linux/ipc
Davidlohr Bueso e4243b8062 ipc/sem: play nicer with large nsops allocations
Replacing semop()'s kmalloc for kvmalloc was originally proposed by
Manfred on the premise that it can be called for large (than order-1)
sizes.  For example, while Oracle recommends setting SEMOPM to a _minimum_
of 100, some distros[1] encourage the setting to be a factor of the amount
of db tasks (PROCESSES), which can get fishy for large systems (easily
going beyond 1000).

[1] An Example of Semaphore Settings
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/5/html/Tuning_and_Optimizing_Red_Hat_Enterprise_Linux_for_Oracle_9i_and_10g_Databases/sect-Oracle_9i_and_10g_Tuning_Guide-Setting_Semaphores-An_Example_of_Semaphore_Settings.html

So let's just convert this to kvmalloc, just like the rest of the
allocations we do in ipc.  While the fallback vmalloc obviously involves
more overhead, this by far the uncommon path, and it's better for the user
than just erroring out with kmalloc.

Link: http://lkml.kernel.org/r/20170803184136.13855-2-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:51 -07:00
..
Makefile mqueue: move compat syscalls to native ones 2017-07-04 13:13:49 -04:00
compat.c ipc: resolve shadow warnings 2014-10-14 02:18:23 +02:00
ipc_sysctl.c ipc/msg: increase MSGMNI, remove scaling 2014-12-13 12:42:52 -08:00
mq_sysctl.c ipc: convert use of typedef ctl_table to struct ctl_table 2014-06-06 16:08:16 -07:00
mqueue.c mqueue: fix a use-after-free in sys_mq_notify() 2017-07-09 14:37:19 -07:00
msg.c ipc: add missing container_of()s for randstruct 2017-08-02 17:16:12 -07:00
msgutil.c ipc: convert ipc_namespace.count from atomic_t to refcount_t 2017-09-08 18:26:51 -07:00
namespace.c ipc: convert ipc_namespace.count from atomic_t to refcount_t 2017-09-08 18:26:51 -07:00
sem.c ipc/sem: play nicer with large nsops allocations 2017-09-08 18:26:51 -07:00
shm.c ipc: add missing container_of()s for randstruct 2017-08-02 17:16:12 -07:00
syscall.c get rid of union semop in sys_semctl(2) arguments 2013-03-05 15:14:16 -05:00
util.c ipc: convert kern_ipc_perm.refcount from atomic_t to refcount_t 2017-09-08 18:26:51 -07:00
util.h ipc/util.h: update documentation for ipc_getref() and ipc_putref() 2017-07-12 16:26:02 -07:00