• Yinghai Lu's avatar
    mm: sparse: fix usemap allocation above node descriptor section · 99ab7b19
    Yinghai Lu authored
    After commit f5bf18fa ("bootmem/sparsemem: remove limit constraint
    in alloc_bootmem_section"), usemap allocations may easily be placed
    outside the optimal section that holds the node descriptor, even if
    there is space available in that section.  This results in unnecessary
    hotplug dependencies that need to have the node unplugged before the
    section holding the usemap.
    
    The reason is that the bootmem allocator doesn't guarantee a linear
    search starting from the passed allocation goal but may start out at a
    much higher address absent an upper limit.
    
    Fix this by trying the allocation with the limit at the section end,
    then retry without if that fails.  This keeps the fix from f5bf18fa
    of not panicking if the allocation does not fit in the section, but
    still makes sure to try to stay within the section at first.
    Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
    Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
    Cc: <stable@vger.kernel.org>	[3.3.x, 3.4.x]
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    99ab7b19
bootmem.h 5.41 KB