starlingx
/
integ
Code Issues Proposed changes

Backport the fix for deadlock in CFS-bandwidth timer locking 

Low-latency profile of StarlingX is affected by a deadlock in
CFS scheduler. spin_lock is used in IRQ handler there instead of
spin_lock_irqsave. This leads to an attempt to lock the same
spinlock twice and inevitable system freeze. Backporting c0ad4aa4d8
commit from upstream kernel to cure the issue.

Change-Id: I5416c0e0886f42d2bcec8e3e5da063e6af6916f8
Closes-bug: 1832854
Signed-off-by: Alex Kozyrev <alex.kozyrev@windriver.com>
This commit is contained in:
Alex Kozyrev 2019-07-26 13:58:17 -04:00
parent 8a06637f0c
commit 56a91fec13
4 changed files with 188 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/kernel-rt/centos/build_srpm.data
View File

@ -1,4 +1,4 @@
COPY_LIST="files/*"
TIS_PATCH_VER=2
TIS_PATCH_VER=3
BUILD_IS_BIG=11
BUILD_IS_SLOW=12

22
kernel/kernel-rt/centos/meta_patches/Compile-issues.patch
View File

@ -1,9 +1,9 @@
From 8fbd0edbcf6ed51b9e58d267d0ce7b40f00118a1 Mon Sep 17 00:00:00 2001
From: Bart Wensley <barton.wensley@windriver.com>
Date: Tue, 9 Jul 2019 07:18:00 -0500
From 6fe892d415b3d728d223069eacb6f291fc38d86d Mon Sep 17 00:00:00 2001
From: Alex Kozyrev <alex.kozyrev@windriver.com>
Date: Mon, 29 Jul 2019 11:48:51 -0400
Subject: [PATCH 1/1] Compile issues
Signed-off-by: Bart Wensley <barton.wensley@windriver.com>
Signed-off-by: Alex Kozyrev <alex.kozyrev@windriver.com>
---
SPECS/kernel-rt.spec | 8 ++++++++
1 file changed, 8 insertions(+)
@ -12,22 +12,22 @@ diff --git a/SPECS/kernel-rt.spec b/SPECS/kernel-rt.spec
index 3b7985c..5025db7 100644
--- a/SPECS/kernel-rt.spec
+++ b/SPECS/kernel-rt.spec
@@ -418,6 +418,11 @@ Patch1027: dpt_i2o-fix-build-warning.patch
# DRBD was choking on write same
@@ -418,6 +418,11 @@ # DRBD was choking on write same
Patch1028: turn-off-write-same-in-smartqpi-driver.patch
Patch1029: restrict-iSCSI-kthreads-to-CPUs-in-cpu_kthread_mask.patch
+Patch1030: fix-compilation-issues.patch
Patch1030: robustify-CFS-bandwidth-timer-locking.patch
+Patch1031: fix-compilation-issues.patch
+# Fix CentOS 7.6 upgrade compile error
+Patch1031: fix-CentOS-7.6-upgrade-compile-error.patch
+Patch1032: fix-CentOS-7.6-upgrade-compile-error.patch
+# Compile fix for disabling CONFIG_MEMCG_KMEM
+Patch1032: compile-fix-for-disabling-CONFIG_MEMCG_KMEM.patch
+Patch1033: compile-fix-for-disabling-CONFIG_MEMCG_KMEM.patch
BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root
@@ -780,6 +785,9 @@ ApplyPatch aic94xx-Skip-reading-user-settings-if-flash-is-not-f.patch
ApplyPatch dpt_i2o-fix-build-warning.patch
@@ -781,6 +786,9 @@ ApplyPatch dpt_i2o-fix-build-warning.patch
ApplyPatch turn-off-write-same-in-smartqpi-driver.patch
ApplyPatch restrict-iSCSI-kthreads-to-CPUs-in-cpu_kthread_mask.patch
ApplyPatch robustify-CFS-bandwidth-timer-locking.patch
+ApplyPatch fix-compilation-issues.patch
+ApplyPatch fix-CentOS-7.6-upgrade-compile-error.patch
+ApplyPatch compile-fix-for-disabling-CONFIG_MEMCG_KMEM.patch

21
kernel/kernel-rt/centos/meta_patches/Kernel-source-patches-for-TiC.patch
View File

