* [PATCH RT 01/10] timers: wakeup all timer waiters
2016-09-22 23:17 [PATCH RT 00/10] Linux 3.18.42-rt45-rc1 Steven Rostedt
@ 2016-09-22 23:17 ` Steven Rostedt
2016-09-22 23:17 ` [PATCH RT 02/10] timers: wakeup all timer waiters without holding the base lock Steven Rostedt
` (8 subsequent siblings)
9 siblings, 0 replies; 14+ messages in thread
From: Steven Rostedt @ 2016-09-22 23:17 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Paul Gortmaker, stable-rt
[-- Attachment #1: 0001-timers-wakeup-all-timer-waiters.patch --]
[-- Type: text/plain, Size: 1391 bytes --]
3.18.42-rt45-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
The base lock is dropped during the invocation if the timer. That means
it is possible that we have one waiter while timer1 is running and once
this one finished, we get another waiter while timer2 is running. Since
we wake up only one waiter it is possible that we miss the other one.
This will probably heal itself over time because most of the time we
complete timers without an active wake up.
To avoid the scenario where we don't wake up all waiters at once,
wake_up_all() is used.
Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/time/timer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 12d071d9063e..495de6337357 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1023,7 +1023,7 @@ static void wait_for_running_timer(struct timer_list *timer)
base->running_timer != timer);
}
-# define wakeup_timer_waiters(b) wake_up(&(b)->wait_for_running_timer)
+# define wakeup_timer_waiters(b) wake_up_all(&(b)->wait_for_running_timer)
#else
static inline void wait_for_running_timer(struct timer_list *timer)
{
--
2.8.1
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH RT 02/10] timers: wakeup all timer waiters without holding the base lock
2016-09-22 23:17 [PATCH RT 00/10] Linux 3.18.42-rt45-rc1 Steven Rostedt
2016-09-22 23:17 ` [PATCH RT 01/10] timers: wakeup all timer waiters Steven Rostedt
@ 2016-09-22 23:17 ` Steven Rostedt
2016-09-22 23:17 ` [PATCH RT 03/10] sched: lazy_preempt: avoid a warning in the !RT case Steven Rostedt
` (7 subsequent siblings)
9 siblings, 0 replies; 14+ messages in thread
From: Steven Rostedt @ 2016-09-22 23:17 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Paul Gortmaker, stable-rt
[-- Attachment #1: 0002-timers-wakeup-all-timer-waiters-without-holding-the-.patch --]
[-- Type: text/plain, Size: 955 bytes --]
3.18.42-rt45-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
There should be no need to hold the base lock during the wakeup. There
should be no boosting involved, the wakeup list has its own lock so it
should be safe to do this without the lock.
Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/time/timer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 495de6337357..0df5cbfbcb5b 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1281,8 +1281,8 @@ static inline void __run_timers(struct tvec_base *base)
}
}
}
- wakeup_timer_waiters(base);
spin_unlock_irq(&base->lock);
+ wakeup_timer_waiters(base);
}
#ifdef CONFIG_NO_HZ_COMMON
--
2.8.1
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH RT 03/10] sched: lazy_preempt: avoid a warning in the !RT case
2016-09-22 23:17 [PATCH RT 00/10] Linux 3.18.42-rt45-rc1 Steven Rostedt
2016-09-22 23:17 ` [PATCH RT 01/10] timers: wakeup all timer waiters Steven Rostedt
2016-09-22 23:17 ` [PATCH RT 02/10] timers: wakeup all timer waiters without holding the base lock Steven Rostedt
@ 2016-09-22 23:17 ` Steven Rostedt
2016-09-22 23:17 ` [PATCH RT 04/10] scsi/fcoe: Fix get_cpu()/put_cpu_light() imbalance in fcoe_recv_frame() Steven Rostedt
` (6 subsequent siblings)
9 siblings, 0 replies; 14+ messages in thread
From: Steven Rostedt @ 2016-09-22 23:17 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Paul Gortmaker
[-- Attachment #1: 0003-sched-lazy_preempt-avoid-a-warning-in-the-RT-case.patch --]
[-- Type: text/plain, Size: 698 bytes --]
3.18.42-rt45-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/sched/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 371fa38784e0..ce6d5c6ba8f7 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3171,7 +3171,7 @@ static __always_inline int preemptible_lazy(void)
#else
-static int preemptible_lazy(void)
+static inline int preemptible_lazy(void)
{
return 1;
}
--
2.8.1
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH RT 04/10] scsi/fcoe: Fix get_cpu()/put_cpu_light() imbalance in fcoe_recv_frame()
2016-09-22 23:17 [PATCH RT 00/10] Linux 3.18.42-rt45-rc1 Steven Rostedt
` (2 preceding siblings ...)
