Use atomic_t for ucounts reference counting

Browse source

The current implementation of the ucounts reference counter requires the
use of spin_lock. We're going to use get_ucounts() in more performance
critical areas like a handling of RLIMIT_SIGPENDING.

Now we need to use spin_lock only if we want to change the hashtable.

v10:
* Always try to put ucounts in case we cannot increase ucounts->count.
  This will allow to cover the case when all consumers will return
  ucounts at once.

v9:
* Use a negative value to check that the ucounts->count is close to
  overflow.

Signed-off-by: Alexey Gladkov <legion@kernel.org>
Link: https://lkml.kernel.org/r/94d1dbecab060a6b116b0a2d1accd8ca1bbb4f5f.1619094428.git.legion@kernel.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

...

This commit is contained in:

Alexey Gladkov 2021-04-22 14:27:10 +02:00 • committed by Eric W. Biederman

parent 905ae01c4a

commit b6c3365289

2 changed files with 21 additions and 36 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

4

include/linux/user_namespace.h

View file

53

kernel/ucount.c

View file