On Wed, Jul 11, 2012 at 04:40:00PM -0700, [email protected] wrote: > > The patch below does not apply to the 3.4-stable tree. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to <[email protected]>. > > thanks, > > greg k-h
--- From: Johannes Weiner <[email protected]> Subject: [patch] mm: bootmem: fix sparse usemap allocation above node descriptor section commit 99ab7b19440a72ebdf225f99b20f8ef40decee86 upstream. After commit f5bf18fa22f8 ("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 again, but not if this is impossible due to the size of the allocation. This keeps the fix from f5bf18fa22f8 of not panicking if the allocation does not fit in the section, but still makes sure to try to stay within the section if possible. Signed-off-by: Johannes Weiner <[email protected]> --- mm/bootmem.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/bootmem.c b/mm/bootmem.c index 0131170..53cf62b 100644 --- a/mm/bootmem.c +++ b/mm/bootmem.c @@ -766,13 +766,17 @@ void * __init alloc_bootmem_section(unsigned long size, unsigned long section_nr) { bootmem_data_t *bdata; - unsigned long pfn, goal; + unsigned long pfn, goal, limit; pfn = section_nr_to_pfn(section_nr); goal = pfn << PAGE_SHIFT; + limit = section_nr_to_pfn(section_nr + 1) << PAGE_SHIFT; bdata = &bootmem_node_data[early_pfn_to_nid(pfn)]; - return alloc_bootmem_core(bdata, size, SMP_CACHE_BYTES, goal, 0); + if (goal + size > limit) + limit = 0; + + return alloc_bootmem_core(bdata, size, SMP_CACHE_BYTES, goal, limit); } #endif -- 1.7.11.2 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
