From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
John Kacur <jkacur@redhat.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Julia Cartwright <julia@ni.com>,
Daniel Wagner <daniel.wagner@siemens.com>,
tom.zanussi@linux.intel.com, stable-rt@vger.kernel.org,
Alexander Stein <alexander.stein@systec-electronic.com>
Subject: [PATCH RT 03/24] squashfs: make use of local lock in multi_cpu decompressor
Date: Fri, 07 Sep 2018 16:59:00 -0400 [thread overview]
Message-ID: <20180907205930.221592760@goodmis.org> (raw)
In-Reply-To: 20180907205857.262840394@goodmis.org
4.14.63-rt41-rc2 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Julia Cartwright <julia@ni.com>
[ Upstream commit c160736542d7b3d67da32848d2f028b8e35730e5 ]
Currently, the squashfs multi_cpu decompressor makes use of
get_cpu_ptr()/put_cpu_ptr(), which unconditionally disable preemption
during decompression.
Because the workload is distributed across CPUs, all CPUs can observe a
very high wakeup latency, which has been seen to be as much as 8000us.
Convert this decompressor to make use of a local lock, which will allow
execution of the decompressor with preemption-enabled, but also ensure
concurrent accesses to the percpu compressor data on the local CPU will
be serialized.
Cc: stable-rt@vger.kernel.org
Reported-by: Alexander Stein <alexander.stein@systec-electronic.com>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Julia Cartwright <julia@ni.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
fs/squashfs/decompressor_multi_percpu.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/fs/squashfs/decompressor_multi_percpu.c b/fs/squashfs/decompressor_multi_percpu.c
index 23a9c28ad8ea..6a73c4fa88e7 100644
--- a/fs/squashfs/decompressor_multi_percpu.c
+++ b/fs/squashfs/decompressor_multi_percpu.c
@@ -10,6 +10,7 @@
#include <linux/slab.h>
#include <linux/percpu.h>
#include <linux/buffer_head.h>
+#include <linux/locallock.h>
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
@@ -25,6 +26,8 @@ struct squashfs_stream {
void *stream;
};
+static DEFINE_LOCAL_IRQ_LOCK(stream_lock);
+
void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
void *comp_opts)
{
@@ -79,10 +82,15 @@ int squashfs_decompress(struct squashfs_sb_info *msblk, struct buffer_head **bh,
{
struct squashfs_stream __percpu *percpu =
(struct squashfs_stream __percpu *) msblk->stream;
- struct squashfs_stream *stream = get_cpu_ptr(percpu);
- int res = msblk->decompressor->decompress(msblk, stream->stream, bh, b,
- offset, length, output);
- put_cpu_ptr(stream);
+ struct squashfs_stream *stream;
+ int res;
+
+ stream = get_locked_ptr(stream_lock, percpu);
+
+ res = msblk->decompressor->decompress(msblk, stream->stream, bh, b,
+ offset, length, output);
+
+ put_locked_ptr(stream_lock, stream);
if (res < 0)
ERROR("%s decompression failed, data probably corrupt\n",
--
2.18.0
next prev parent reply other threads:[~2018-09-07 21:01 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-07 20:58 [PATCH RT 00/24] Linux 4.14.63-rt41-rc2 Steven Rostedt
2018-09-07 20:58 ` [PATCH RT 01/24] sched/fair: Fix CFS bandwidth control lockdep DEADLOCK report Steven Rostedt
2018-09-07 20:58 ` [PATCH RT 02/24] locallock: provide {get,put}_locked_ptr() variants Steven Rostedt
2018-09-07 20:59 ` Steven Rostedt [this message]
2018-09-07 20:59 ` [PATCH RT 04/24] PM / suspend: Prevent might sleep splats (updated) Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 05/24] PM / wakeup: Make events_lock a RAW_SPINLOCK Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 06/24] PM / s2idle: Make s2idle_wait_head swait based Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 07/24] seqlock: provide the same ordering semantics as mainline Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 08/24] Revert "x86: UV: raw_spinlock conversion" Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 09/24] Revert "timer: delay waking softirqs from the jiffy tick" Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 10/24] irqchip/gic-v3-its: Make its_lock a raw_spin_lock_t Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 11/24] sched/migrate_disable: fallback to preempt_disable() instead barrier() Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 12/24] irqchip/gic-v3-its: Move ITS ->pend_page allocation into an early CPU up hook Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 13/24] irqchip/gic-v3-its: Move pending table allocation to init time Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 14/24] x86/ioapic: Dont let setaffinity unmask threaded EOI interrupt too early Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 15/24] efi: Allow efi=runtime Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 16/24] efi: Disable runtime services on RT Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 17/24] crypto: cryptd - add a lock instead preempt_disable/local_bh_disable Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 18/24] crypto: scompress - serialize RT percpu scratch buffer access with a local lock Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 19/24] sched/core: Avoid __schedule() being called twice in a row Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 20/24] Revert "arm64/xen: Make XEN depend on !RT" Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 21/24] sched: Allow pinned user tasks to be awakened to the CPU they pinned Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 23/24] Revert "softirq: keep the softirq pending check RT-only" Steven Rostedt
2018-09-07 20:59 ` [PATCH RT 24/24] Linux 4.14.63-rt41-rc2 Steven Rostedt
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