linux/include
Lai Jiangshan b2aa30f7bb cgroups: don't put struct cgroupfs_root protected by RCU
We don't access struct cgroupfs_root in fast path, so we should not put
struct cgroupfs_root protected by RCU

But the comment in struct cgroup_subsys.root confuse us.

struct cgroup_subsys.root is used in these places:

1 find_css_set(): if (ss->root->subsys_list.next == &ss->sibling)
2 rebind_subsystems(): if (ss->root != &rootnode)
                       rcu_assign_pointer(ss->root, root);
                       rcu_assign_pointer(subsys[i]->root, &rootnode);
3 cgroup_has_css_refs(): if (ss->root != cgrp->root)
4 cgroup_init_subsys(): ss->root = &rootnode;
5 proc_cgroupstats_show(): ss->name, ss->root->subsys_bits,
                           ss->root->number_of_cgroups, !ss->disabled);
6 cgroup_clone(): root = subsys->root;
                  if ((root != subsys->root) ||

All these place we have held cgroup_lock() or we don't dereference to
struct cgroupfs_root.  It's means wo don't need RCU when use struct
cgroup_subsys.root, and we should not put struct cgroupfs_root protected
by RCU.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:02 -08:00
..
acpi
asm-arm
asm-frv frv: introduce asm/swab.h 2009-01-06 18:10:28 -08:00
asm-generic remove linux/hardirq.h from asm-generic/local.h 2009-01-06 15:59:13 -08:00
asm-h8300
asm-m32r m32r: introduce asm/swab.h 2009-01-06 18:10:28 -08:00
asm-m68k m68k: introduce asm/swab.h 2009-01-06 18:10:27 -08:00
asm-mn10300 mn10300: introduce asm/swab.h 2009-01-06 18:10:29 -08:00
crypto
drm
keys
linux cgroups: don't put struct cgroupfs_root protected by RCU 2009-01-08 08:31:02 -08:00
math-emu
media
mtd
net wimax: headers for kernel API and user space interaction 2009-01-07 10:00:16 -08:00
pcmcia
rdma
rxrpc
scsi
sound
trace
video
xen xen: add xenfs to allow usermode <-> Xen interaction 2009-01-08 08:30:59 -08:00
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