LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: "tip-bot2 for Babu Moger" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: pawel.szulik@intel.com, Babu Moger <Babu.Moger@amd.com>,
	Borislav Petkov <bp@suse.de>,
	Reinette Chatre <reinette.chatre@intel.com>,
	stable@vger.kernel.org, x86@kernel.org,
	linux-kernel@vger.kernel.org
Subject: [tip: x86/urgent] x86/resctrl: Fix default monitoring groups reporting
Date: Thu, 12 Aug 2021 18:20:21 -0000	[thread overview]
Message-ID: <162879242193.395.18004814397189147411.tip-bot2@tip-bot2> (raw)
In-Reply-To: <162793309296.9224.15871659871696482080.stgit@bmoger-ubuntu>

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

Commit-ID:     064855a69003c24bd6b473b367d364e418c57625
Gitweb:        https://git.kernel.org/tip/064855a69003c24bd6b473b367d364e418c57625
Author:        Babu Moger <Babu.Moger@amd.com>
AuthorDate:    Mon, 02 Aug 2021 14:38:58 -05:00
Committer:     Borislav Petkov <bp@suse.de>
CommitterDate: Thu, 12 Aug 2021 20:12:20 +02:00

x86/resctrl: Fix default monitoring groups reporting

Creating a new sub monitoring group in the root /sys/fs/resctrl leads to
getting the "Unavailable" value for mbm_total_bytes and mbm_local_bytes
on the entire filesystem.

Steps to reproduce:

  1. mount -t resctrl resctrl /sys/fs/resctrl/

  2. cd /sys/fs/resctrl/

  3. cat mon_data/mon_L3_00/mbm_total_bytes
     23189832

  4. Create sub monitor group:
  mkdir mon_groups/test1

  5. cat mon_data/mon_L3_00/mbm_total_bytes
     Unavailable

When a new monitoring group is created, a new RMID is assigned to the
new group. But the RMID is not active yet. When the events are read on
the new RMID, it is expected to report the status as "Unavailable".

When the user reads the events on the default monitoring group with
multiple subgroups, the events on all subgroups are consolidated
together. Currently, if any of the RMID reads report as "Unavailable",
then everything will be reported as "Unavailable".

Fix the issue by discarding the "Unavailable" reads and reporting all
the successful RMID reads. This is not a problem on Intel systems as
Intel reports 0 on Inactive RMIDs.

Fixes: d89b7379015f ("x86/intel_rdt/cqm: Add mon_data")
Reported-by: Paweł Szulik <pawel.szulik@intel.com>
Signed-off-by: Babu Moger <Babu.Moger@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Cc: stable@vger.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=213311
Link: https://lkml.kernel.org/r/162793309296.9224.15871659871696482080.stgit@bmoger-ubuntu
---
 arch/x86/kernel/cpu/resctrl/monitor.c | 27 ++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index f07c10b..57e4bb6 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -285,15 +285,14 @@ static u64 mbm_overflow_count(u64 prev_msr, u64 cur_msr, unsigned int width)
 	return chunks >>= shift;
 }
 
-static int __mon_event_count(u32 rmid, struct rmid_read *rr)
+static u64 __mon_event_count(u32 rmid, struct rmid_read *rr)
 {
 	struct mbm_state *m;
 	u64 chunks, tval;
 
 	tval = __rmid_read(rmid, rr->evtid);
 	if (tval & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL)) {
-		rr->val = tval;
-		return -EINVAL;
+		return tval;
 	}
 	switch (rr->evtid) {
 	case QOS_L3_OCCUP_EVENT_ID:
@@ -305,12 +304,6 @@ static int __mon_event_count(u32 rmid, struct rmid_read *rr)
 	case QOS_L3_MBM_LOCAL_EVENT_ID:
 		m = &rr->d->mbm_local[rmid];
 		break;
-	default:
-		/*
-		 * Code would never reach here because
-		 * an invalid event id would fail the __rmid_read.
-		 */
-		return -EINVAL;
 	}
 
 	if (rr->first) {
@@ -361,23 +354,29 @@ void mon_event_count(void *info)
 	struct rdtgroup *rdtgrp, *entry;
 	struct rmid_read *rr = info;
 	struct list_head *head;
+	u64 ret_val;
 
 	rdtgrp = rr->rgrp;
 
-	if (__mon_event_count(rdtgrp->mon.rmid, rr))
-		return;
+	ret_val = __mon_event_count(rdtgrp->mon.rmid, rr);
 
 	/*
-	 * For Ctrl groups read data from child monitor groups.
+	 * For Ctrl groups read data from child monitor groups and
+	 * add them together. Count events which are read successfully.
+	 * Discard the rmid_read's reporting errors.
 	 */
 	head = &rdtgrp->mon.crdtgrp_list;
 
 	if (rdtgrp->type == RDTCTRL_GROUP) {
 		list_for_each_entry(entry, head, mon.crdtgrp_list) {
-			if (__mon_event_count(entry->mon.rmid, rr))
-				return;
+			if (__mon_event_count(entry->mon.rmid, rr) == 0)
+				ret_val = 0;
 		}
 	}
+
+	/* Report error if none of rmid_reads are successful */
+	if (ret_val)
+		rr->val = ret_val;
 }
 
 /*

      reply	other threads:[~2021-08-12 18:20 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02 19:38 [PATCH v2] " Babu Moger
2021-08-12 18:20 ` tip-bot2 for Babu Moger [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=162879242193.395.18004814397189147411.tip-bot2@tip-bot2 \
    --to=tip-bot2@linutronix.de \
    --cc=Babu.Moger@amd.com \
    --cc=bp@suse.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-tip-commits@vger.kernel.org \
    --cc=pawel.szulik@intel.com \
    --cc=reinette.chatre@intel.com \
    --cc=stable@vger.kernel.org \
    --cc=x86@kernel.org \
    --subject='Re: [tip: x86/urgent] x86/resctrl: Fix default monitoring groups reporting' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).