From: zanussi@kernel.org
To: LKML <linux-kernel@vger.kernel.org>,
linux-rt-users <linux-rt-users@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>, John Kacur <jkacur@redhat.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Daniel Wagner <wagi@monom.org>, Tom Zanussi <zanussi@kernel.org>
Subject: [PATCH RT 7/8] tracing: make preempt_lazy and migrate_disable counter smaller
Date: Mon, 9 Mar 2020 14:47:52 -0500 [thread overview]
Message-ID: <0012457a5fe618e36a20b4d1b27265be51c6e8b1.1583783251.git.zanussi@kernel.org> (raw)
In-Reply-To: <cover.1583783251.git.zanussi@kernel.org>
In-Reply-To: <cover.1583783251.git.zanussi@kernel.org>
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
v4.14.172-rt78-rc1 stable review patch.
If anyone has any objections, please let me know.
-----------
[ Upstream commit dd430bf5ecb40f9a89679c85868826475d71de54 ]
The migrate_disable counter should not exceed 255 so it is enough to
store it in an 8bit field.
With this change we can move the `preempt_lazy_count' member into the
gap so the whole struct shrinks by 4 bytes to 12 bytes in total.
Remove the `padding' field, it is not needed.
Update the tracing fields in trace_define_common_fields() (it was
missing the preempt_lazy_count field).
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
---
include/linux/trace_events.h | 3 +--
kernel/trace/trace_events.c | 4 ++--
2 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index edd1e42e8a2f7..01e9ab3107531 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -62,8 +62,7 @@ struct trace_entry {
unsigned char flags;
unsigned char preempt_count;
int pid;
- unsigned short migrate_disable;
- unsigned short padding;
+ unsigned char migrate_disable;
unsigned char preempt_lazy_count;
};
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 60e371451ec31..edd43841c94ad 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -187,8 +187,8 @@ static int trace_define_common_fields(void)
__common_field(unsigned char, flags);
__common_field(unsigned char, preempt_count);
__common_field(int, pid);
- __common_field(unsigned short, migrate_disable);
- __common_field(unsigned short, padding);
+ __common_field(unsigned char, migrate_disable);
+ __common_field(unsigned char, preempt_lazy_count);
return ret;
}
--
2.14.1
next prev parent reply other threads:[~2020-03-09 19:48 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-09 19:47 [PATCH RT 0/8] Linux v4.14.172-rt78-rc1 zanussi
2020-03-09 19:47 ` [PATCH RT 1/8] userfaultfd: Use a seqlock instead of seqcount zanussi
2020-03-09 19:47 ` [PATCH RT 2/8] sched: migrate_enable: Use per-cpu cpu_stop_work zanussi
2020-03-09 19:47 ` [PATCH RT 3/8] sched: migrate_enable: Remove __schedule() call zanussi
2020-03-09 19:47 ` [PATCH RT 4/8] mm/memcontrol: Move misplaced local_unlock_irqrestore() zanussi
2020-03-09 19:47 ` [PATCH RT 5/8] locallock: Include header for the `current' macro zanussi
2020-03-09 19:47 ` [PATCH RT 6/8] drm/vmwgfx: Drop preempt_disable() in vmw_fifo_ping_host() zanussi
2020-03-09 19:47 ` zanussi [this message]
2020-03-09 19:47 ` [PATCH RT 8/8] Linux 4.14.172-rt78-rc1 zanussi
-- strict thread matches above, loose matches on Subject: below --
2020-03-06 18:40 [PATCH RT 0/8] Linux 4.19.106-rt45-rc1 Steven Rostedt
2020-03-06 18:40 ` [PATCH RT 7/8] tracing: make preempt_lazy and migrate_disable counter smaller Steven Rostedt
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