == 0 || buf[nbytes - 1] != '\n')

		return -EINVAL;



	buf[nbytes - 1] = '\0';



	cpus_read_lock();

	mutex_lock(&rdtgroup_mutex);

	rdt_last_cmd_clear();



	if (!r->cache.io_alloc_capable) {

		rdt_last_cmd_printf("io_alloc is not supported on %s\n", s->name);

		ret = -ENODEV;

		goto out_unlock;

	}



	if (!resctrl_arch_get_io_alloc_enabled(r)) {

		rdt_last_cmd_printf("io_alloc is not enabled on %s\n", s->name);

		ret = -EINVAL;

		goto out_unlock;

	}



	io_alloc_closid = resctrl_io_alloc_closid(r);



	rdt_staged_configs_clear();

	ret = resctrl_io_alloc_parse_line(buf, r, s, io_alloc_closid);

	if (ret)

		goto out_clear_configs;



	ret = resctrl_arch_update_domains(r, io_alloc_closid);



out_clear_configs:

	rdt_staged_configs_clear();

out_unlock:

	mutex_unlock(&rdtgroup_mutex);

	cpus_read_unlock();



	return ret ?: nbytes;

}

fs/resctrl/internal.h

+2 −0
Original line number Diff line number Diff line
@@ -440,6 +440,8 @@ ssize_t resctrl_io_alloc_write(struct kernfs_open_file *of, char *buf, 
const char *rdtgroup_name_by_closid(u32 closid);

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);



#ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK

int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp);

fs/resctrl/rdtgroup.c

+2 −1
Original line number Diff line number Diff line
@@ -1973,9 +1973,10 @@ static struct rftype res_common_files[] = { 
	},

	{

		.name		= "io_alloc_cbm",

		.mode		= 0444,

		.mode		= 0644,

		.kf_ops		= &rdtgroup_kf_single_ops,

		.seq_show	= resctrl_io_alloc_cbm_show,

		.write		= resctrl_io_alloc_cbm_write,

	},

	{

		.name		= "max_threshold_occupancy",