@ -1,21 +1,18 @@
From 4412b4d092c2f38feed1d0f8ea1a69c799315663 Mon Sep 17 00:00:00 2001
Message-Id: <4412b4d092c2f38feed1d0f8ea1a69c799315663.1528227675.git.Jim.Somerville@windriver.com>
In-Reply-To: <dc53b79fa7cf0faa28e58d72ef4b34d405b469c0.1528227674.git.Jim.Somerville@windriver.com>
References: <dc53b79fa7cf0faa28e58d72ef4b34d405b469c0.1528227674.git.Jim.Somerville@windriver.com>
From: Jim Somerville <Jim.Somerville@windriver.com>
Date: Mon, 23 Apr 2018 15:19:36 -0400
From 6a04eb3881ccb3c592b4b47d36bde90f1e33c598 Mon Sep 17 00:00:00 2001
From: Alex Kozyrev <alex.kozyrev@windriver.com>
Date: Mon, 29 Jul 2019 11:48:49 -0400
Subject: [PATCH 2/3] Kernel source patches for TiC
Signed-off-by: Jim Somerville <Jim.Somerville@windriver.com>
Signed-off-by: Alex Kozyrev <alex.kozyrev@windriver.com>
---
SPECS/kernel-rt.spec | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 62 insertions(+)
SPECS/kernel-rt.spec | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 64 insertions(+)
diff --git a/SPECS/kernel-rt.spec b/SPECS/kernel-rt.spec
index 905ae52..15114e6 100644
--- a/SPECS/kernel-rt.spec
+++ b/SPECS/kernel-rt.spec
@@ -386,6 +386,38 @@ Source1000: modprobe-dccp-blacklist.conf
@@ -386,6 +386,39 @@ Source1000: modprobe-dccp-blacklist.conf
# Empty final patch file to facilitate testing of kernel patches
Patch999999: linux-kernel-test.patch
@ -51,10 +48,11 @@ index 905ae52..15114e6 100644
+# DRBD was choking on write same
+Patch1028: turn-off-write-same-in-smartqpi-driver.patch
+Patch1029: restrict-iSCSI-kthreads-to-CPUs-in-cpu_kthread_mask.patch
+Patch1030: robustify-CFS-bandwidth-timer-locking.patch
BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root
@@ -718,6 +750,36 @@ cp %{SOURCE38} .
@@ -718,6 +751,37 @@ cp %{SOURCE38} .
## Apply Patches here
ApplyPatch linux-kernel-test.patch
@ -88,6 +86,7 @@ index 905ae52..15114e6 100644
+ApplyPatch dpt_i2o-fix-build-warning.patch
+ApplyPatch turn-off-write-same-in-smartqpi-driver.patch
+ApplyPatch restrict-iSCSI-kthreads-to-CPUs-in-cpu_kthread_mask.patch
+ApplyPatch robustify-CFS-bandwidth-timer-locking.patch
# move off upstream version mechanism
if [ -e localversion-rt ]; then

166
kernel/kernel-rt/centos/patches/robustify-CFS-bandwidth-timer-locking.patch Normal file
View File

