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| author | Eric W. Biederman <ebiederm@xmission.com> | 2019-09-14 07:33:34 -0500 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-09-25 17:42:29 +0200 |
| commit | 3fbd7ee285b2bbc6eebd15a3c8786d9776a402a8 (patch) | |
| tree | a953a7cc7d724fe39e2c1bd2d218d3dd956c180f /include/linux/sched.h | |
| parent | 42fd8baab31f53bed2952485fcf0e92f244c5e55 (diff) | |
| download | lwn-3fbd7ee285b2bbc6eebd15a3c8786d9776a402a8.tar.gz lwn-3fbd7ee285b2bbc6eebd15a3c8786d9776a402a8.zip | |
tasks: Add a count of task RCU users
Add a count of the number of RCU users (currently 1) of the task
struct so that we can later add the scheduler case and get rid of the
very subtle task_rcu_dereference(), and just use rcu_dereference().
As suggested by Oleg have the count overlap rcu_head so that no
additional space in task_struct is required.
Inspired-by: Linus Torvalds <torvalds@linux-foundation.org>
Inspired-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/87woebdplt.fsf_-_@x220.int.ebiederm.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/sched.h')
| -rw-r--r-- | include/linux/sched.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index e2e91960d79f..8e43e54a02c7 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1147,7 +1147,10 @@ struct task_struct { struct tlbflush_unmap_batch tlb_ubc; - struct rcu_head rcu; + union { + refcount_t rcu_users; + struct rcu_head rcu; + }; /* Cache last used pipe for splice(): */ struct pipe_inode_info *splice_pipe; |