From nobody Thu Oct 2 15:35:04 2025 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1A7D22FD1CB; Mon, 15 Sep 2025 11:27:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757935649; cv=none; b=rmj7/S6XCkgwmQDs6jW8Bp8ypAFqakB2y8A1PM2JLZW5kBFJJPvr5aoF7TDhjFJqOd4zp2FvaCEIbjAuqrCZLBawWBTPb4pCSPfXKR2dZgcX7WI2OCj/VN/sSzuXbmfmFqy8HE3tZk7LfrriHpt6htESzN2IvUxCfl5+/2QRzoc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757935649; c=relaxed/simple; bh=jp6lkdwm1kU1rgIGPCGzlppOd+hV90OpOdESZBvfTaM=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=Y/XfWq/4VM2GO21L2qgKDeRHPkwuPr84KZ4mJ6mt+OPW91ir9u4gfObYLq4lv9wAvXkv2dc5UTe8RW0XrS9cNQmNKWDxoq+aLEGqCoZMlz4I2H3nJWd0I6seiR/4GynGeQG5F768JCGgiuZA+Uidk2YrTA1q34grPxCewa3g+F0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=buyN0hlC; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=nGfsXoov; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="buyN0hlC"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="nGfsXoov" Date: Mon, 15 Sep 2025 11:27:24 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1757935645; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8kDbbnrQYKWVUiwa2ZXRZx3hTzbU31Yt75YobPgcwWc=; b=buyN0hlCqzyfSK8lq2pya2W8CpERHJL46QhblkDzUjtR2OObC+YQq5XLRJOQ7RM4sHExT9 Pla32TIi+5ndFLM2wWzYbgVHQZh8nqMHGMpgYX0Gr0jRvQ6hgjenboHeStEnzupNLXXbmf 1SfRdavGyf8Fc5BSYdeLDr/R0IAHlqY2j1IWyYlEIxofuBUeSHRmJdPUbwQyCccaPYAcom /JgJh38bTm5UhI5ggOdbMX1N6QINSLunVKD84qWMVEhdb2Yo1joRkWY4KmdUyrc38jVSpW H+/HBOl7l/rhFFBa7u1v2ojt69IEfhf2iYOoStAfGqaGIMsAfZIUG+K6dcWNKA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1757935645; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8kDbbnrQYKWVUiwa2ZXRZx3hTzbU31Yt75YobPgcwWc=; b=nGfsXoovU03HHTckr32WDag0T7xbSsAX0A/LT8wfsWOu9l4xVsrOmyoms1Qjb/sqd/n0Nh u78/hBwloZLxvgBg== From: "tip-bot2 for Babu Moger" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/cache] fs/resctrl: Introduce the interface to modify assignments in a group Cc: Babu Moger , "Borislav Petkov (AMD)" , Reinette Chatre , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <175793564412.709179.8478610566418953842.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the x86/cache branch of tip: Commit-ID: 88bee79640aea6192f98c8faae30e0013453479d Gitweb: https://git.kernel.org/tip/88bee79640aea6192f98c8faae30e0013= 453479d Author: Babu Moger AuthorDate: Fri, 05 Sep 2025 16:34:28 -05:00 Committer: Borislav Petkov (AMD) CommitterDate: Mon, 15 Sep 2025 12:47:17 +02:00 fs/resctrl: Introduce the interface to modify assignments in a group Enable the mbm_l3_assignments resctrl file to be used to modify counter assignments of CTRL_MON and MON groups when the "mbm_event" counter assignment mode is enabled. Process the assignment modifications in the following format: :=3D;=3D Event: A valid MBM event in the /sys/fs/resctrl/info/L3_MON/event_configs directory. Domain ID: A valid domain ID. When writing, '*' applies the changes to all domains. Assignment states: _ : Unassign a counter. e : Assign a counter exclusively. Examples: $ cd /sys/fs/resctrl $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=3De;1=3De mbm_local_bytes:0=3De;1=3De To unassign the counter associated with the mbm_total_bytes event on domain 0: $ echo "mbm_total_bytes:0=3D_" > mbm_L3_assignments $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=3D_;1=3De mbm_local_bytes:0=3De;1=3De To unassign the counter associated with the mbm_total_bytes event on all the domains: $ echo "mbm_total_bytes:*=3D_" > mbm_L3_assignments $ cat /sys/fs/resctrl/mbm_L3_assignments mbm_total_bytes:0=3D_;1=3D_ mbm_local_bytes:0=3De;1=3De Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com --- Documentation/filesystems/resctrl.rst | 151 ++++++++++++++++++++++++- fs/resctrl/internal.h | 3 +- fs/resctrl/monitor.c | 139 +++++++++++++++++++++++- fs/resctrl/rdtgroup.c | 3 +- 4 files changed, 294 insertions(+), 2 deletions(-) diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesyst= ems/resctrl.rst index a2b7240..f60f6a9 100644 --- a/Documentation/filesystems/resctrl.rst +++ b/Documentation/filesystems/resctrl.rst @@ -522,7 +522,8 @@ When monitoring is enabled all MON groups may also cont= ain: Event: A valid MBM event in the /sys/fs/resctrl/info/L3_MON/event_configs directory. =20 - Domain ID: A valid domain ID. + Domain ID: A valid domain ID. When writing, '*' applies the changes + to all the domains. =20 Assignment states: =20 @@ -540,6 +541,35 @@ When monitoring is enabled all MON groups may also con= tain: mbm_total_bytes:0=3De;1=3De mbm_local_bytes:0=3De;1=3De =20 + Assignments can be modified by writing to the interface. + + Examples: + + To unassign the counter associated with the mbm_total_bytes event on doma= in 0: + :: + + # echo "mbm_total_bytes:0=3D_" > /sys/fs/resctrl/mbm_L3_assignments + # cat /sys/fs/resctrl/mbm_L3_assignments + mbm_total_bytes:0=3D_;1=3De + mbm_local_bytes:0=3De;1=3De + + To unassign the counter associated with the mbm_total_bytes event on all = the domains: + :: + + # echo "mbm_total_bytes:*=3D_" > /sys/fs/resctrl/mbm_L3_assignments + # cat /sys/fs/resctrl/mbm_L3_assignments + mbm_total_bytes:0=3D_;1=3D_ + mbm_local_bytes:0=3De;1=3De + + To assign a counter associated with the mbm_total_bytes event on all doma= ins in + exclusive mode: + :: + + # echo "mbm_total_bytes:*=3De" > /sys/fs/resctrl/mbm_L3_assignments + # cat /sys/fs/resctrl/mbm_L3_assignments + mbm_total_bytes:0=3De;1=3De + mbm_local_bytes:0=3De;1=3De + When the "mba_MBps" mount option is used all CTRL_MON groups will also con= tain: =20 "mba_MBps_event": @@ -1585,6 +1615,125 @@ View the llc occupancy snapshot:: # cat /sys/fs/resctrl/p1/mon_data/mon_L3_00/llc_occupancy 11234000 =20 + +Examples on working with mbm_assign_mode +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +a. Check if MBM counter assignment mode is supported. +:: + + # mount -t resctrl resctrl /sys/fs/resctrl/ + + # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode + [mbm_event] + default + +The "mbm_event" mode is detected and enabled. + +b. Check how many assignable counters are supported. +:: + + # cat /sys/fs/resctrl/info/L3_MON/num_mbm_cntrs + 0=3D32;1=3D32 + +c. Check how many assignable counters are available for assignment in each= domain. +:: + + # cat /sys/fs/resctrl/info/L3_MON/available_mbm_cntrs + 0=3D30;1=3D30 + +d. To list the default group's assign states. +:: + + # cat /sys/fs/resctrl/mbm_L3_assignments + mbm_total_bytes:0=3De;1=3De + mbm_local_bytes:0=3De;1=3De + +e. To unassign the counter associated with the mbm_total_bytes event on d= omain 0. +:: + + # echo "mbm_total_bytes:0=3D_" > /sys/fs/resctrl/mbm_L3_assignments + # cat /sys/fs/resctrl/mbm_L3_assignments + mbm_total_bytes:0=3D_;1=3De + mbm_local_bytes:0=3De;1=3De + +f. To unassign the counter associated with the mbm_total_bytes event on al= l domains. +:: + + # echo "mbm_total_bytes:*=3D_" > /sys/fs/resctrl/mbm_L3_assignments + # cat /sys/fs/resctrl/mbm_L3_assignment + mbm_total_bytes:0=3D_;1=3D_ + mbm_local_bytes:0=3De;1=3De + +g. To assign a counter