linux/fs/proc
Chris Metcalf f51c0eaee3 procfs: treat parked tasks as sleeping for task state
Allowing watchdog threads to be parked means that we now have the
opportunity of actually seeing persistent parked threads in the output
of /proc/<pid>/stat and /proc/<pid>/status.  The existing code reported
such threads as "Running", which is kind-of true if you think of the
case where we park them as part of taking cpus offline.  But if we allow
parking them indefinitely, "Running" is pretty misleading, so we report
them as "Sleeping" instead.

We could simply report them with a new string, "Parked", but it feels
like it's a bit risky for userspace to see unexpected new values; the
output is already documented in Documentation/filesystems/proc.txt, and
it seems like a mistake to change that lightly.

The scheduler does report parked tasks with a "P" in debugging output
from sched_show_task() or dump_cpu_task(), but that's a different API.
Similarly, the trace_ctxwake_* routines report a "P" for parked tasks,
but again, different API.

This change seemed slightly cleaner than updating the task_state_array
to have additional rows.  TASK_DEAD should be subsumed by the exit_state
bits; TASK_WAKEKILL is just a modifier; and TASK_WAKING can very
reasonably be reported as "Running" (as it is now).  Only TASK_PARKED
shows up with unreasonable output here.

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:40 -07:00
..
array.c procfs: treat parked tasks as sleeping for task state 2015-06-24 17:49:40 -07:00
base.c don't pass nameidata to ->follow_link() 2015-05-10 22:20:15 -04:00
cmdline.c
consoles.c
cpuinfo.c
devices.c
fd.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
fd.h
generic.c VFS: normal filesystems (and lustre): d_inode() annotations 2015-04-15 15:06:57 -04:00
inode.c switch ->put_link() from dentry to inode 2015-05-11 08:13:12 -04:00
internal.h procfs: fix race between symlink removals and traversals 2015-02-22 11:43:12 -05:00
interrupts.c
Kconfig
kcore.c
kmsg.c
loadavg.c
Makefile
meminfo.c fs/proc/meminfo.c: include cma info in proc/meminfo 2014-12-18 19:08:10 -08:00
namespaces.c don't pass nameidata to ->follow_link() 2015-05-10 22:20:15 -04:00
nommu.c
page.c mm:add KPF_ZERO_PAGE flag for /proc/kpageflags 2015-02-11 17:06:00 -08:00
proc_net.c VFS: normal filesystems (and lustre): d_inode() annotations 2015-04-15 15:06:57 -04:00
proc_sysctl.c VFS: normal filesystems (and lustre): d_inode() annotations 2015-04-15 15:06:57 -04:00
proc_tty.c
root.c VFS: normal filesystems (and lustre): d_inode() annotations 2015-04-15 15:06:57 -04:00
self.c don't pass nameidata to ->follow_link() 2015-05-10 22:20:15 -04:00
softirqs.c
stat.c genirq: Prevent proc race against freeing of irq descriptors 2014-12-13 13:33:07 +01:00
task_mmu.c pagemap: do not leak physical addresses to non-privileged userspace 2015-03-17 09:31:30 -07:00
task_nommu.c
thread_self.c don't pass nameidata to ->follow_link() 2015-05-10 22:20:15 -04:00
uptime.c
version.c
vmcore.c vmcore: fix PT_NOTE n_namesz, n_descsz overflow issue 2015-02-17 14:34:52 -08:00