]> git.proxmox.com Git - mirror_ubuntu-hirsute-kernel.git/commit
shm: allow exit_shm in parallel if only marking orphans
authorJack Miller <millerjo@us.ibm.com>
Fri, 8 Aug 2014 21:23:21 +0000 (14:23 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 8 Aug 2014 22:57:26 +0000 (15:57 -0700)
commit83293c0f5a6130bf7d60b7b406f4a4de0cadd3d8
tree9800879dfd131c263d57276c29494b06deac7f70
parentab602f799159393143d567e5c04b936fec79d6bd
shm: allow exit_shm in parallel if only marking orphans

If shm_rmid_force (the default state) is not set then the shmids are only
marked as orphaned and does not require any add, delete, or locking of the
tree structure.

Seperate the sysctl on and off case, and only obtain the read lock.  The
newly added list head can be deleted under the read lock because we are
only called with current and will only change the semids allocated by this
task and not manipulate the list.

This commit assumes that up_read includes a sufficient memory barrier for
the writes to be seen my others that later obtain a write lock.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Jack Miller <millerjo@us.ibm.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipc/shm.c