2016-09-22 23:17 ` [PATCH RT 03/10] sched: lazy_preempt: avoid a warning in the !RT case Steven Rostedt
@ 2016-09-22 23:17 ` Steven Rostedt
2016-09-22 23:17 ` [PATCH RT 05/10] net: add back the missing serialization in ip_send_unicast_reply() Steven Rostedt
` (5 subsequent siblings)
9 siblings, 0 replies; 14+ messages in thread
From: Steven Rostedt @ 2016-09-22 23:17 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Paul Gortmaker, stable-rt, Mike Gabraith
[-- Attachment #1: 0004-scsi-fcoe-Fix-get_cpu-put_cpu_light-imbalance-in-fco.patch --]
[-- Type: text/plain, Size: 1096 bytes --]
3.18.42-rt45-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Mike Galbraith <umgwanakikbuti@gmail.com>
During master->rt merge, I stumbled across the buglet below.
Fix get_cpu()/put_cpu_light() imbalance.
Cc: stable-rt@vger.kernel.org
Signed-off-by: Mike Gabraith <umgwanakikbuti@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
drivers/scsi/fcoe/fcoe.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c
index c1f2bd0bcdb7..8933c02b6729 100644
--- a/drivers/scsi/fcoe/fcoe.c
+++ b/drivers/scsi/fcoe/fcoe.c
@@ -1816,7 +1816,7 @@ static void fcoe_recv_frame(struct sk_buff *skb)
*/
hp = (struct fcoe_hdr *) skb_network_header(skb);
- stats = per_cpu_ptr(lport->stats, get_cpu());
+ stats = per_cpu_ptr(lport->stats, get_cpu_light());
if (unlikely(FC_FCOE_DECAPS_VER(hp) != FC_FCOE_VER)) {
if (stats->ErrorFrames < 5)
printk(KERN_WARNING "fcoe: FCoE version "
--
2.8.1
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH RT 05/10] net: add back the missing serialization in ip_send_unicast_reply()
2016-09-22 23:17 [PATCH RT 00/10] Linux 3.18.42-rt45-rc1 Steven Rostedt
` (3 preceding siblings ...)
2016-09-22 23:17 ` [PATCH RT 04/10] scsi/fcoe: Fix get_cpu()/put_cpu_light() imbalance in fcoe_recv_frame() Steven Rostedt
@ 2016-09-22 23:17 ` Steven Rostedt
2016-09-22 23:17 ` [PATCH RT 06/10] net: add a lock around icmp_sk() Steven Rostedt
` (4 subsequent siblings)
9 siblings, 0 replies; 14+ messages in thread
From: Steven Rostedt @ 2016-09-22 23:17 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Paul Gortmaker, stable-rt
[-- Attachment #1: 0005-net-add-back-the-missing-serialization-in-ip_send_un.patch --]
[-- Type: text/plain, Size: 3632 bytes --]
3.18.42-rt45-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Some time ago Sami Pietikainen reported a crash on -RT in
ip_send_unicast_reply() which was later fixed by Nicholas Mc Guire
(v3.12.8-rt11). Later (v3.18.8) the code was reworked and I dropped the
patch. As it turns out it was mistake.
