[PATCH] memory hotplug locking: node_size_lock
authorDave Hansen <haveblue@us.ibm.com>
Sun, 30 Oct 2005 01:16:52 +0000 (18:16 -0700)
committerLinus Torvalds <torvalds@g5.osdl.org>
Sun, 30 Oct 2005 04:40:44 +0000 (21:40 -0700)
commit208d54e5513c0c02d85af0990901354c74364d5c
tree83922f1d4a83f19bffcbff299044f421bd7e9c73
parentc6a57e19e464db118dc4ab9cfe9e9748c6d630a0
[PATCH] memory hotplug locking: node_size_lock

pgdat->node_size_lock is basically only neeeded in one place in the normal
code: show_mem(), which is the arch-specific sysrq-m printing function.

Strictly speaking, the architectures not doing memory hotplug do no need this
locking in show_mem().  However, they are all included for completeness.  This
should also make any future consolidation of all of the implementations a
little more straightforward.

This lock is also held in the sparsemem code during a memory removal, as
sections are invalidated.  This is the place there pfn_valid() is made false
for a memory area that's being removed.  The lock is only required when doing
pfn_valid() operations on memory which the user does not already have a
reference on the page, such as in show_mem().

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
arch/alpha/mm/numa.c
arch/i386/mm/pgtable.c
arch/ia64/mm/discontig.c
arch/m32r/mm/init.c
arch/parisc/mm/init.c
arch/ppc64/mm/init.c
include/linux/memory_hotplug.h [new file with mode: 0644]
include/linux/mmzone.h
mm/page_alloc.c