associated with the mbm_total_bytes event on all do= mains in +exclusive mode. +:: + + # echo "mbm_total_bytes:*=3De" > /sys/fs/resctrl/mbm_L3_assignments + # cat /sys/fs/resctrl/mbm_L3_assignments + mbm_total_bytes:0=3De;1=3De + mbm_local_bytes:0=3De;1=3De + +h. Read the events mbm_total_bytes and mbm_local_bytes of the default grou= p. There is +no change in reading the events with the assignment. +:: + + # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_total_bytes + 779247936 + # cat /sys/fs/resctrl/mon_data/mon_L3_01/mbm_total_bytes + 562324232 + # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_bytes + 212122123 + # cat /sys/fs/resctrl/mon_data/mon_L3_01/mbm_local_bytes + 121212144 + +i. Check the event configurations. +:: + + # cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_total_bytes/event_fi= lter + local_reads,remote_reads,local_non_temporal_writes,remote_non_temporal_w= rites, + local_reads_slow_memory,remote_reads_slow_memory,dirty_victim_writes_all + + # cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_local_bytes/event_fi= lter + local_reads,local_non_temporal_writes,local_reads_slow_memory + +j. Change the event configuration for mbm_local_bytes. +:: + + # echo "local_reads, local_non_temporal_writes, local_reads_slow_memory,= remote_reads" > + /sys/fs/resctrl/info/L3_MON/event_configs/mbm_local_bytes/event_filter + + # cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_local_bytes/event_fi= lter + local_reads,local_non_temporal_writes,local_reads_slow_memory,remote_rea= ds + +k. Now read the local events again. The first read may come back with "Una= vailable" +status. The subsequent read of mbm_local_bytes will display the current va= lue. +:: + + # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_bytes + Unavailable + # cat /sys/fs/resctrl/mon_data/mon_L3_00/mbm_local_bytes + 2252323 + # cat /sys/fs/resctrl/mon_data/mon_L3_01/mbm_local_bytes + Unavailable + # cat /sys/fs/resctrl/mon_data/mon_L3_01/mbm_local_bytes + 1566565 + +l. Users have the option to go back to 'default' mbm_assign_mode if requir= ed. This can be +done using the following command. Note that switching the mbm_assign_mode = may reset all +the MBM counters (and thus all MBM events) of all the resctrl groups. +:: + + # echo "default" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode + # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode + mbm_event + [default] + +m. Unmount the resctrl filesystem. +:: + + # umount /sys/fs/resctrl/ + Intel RDT Errata =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h index 43297b3..c69b1da 100644 --- a/fs/resctrl/internal.h +++ b/fs/resctrl/internal.h @@ -418,6 +418,9 @@ ssize_t resctrl_mbm_assign_on_mkdir_write(struct kernfs= _open_file *of, char *buf =20 int mbm_L3_assignments_show(struct kernfs_open_file *of, struct seq_file *= s, void *v); =20 +ssize_t mbm_L3_assignments_write(struct kernfs_open_file *of, char *buf, s= ize_t nbytes, + loff_t off); + #ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp); =20 diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c index b692a0e..f388dbc 100644 --- a/fs/resctrl/monitor.c +++ b/fs/resctrl/monitor.c @@ -1502,6 +1502,145 @@ out_unlock: return ret; } =20 +/* + * mbm_get_mon_event_by_name() - Return the mon_evt entry for the matching + * event name. + */ +static struct mon_evt *mbm_get_mon_event_by_name(struct rdt_resource *r, c= har *name) +{ + struct mon_evt *mevt; + + for_each_mon_event(mevt) { + if (mevt->rid =3D=3D r->rid && mevt->enabled && + resctrl_is_mbm_event(mevt->evtid) && + !strcmp(mevt->name, name)) + return mevt; + } + + return NULL; +} + +static int rdtgroup_modify_assign_state(char *assign, struct rdt_mon_domai= n *d, + struct rdtgroup *rdtgrp, struct mon_evt *mevt) +{ + int ret =3D 0; + + if (!assign || strlen(assign) !