]> git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/commit
fork: free vmapped stacks in cache when cpus are offline
authorHoeun Ryu <hoeun.ryu@gmail.com>
Mon, 8 May 2017 22:56:11 +0000 (15:56 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 9 May 2017 00:15:11 +0000 (17:15 -0700)
commit19659c59af52df22d1b85208a2c37b2d46290541
tree8af466708b2cab79ee3c2516eb50c2060ccf2bb7
parent7fe6a42e87ef20edd7faf1b2f4bf18d95922d1e4
fork: free vmapped stacks in cache when cpus are offline

Using virtually mapped stack, kernel stacks are allocated via vmalloc.

In the current implementation, two stacks per cpu can be cached when
tasks are freed and the cached stacks are used again in task
duplications.  But the cached stacks may remain unfreed even when cpu
are offline.  By adding a cpu hotplug callback to free the cached stacks
when a cpu goes offline, the pages of the cached stacks are not wasted.

Link: http://lkml.kernel.org/r/1487076043-17802-1-git-send-email-hoeun.ryu@gmail.com
Signed-off-by: Hoeun Ryu <hoeun.ryu@gmail.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Mateusz Guzik <mguzik@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kernel/fork.c