I have reports that the same crash is possible with a similar backtrace.
It seems that vanilla protects access to this_cpu_ptr() via
local_bh_disable(). This does not work the on -RT since we can have
NET_RX and NET_TX running in parallel on the same CPU.
This is brings back the old locks.
|Unable to handle kernel NULL pointer dereference at virtual address 00000010
|PC is at __ip_make_skb+0x198/0x3e8
|[<c04e39d8>] (__ip_make_skb) from [<c04e3ca8>] (ip_push_pending_frames+0x20/0x40)
|[<c04e3ca8>] (ip_push_pending_frames) from [<c04e3ff0>] (ip_send_unicast_reply+0x210/0x22c)
|[<c04e3ff0>] (ip_send_unicast_reply) from [<c04fbb54>] (tcp_v4_send_reset+0x190/0x1c0)
|[<c04fbb54>] (tcp_v4_send_reset) from [<c04fcc1c>] (tcp_v4_do_rcv+0x22c/0x288)
|[<c04fcc1c>] (tcp_v4_do_rcv) from [<c0474364>] (release_sock+0xb4/0x150)
|[<c0474364>] (release_sock) from [<c04ed904>] (tcp_close+0x240/0x454)
|[<c04ed904>] (tcp_close) from [<c0511408>] (inet_release+0x74/0x7c)
|[<c0511408>] (inet_release) from [<c0470728>] (sock_release+0x30/0xb0)
|[<c0470728>] (sock_release) from [<c0470abc>] (sock_close+0x1c/0x24)
|[<c0470abc>] (sock_close) from [<c0115ec4>] (__fput+0xe8/0x20c)
|[<c0115ec4>] (__fput) from [<c0116050>] (____fput+0x18/0x1c)
|[<c0116050>] (____fput) from [<c0058138>] (task_work_run+0xa4/0xb8)
|[<c0058138>] (task_work_run) from [<c0011478>] (do_work_pending+0xd0/0xe4)
|[<c0011478>] (do_work_pending) from [<c000e740>] (work_pending+0xc/0x20)
|Code: e3530001 8a000001 e3a00040 ea000011 (e5973010)
Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
net/ipv4/tcp_ipv4.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 5d5390299277..7a9139da3854 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -62,6 +62,7 @@
#include <linux/init.h>
#include <linux/times.h>
#include <linux/slab.h>
+#include <linux/locallock.h>
#include <net/net_namespace.h>
#include <net/icmp.h>
@@ -562,6 +563,7 @@ void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
}
EXPORT_SYMBOL(tcp_v4_send_check);
+static DEFINE_LOCAL_IRQ_LOCK(tcp_sk_lock);
/*
* This routine will send an RST to the other tcp.
*
@@ -683,10 +685,13 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
arg.bound_dev_if = sk->sk_bound_dev_if;
arg.tos = ip_hdr(skb)->tos;
+
+ local_lock(tcp_sk_lock);
ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
skb, &TCP_SKB_CB(skb)->header.h4.opt,
ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
&arg, arg.iov[0].iov_len);
+ local_unlock(tcp_sk_lock);
TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
@@ -768,10 +773,12 @@ static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
if (oif)
arg.bound_dev_if = oif;
arg.tos = tos;
+ local_lock(tcp_sk_lock);
ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
skb, &TCP_SKB_CB(skb)->header.h4.opt,
ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
&arg, arg.iov[0].iov_len);
+ local_unlock(tcp_sk_lock);
TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
}
--
2.8.1
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH RT 06/10] net: add a lock around icmp_sk()
2016-09-22 23:17 [PATCH RT 00/10] Linux 3.18.42-rt45-rc1 Steven Rostedt
` (4 preceding siblings ...)