=3D 1) + return -EINVAL; + + switch (*assign) { + case 'e': + ret =3D rdtgroup_assign_cntr_event(d, rdtgrp, mevt); + break; + case '_': + rdtgroup_unassign_cntr_event(d, rdtgrp, mevt); + break; + default: + ret =3D -EINVAL; + break; + } + + return ret; +} + +static int resctrl_parse_mbm_assignment(struct rdt_resource *r, struct rdt= group *rdtgrp, + char *event, char *tok) +{ + struct rdt_mon_domain *d; + unsigned long dom_id =3D 0; + char *dom_str, *id_str; + struct mon_evt *mevt; + int ret; + + mevt =3D mbm_get_mon_event_by_name(r, event); + if (!mevt) { + rdt_last_cmd_printf("Invalid event %s\n", event); + return -ENOENT; + } + +next: + if (!tok || tok[0] =3D=3D '\0') + return 0; + + /* Start processing the strings for each domain */ + dom_str =3D strim(strsep(&tok, ";")); + + id_str =3D strsep(&dom_str, "=3D"); + + /* Check for domain id '*' which means all domains */ + if (id_str && *id_str =3D=3D '*') { + ret =3D rdtgroup_modify_assign_state(dom_str, NULL, rdtgrp, mevt); + if (ret) + rdt_last_cmd_printf("Assign operation '%s:*=3D%s' failed\n", + event, dom_str); + return ret; + } else if (!id_str || kstrtoul(id_str, 10, &dom_id)) { + rdt_last_cmd_puts("Missing domain id\n"); + return -EINVAL; + } + + /* Verify if the dom_id is valid */ + list_for_each_entry(d, &r->mon_domains, hdr.list) { + if (d->hdr.id =3D=3D dom_id) { + ret =3D rdtgroup_modify_assign_state(dom_str, d, rdtgrp, mevt); + if (ret) { + rdt_last_cmd_printf("Assign operation '%s:%ld=3D%s' failed\n", + event, dom_id, dom_str); + return ret; + } + goto next; + } + } + + rdt_last_cmd_printf("Invalid domain id %ld\n", dom_id); + return -EINVAL; +} + +ssize_t mbm_L3_assignments_write(struct kernfs_open_file *of, char *buf, + size_t nbytes, loff_t off) +{ + struct rdt_resource *r =3D resctrl_arch_get_resource(RDT_RESOURCE_L3); + struct rdtgroup *rdtgrp; + char *token, *event; + int ret =3D 0; + + /* Valid input requires a trailing newline */ + if (nbytes =3D=3D 0 || buf[nbytes - 1] !=3D '\n') + return -EINVAL; + + buf[nbytes - 1] =3D '\0'; + + rdtgrp =3D rdtgroup_kn_lock_live(of->kn); + if (!rdtgrp) { + rdtgroup_kn_unlock(of->kn); + return -ENOENT; + } + rdt_last_cmd_clear(); + + if (!resctrl_arch_mbm_cntr_assign_enabled(r)) { + rdt_last_cmd_puts("mbm_event mode is not enabled\n"); + rdtgroup_kn_unlock(of->kn); + return -EINVAL; + } + + while ((token =3D strsep(&buf, "\n")) !=3D NULL) { + /* + * The write command follows the following format: + * ":=3D" + * Extract the event name first. + */ + event =3D strsep(&token, ":"); + + ret =3D resctrl_parse_mbm_assignment(r, rdtgrp, event, token); + if (ret) + break; + } + + rdtgroup_kn_unlock(of->kn); + + return ret ?: nbytes; +} + /** * resctrl_mon_resource_init() - Initialise global monitoring structures. * diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c index 519aa6a..bd4a115 100644 --- a/fs/resctrl/rdtgroup.c +++ b/fs/resctrl/rdtgroup.c @@ -1939,9 +1939,10 @@ static struct rftype res_common_files[] =3D { }, { .name =3D "mbm_L3_assignments", - .mode =3D 0444, + .mode =3D 0644, .kf_ops =3D &rdtgroup_kf_single_ops, .seq_show =3D mbm_L3_assignments_show, + .write =3D mbm_L3_assignments_write, }, { .name =3D "mbm_assign_mode",