@ -0,0 +1,166 @@
From c0ad4aa4d8416a39ad262a2bd68b30acd951bf0e Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Mon, 7 Jan 2019 13:52:31 +0100
Subject: sched/fair: Robustify CFS-bandwidth timer locking
Traditionally hrtimer callbacks were run with IRQs disabled, but with
the introduction of HRTIMER_MODE_SOFT it is possible they run from
SoftIRQ context, which does _NOT_ have IRQs disabled.
Allow for the CFS bandwidth timers (period_timer and slack_timer) to
be ran from SoftIRQ context; this entails removing the assumption that
IRQs are already disabled from the locking.
While mainline doesn't strictly need this, -RT forces all timers not
explicitly marked with MODE_HARD into MODE_SOFT and trips over this.
And marking these timers as MODE_HARD doesn't make sense as they're
not required for RT operation and can potentially be quite expensive.
Reported-by: Tom Putzeys <tom.putzeys@be.atlascopco.com>
Tested-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190107125231.GE14122@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Alex Kozyrev <alex.kozyrev@windriver.com>
---
kernel/sched/fair.c | 33 ++++++++++++++++++---------------
1 file changed, 18 insertions(+), 15 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d3d746b..e9a8d95 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3488,13 +3488,14 @@ static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b,
struct cfs_rq *cfs_rq;
u64 runtime;
u64 starting_runtime = remaining;
+ unsigned long flags;
rcu_read_lock();
list_for_each_entry_rcu(cfs_rq, &cfs_b->throttled_cfs_rq,
throttled_list) {
struct rq *rq = rq_of(cfs_rq);
- raw_spin_lock(&rq->lock);
+ raw_spin_lock_irqsave(&rq->lock, flags);
if (!cfs_rq_throttled(cfs_rq))
goto next;
@@ -3511,7 +3512,7 @@ static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b,
unthrottle_cfs_rq(cfs_rq);
next:
- raw_spin_unlock(&rq->lock);
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
if (!remaining)
break;
@@ -3527,7 +3528,7 @@ next:
* period the timer is deactivated until scheduling resumes; cfs_b->idle is
* used to track this state.
*/
-static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
+static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun, unsigned long flags)
{
u64 runtime, runtime_expires;
int throttled;
@@ -3576,11 +3577,11 @@ static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
while (throttled && cfs_b->runtime > 0 && !cfs_b->distribute_running) {
runtime = cfs_b->runtime;
cfs_b->distribute_running = 1;
- raw_spin_unlock(&cfs_b->lock);
+ raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
/* we can't nest cfs_b->lock while distributing bandwidth */
runtime = distribute_cfs_runtime(cfs_b, runtime,
runtime_expires);
- raw_spin_lock(&cfs_b->lock);
+ raw_spin_lock_irqsave(&cfs_b->lock, flags);
cfs_b->distribute_running = 0;
throttled = !list_empty(&cfs_b->throttled_cfs_rq);
@@ -3689,17 +3690,18 @@ static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq)
static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
{
u64 runtime = 0, slice = sched_cfs_bandwidth_slice();
+ unsigned long flags;
u64 expires;
/* confirm we're still not at a refresh boundary */
- raw_spin_lock(&cfs_b->lock);
+ raw_spin_lock_irqsave(&cfs_b->lock, flags);
if (cfs_b->distribute_running) {
- raw_spin_unlock(&cfs_b->lock);
+ raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
return;
}
if (runtime_refresh_within(cfs_b, min_bandwidth_expiration)) {
- raw_spin_unlock(&cfs_b->lock);
+ raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
return;
}
@@ -3710,18 +3712,18 @@ static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
if (runtime)
cfs_b->distribute_running = 1;
- raw_spin_unlock(&cfs_b->lock);
+ raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
if (!runtime)
return;
runtime = distribute_cfs_runtime(cfs_b, runtime, expires);
- raw_spin_lock(&cfs_b->lock);
+ raw_spin_lock_irqsave(&cfs_b->lock, flags);
if (expires == cfs_b->runtime_expires)
cfs_b->runtime -= min(runtime, cfs_b->runtime);
cfs_b->distribute_running = 0;
- raw_spin_unlock(&cfs_b->lock);
+ raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
}
/*
@@ -3785,7 +3787,7 @@ static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq)
}
static inline u64 default_cfs_period(void);
-static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun);
+static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrunn, unsigned long flags);
static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b);
static enum hrtimer_restart sched_cfs_slack_timer(struct hrtimer *timer)
@@ -3802,10 +3804,11 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
struct cfs_bandwidth *cfs_b =
container_of(timer, struct cfs_bandwidth, period_timer);
ktime_t now;
+ unsigned long flags;
int overrun;
int idle = 0;
- raw_spin_lock(&cfs_b->lock);
+ raw_spin_lock_irqsave(&cfs_b->lock, flags);
for (;;) {
now = hrtimer_cb_get_time(timer);
overrun = hrtimer_forward(timer, now, cfs_b->period);
@@ -3813,9 +3816,9 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
if (!overrun)
break;
- idle = do_sched_cfs_period_timer(cfs_b, overrun);
+ idle = do_sched_cfs_period_timer(cfs_b, overrun, flags);
}
- raw_spin_unlock(&cfs_b->lock);
+ raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
}
--
1.8.3.1