2016-09-22 23:17 ` [PATCH RT 05/10] net: add back the missing serialization in ip_send_unicast_reply() Steven Rostedt
@ 2016-09-22 23:17 ` Steven Rostedt
2016-09-22 23:17 ` [PATCH RT 07/10] fs/dcache: resched/chill only if we make no progress Steven Rostedt
` (3 subsequent siblings)
9 siblings, 0 replies; 14+ messages in thread
From: Steven Rostedt @ 2016-09-22 23:17 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Paul Gortmaker, stable-rt
[-- Attachment #1: 0006-net-add-a-lock-around-icmp_sk.patch --]
[-- Type: text/plain, Size: 2369 bytes --]
3.18.42-rt45-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
It looks like the this_cpu_ptr() access in icmp_sk() is protected with
local_bh_disable(). To avoid missing serialization in -RT I am adding
here a local lock. No crash has been observed, this is just precaution.
Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
net/ipv4/icmp.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 3c71d5fc54ea..46571b86e171 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -78,6 +78,7 @@
#include <linux/string.h>
#include <linux/netfilter_ipv4.h>
#include <linux/slab.h>
+#include <linux/locallock.h>
#include <net/snmp.h>
#include <net/ip.h>
#include <net/route.h>
@@ -204,6 +205,8 @@ static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
*
* On SMP we have one ICMP socket per-cpu.
*/
+static DEFINE_LOCAL_IRQ_LOCK(icmp_sk_lock);
+
static struct sock *icmp_sk(struct net *net)
{
return net->ipv4.icmp_sk[smp_processor_id()];
@@ -215,12 +218,14 @@ static inline struct sock *icmp_xmit_lock(struct net *net)
local_bh_disable();
+ local_lock(icmp_sk_lock);
sk = icmp_sk(net);
if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
/* This can happen if the output path signals a
* dst_link_failure() for an outgoing ICMP packet.
*/
+ local_unlock(icmp_sk_lock);
local_bh_enable();
return NULL;
}
@@ -230,6 +235,7 @@ static inline struct sock *icmp_xmit_lock(struct net *net)
static inline void icmp_xmit_unlock(struct sock *sk)
{
spin_unlock_bh(&sk->sk_lock.slock);
+ local_unlock(icmp_sk_lock);
}
int sysctl_icmp_msgs_per_sec __read_mostly = 1000;
@@ -357,6 +363,7 @@ static void icmp_push_reply(struct icmp_bxm *icmp_param,
struct sock *sk;
struct sk_buff *skb;
+ local_lock(icmp_sk_lock);
sk = icmp_sk(dev_net((*rt)->dst.dev));
if (ip_append_data(sk, fl4, icmp_glue_bits, icmp_param,
icmp_param->data_len+icmp_param->head_len,
@@ -379,6 +386,7 @@ static void icmp_push_reply(struct icmp_bxm *icmp_param,
skb->ip_summed = CHECKSUM_NONE;
ip_push_pending_frames(sk, fl4);
}
+ local_unlock(icmp_sk_lock);
}
/*
--
2.8.1
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH RT 07/10] fs/dcache: resched/chill only if we make no progress
2016-09-22 23:17 [PATCH RT 00/10] Linux 3.18.42-rt45-rc1 Steven Rostedt
` (5 preceding siblings ...)
2016-09-22 23:17 ` [PATCH RT 06/10] net: add a lock around icmp_sk() Steven Rostedt
@ 2016-09-22 23:17 ` Steven Rostedt
2016-09-22 23:17 ` [PATCH RT 08/10] x86/preempt-lazy: fixup should_resched() Steven Rostedt
` (2 subsequent siblings)
9 siblings, 0 replies; 14+ messages in thread
From: Steven Rostedt @ 2016-09-22 23:17 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Paul Gortmaker, stable-rt
[-- Attachment #1: 0007-fs-dcache-resched-chill-only-if-we-make-no-progress.patch --]
[-- Type: text/plain, Size: 2442 bytes --]
3.18.42-rt45-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Upstream commit 47be61845c77 ("fs/dcache.c: avoid soft-lockup in
dput()") changed the condition _when_ cpu_relax() / cond_resched() was
invoked. This change was adapted in -RT into mostly the same thing
except that if cond_resched() did nothing we had to do cpu_chill() to
force the task off CPU for a tiny little bit in case the task had RT
priority and did not want to leave the CPU.
