linux-kernel - [tip: x86/cache] x86/resctrl: Handle removing directories in Sub-NUMA Cluster (SNC) mode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <171994825282.2215.4608981062416265571.tip-bot2@tip-bot2>
Date: Tue, 02 Jul 2024 19:24:12 -0000
From: "tip-bot2 for Tony Luck" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Tony Luck <tony.luck@...el.com>, "Borislav Petkov (AMD)" <bp@...en8.de>,
 Reinette Chatre <reinette.chatre@...el.com>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: x86/cache] x86/resctrl: Handle removing directories in Sub-NUMA
 Cluster (SNC) mode

The following commit has been merged into the x86/cache branch of tip:

Commit-ID:     6b48b80b08e6f08eea8eaf7e44555ada191b6bee
Gitweb:        https://git.kernel.org/tip/6b48b80b08e6f08eea8eaf7e44555ada191b6bee
Author:        Tony Luck <tony.luck@...el.com>
AuthorDate:    Tue, 02 Jul 2024 10:38:19 -07:00
Committer:     Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Tue, 02 Jul 2024 19:51:06 +02:00

x86/resctrl: Handle removing directories in Sub-NUMA Cluster (SNC) mode

In SNC mode, there are multiple subdirectories in each L3 level monitor
directory (one for each SNC node). If all the CPUs in an SNC node are taken
offline, just remove the SNC directory for that node. In non-SNC mode, or when
the last SNC node directory is removed, remove the L3 monitor directory.

Add a helper function to avoid duplicated code.

Signed-off-by: Tony Luck <tony.luck@...el.com>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>
Link: https://lore.kernel.org/r/20240702173820.90368-2-tony.luck@intel.com
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 35 ++++++++++++++++++++-----
 1 file changed, 29 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 8502385..58e53f1 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -3006,22 +3006,45 @@ static int mon_addfile(struct kernfs_node *parent_kn, const char *name,
 	return ret;
 }
 
+static void mon_rmdir_one_subdir(struct kernfs_node *pkn, char *name, char *subname)
+{
+	struct kernfs_node *kn;
+
+	kn = kernfs_find_and_get(pkn, name);
+	if (!kn)
+		return;
+	kernfs_put(kn);
+
+	if (kn->dir.subdirs <= 1)
+		kernfs_remove(kn);
+	else
+		kernfs_remove_by_name(kn, subname);
+}
+
 /*
  * Remove all subdirectories of mon_data of ctrl_mon groups
- * and monitor groups with given domain id.
+ * and monitor groups for the given domain.
+ * Remove files and directories containing "sum" of domain data
+ * when last domain being summed is removed.
  */
 static void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
-					   unsigned int dom_id)
+					   struct rdt_mon_domain *d)
 {
 	struct rdtgroup *prgrp, *crgrp;
+	char subname[32];
+	bool snc_mode;
 	char name[32];
 
+	snc_mode = r->mon_scope == RESCTRL_L3_NODE;
+	sprintf(name, "mon_%s_%02d", r->name, snc_mode ? d->ci->id : d->hdr.id);
+	if (snc_mode)
+		sprintf(subname, "mon_sub_%s_%02d", r->name, d->hdr.id);
+
 	list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
-		sprintf(name, "mon_%s_%02d", r->name, dom_id);
-		kernfs_remove_by_name(prgrp->mon.mon_data_kn, name);
+		mon_rmdir_one_subdir(prgrp->mon.mon_data_kn, name, subname);
 
 		list_for_each_entry(crgrp, &prgrp->mon.crdtgrp_list, mon.crdtgrp_list)
-			kernfs_remove_by_name(crgrp->mon.mon_data_kn, name);
+			mon_rmdir_one_subdir(crgrp->mon.mon_data_kn, name, subname);
 	}
 }
 
@@ -3991,7 +4014,7 @@ void resctrl_offline_mon_domain(struct rdt_resource *r, struct rdt_mon_domain *d
 	 * per domain monitor data directories.
 	 */
 	if (resctrl_mounted && resctrl_arch_mon_capable())
-		rmdir_mondata_subdir_allrdtgrp(r, d->hdr.id);
+		rmdir_mondata_subdir_allrdtgrp(r, d);
 
 	if (is_mbm_enabled())
 		cancel_delayed_work(&d->mbm_over);