From: Yafang Shao <laoar.shao@gmail.com>
To: keescook@chromium.org, rostedt@goodmis.org,
mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com,
pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk,
akpm@linux-foundation.org, valentin.schneider@arm.com,
qiang.zhang@windriver.com, robdclark@chromium.org,
christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com,
juri.lelli@redhat.com, vincent.guittot@linaro.org,
davem@davemloft.net, kuba@kernel.org, ast@kernel.org,
daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com,
songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com,
kpsingh@kernel.org
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, oliver.sang@intel.com,
lkp@intel.com, Yafang Shao <laoar.shao@gmail.com>
Subject: [PATCH v5 14/15] sched.h: extend task comm from 16 to 24 for CONFIG_BASE_FULL
Date: Thu, 21 Oct 2021 03:46:02 +0000 [thread overview]
Message-ID: <20211021034603.4458-5-laoar.shao@gmail.com> (raw)
In-Reply-To: <20211021034603.4458-1-laoar.shao@gmail.com>
When I was implementing a new per-cpu kthread cfs_migration, I found the
comm of it "cfs_migration/%u" is truncated due to the limitation of
TASK_COMM_LEN. For example, the comm of the percpu thread on CPU10~19 are
all with the same name "cfs_migration/1", which will confuse the user. This
issue is not critical, because we can get the corresponding CPU from the
task's Cpus_allowed. But for kthreads correspoinding to other hardware
devices, it is not easy to get the detailed device info from task comm,
for example,
jbd2/nvme0n1p2-
xfs-reclaim/sdf
We can also shorten the name to work around this problem, but I find
there are so many truncated kthreads:
rcu_tasks_kthre
rcu_tasks_rude_
rcu_tasks_trace
poll_mpt3sas0_s
ext4-rsv-conver
xfs-reclaim/sd{a, b, c, ...}
xfs-blockgc/sd{a, b, c, ...}
xfs-inodegc/sd{a, b, c, ...}
audit_send_repl
ecryptfs-kthrea
vfio-irqfd-clea
jbd2/nvme0n1p2-
...
We should improve this problem fundamentally.
This patch extends the size of task comm to 24 bytes, which is the
same length with workqueue's, for the CONFIG_BASE_FULL case. And for the
CONFIG_BASE_SMALL case, the size of task comm is still kept as 16 bytes.
After this patchset, the truncated kthreads listed above will be
displayed as:
rcu_tasks_kthread
rcu_tasks_rude_kthread
rcu_tasks_trace_kthread
poll_mpt3sas0_statu
ext4-rsv-conversion
xfs-reclaim/sdf1
xfs-blockgc/sdf1
xfs-inodegc/sdf1
audit_send_reply
ecryptfs-kthread
vfio-irqfd-cleanup
jbd2/nvme0n1p2-8
Suggested-by: Petr Mladek <pmladek@suse.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Petr Mladek <pmladek@suse.com>
---
include/linux/sched.h | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 62d5b30d310c..fcb4bc97f95c 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -274,10 +274,17 @@ struct task_group;
#define get_current_state() READ_ONCE(current->__state)
-/* To replace the old hard-coded 16 */
-#define TASK_COMM_LEN_16 16
+/* Also to replace the old hard-coded 16 */
+#define TASK_COMM_LEN_16 16
+#define TASK_COMM_LEN_24 24
+
+
/* Task command name length: */
-#define TASK_COMM_LEN 16
+#if CONFIG_BASE_SMALL
+#define TASK_COMM_LEN TASK_COMM_LEN_16
+#else
+#define TASK_COMM_LEN TASK_COMM_LEN_24
+#endif
extern void scheduler_tick(void);
--
2.17.1
next prev parent reply other threads:[~2021-10-21 3:47 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-21 3:45 [PATCH v5 10/15] tools/lib/perf: use TASK_COMM_LEN_16 instead of hard-coded 16 Yafang Shao
2021-10-21 3:45 ` [PATCH v5 11/15] tools/bpf/bpftool: " Yafang Shao
2021-10-21 22:38 ` Andrii Nakryiko
2021-10-21 3:46 ` [PATCH v5 12/15] tools/perf/test: make perf test adopt to task comm size change Yafang Shao
2021-10-21 3:46 ` [PATCH v5 13/15] tools/testing/selftests/bpf: use TASK_COMM_LEN_16 instead of hard-coded 16 Yafang Shao
2021-10-21 22:44 ` Andrii Nakryiko
2021-10-22 6:36 ` Yafang Shao
2021-10-22 23:41 ` Andrii Nakryiko
2021-10-21 3:46 ` Yafang Shao [this message]
2021-10-21 3:46 ` [PATCH v5 15/15] kernel/kthread: show a warning if kthread's comm is truncated Yafang Shao
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