This change resulted in a performance regression (in my testcase the
build time on /dev/shm increased from 19min to 24min). The reason is
that with this change cpu_chill() was invoked even dput() made progress
(dentry_kill() returned a different dentry) instead only if we were
trying this operation on the same dentry over and over again.
This patch brings back to the old behavior back to cond_resched() &
chill if we make no progress. A little improvement is to invoke
cpu_chill() only if we are a RT task (and avoid the sleep otherwise).
Otherwise the scheduler should remove us from the CPU if we make no
progress.
Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
fs/dcache.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index 1cb13a024cf8..44a3419c7125 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -39,6 +39,8 @@
#include <linux/prefetch.h>
#include <linux/ratelimit.h>
#include <linux/list_lru.h>
+#include <linux/sched/rt.h>
+#include <linux/sched/deadline.h>
#include "internal.h"
#include "mount.h"
@@ -722,6 +724,8 @@ static inline bool fast_dput(struct dentry *dentry)
*/
void dput(struct dentry *dentry)
{
+ struct dentry *parent;
+
if (unlikely(!dentry))
return;
@@ -758,14 +762,17 @@ repeat:
return;
kill_it:
- dentry = dentry_kill(dentry);
- if (dentry) {
+ parent = dentry_kill(dentry);
+ if (parent) {
int r;
- /* the task with the highest priority won't schedule */
- r = cond_resched();
- if (!r)
- cpu_chill();
+ if (parent == dentry) {
+ /* the task with the highest priority won't schedule */
+ r = cond_resched();
+ if (!r && (rt_task(current) || dl_task(current)))
+ cpu_chill();
+ } else
+ dentry = parent;
goto repeat;
}
}
--
2.8.1
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH RT 08/10] x86/preempt-lazy: fixup should_resched()
2016-09-22 23:17 [PATCH RT 00/10] Linux 3.18.42-rt45-rc1 Steven Rostedt
` (6 preceding siblings ...)
2016-09-22 23:17 ` [PATCH RT 07/10] fs/dcache: resched/chill only if we make no progress Steven Rostedt
@ 2016-09-22 23:17 ` Steven Rostedt
2016-09-22 23:17 ` [PATCH RT 09/10] fs/dcache: incremental fixup of the retry routine Steven Rostedt
2016-09-22 23:17 ` [PATCH RT 10/10] Linux 3.18.42-rt45-rc1 Steven Rostedt
9 siblings, 0 replies; 14+ messages in thread
From: Steven Rostedt @ 2016-09-22 23:17 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Paul Gortmaker
[-- Attachment #1: 0008-x86-preempt-lazy-fixup-should_resched.patch --]
[-- Type: text/plain, Size: 1856 bytes --]
3.18.42-rt45-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
should_resched() returns true if NEED_RESCHED is set and the
preempt_count is 0 _or_ if NEED_RESCHED_LAZY is set ignoring the preempt
counter. Ignoring the preemp counter is wrong. This patch adds this into
account.
