• Dave Hansen's avatar
    [PATCH] memory hotplug locking: node_size_lock · 208d54e5
    Dave Hansen authored
    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: default avatarDave Hansen <haveblue@us.ibm.com>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    208d54e5
page_alloc.c 63.6 KB