While at it, __preempt_count_dec_and_test() ignores preempt_lazy_count
while checking TIF_NEED_RESCHED_LAZY so we this check, too.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
arch/x86/include/asm/preempt.h | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h
index 060d1b4e475d..6806369bddf5 100644
--- a/arch/x86/include/asm/preempt.h
+++ b/arch/x86/include/asm/preempt.h
@@ -95,6 +95,8 @@ static __always_inline bool __preempt_count_dec_and_test(void)
if (____preempt_count_dec_and_test())
return true;
#ifdef CONFIG_PREEMPT_LAZY
+ if (current_thread_info()->preempt_lazy_count)
+ return false;
return test_thread_flag(TIF_NEED_RESCHED_LAZY);
#else
return false;
@@ -107,8 +109,18 @@ static __always_inline bool __preempt_count_dec_and_test(void)
static __always_inline bool should_resched(void)
{
#ifdef CONFIG_PREEMPT_LAZY
- return unlikely(!raw_cpu_read_4(__preempt_count) || \
- test_thread_flag(TIF_NEED_RESCHED_LAZY));
+ u32 tmp;
+
+ if (!raw_cpu_read_4(__preempt_count))
+ return true;
+
+ /* preempt count == 0 ? */
+ tmp &= ~PREEMPT_NEED_RESCHED;
+ if (tmp)
+ return false;
+ if (current_thread_info()->preempt_lazy_count)
+ return false;
+ return test_thread_flag(TIF_NEED_RESCHED_LAZY);
#else
return unlikely(!raw_cpu_read_4(__preempt_count));
#endif
--
2.8.1
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH RT 09/10] fs/dcache: incremental fixup of the retry routine
2016-09-22 23:17 [PATCH RT 00/10] Linux 3.18.42-rt45-rc1 Steven Rostedt
` (7 preceding siblings ...)
2016-09-22 23:17 ` [PATCH RT 08/10] x86/preempt-lazy: fixup should_resched() Steven Rostedt
@ 2016-09-22 23:17 ` Steven Rostedt
2016-09-22 23:17 ` [PATCH RT 10/10] Linux 3.18.42-rt45-rc1 Steven Rostedt
9 siblings, 0 replies; 14+ messages in thread
From: Steven Rostedt @ 2016-09-22 23:17 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Paul Gortmaker
[-- Attachment #1: 0009-fs-dcache-incremental-fixup-of-the-retry-routine.patch --]
[-- Type: text/plain, Size: 1218 bytes --]
3.18.42-rt45-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
It has been pointed out by tglx that on UP the non-RT task could spin
its entire time slice because the lock owner is preempted. This won't
happen on !RT. So we back to "chill" if we can't cond_resched() did not
work.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
fs/dcache.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index 44a3419c7125..986acc945c06 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -39,8 +39,6 @@
#include <linux/prefetch.h>
#include <linux/ratelimit.h>
#include <linux/list_lru.h>
-#include <linux/sched/rt.h>
-#include <linux/sched/deadline.h>
#include "internal.h"
#include "mount.h"
@@ -769,10 +767,11 @@ kill_it:
if (parent == dentry) {
/* the task with the highest priority won't schedule */
r = cond_resched();
- if (!r && (rt_task(current) || dl_task(current)))
+ if (!r)
cpu_chill();
- } else
+ } else {
dentry = parent;
+ }
goto repeat;
}
}
--
2.8.1
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH RT 10/10] Linux 3.18.42-rt45-rc1
2016-09-22 23:17 [PATCH RT 00/10] Linux 3.18.42-rt45-rc1 Steven Rostedt
` (8 preceding siblings ...)
2016-09-22 23:17 ` [PATCH RT 09/10] fs/dcache: incremental fixup of the retry routine Steven Rostedt
@ 2016-09-22 23:17 ` Steven Rostedt
9 siblings, 0 replies; 14+ messages in thread
From: Steven Rostedt @ 2016-09-22 23:17 UTC (permalink / raw)
To: linux-kernel, linux-rt-users
Cc: Thomas Gleixner, Carsten Emde, Sebastian Andrzej Siewior,
John Kacur, Paul Gortmaker
[-- Attachment #1: 0010-Linux-3.18.42-rt45-rc1.patch --]
[-- Type: text/plain, Size: 412 bytes --]
3.18.42-rt45-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
---
localversion-rt | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/localversion-rt b/localversion-rt
index ac4d836a809d..e6421b58f4c8 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt44
+-rt45-rc1
--
2.8.1
^ permalink raw reply related [flat|nested] 14+ messages in thread