lkml.org 
[lkml]   [2019]   [Aug]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v1 2/4] mm/memory_hotplug: Handle unaligned start and nr_pages in online_pages_blocks()
Date
Take care of nr_pages not being a power of two and start not being
properly aligned. Essentially, what walk_system_ram_range() could provide
to us. get_order() will round-up in case it's not a power of two.

This should only apply to memory blocks that contain strange memory
resources (especially with holes), not to ordinary DIMMs.

Fixes: a9cd410a3d29 ("mm/page_alloc.c: memory hotplug: free pages as higher order")
Cc: Arun KS <arunks@codeaurora.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
mm/memory_hotplug.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 3706a137d880..2abd938c8c45 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -640,6 +640,10 @@ static int online_pages_blocks(unsigned long start, unsigned long nr_pages)
while (start < end) {
order = min(MAX_ORDER - 1,
get_order(PFN_PHYS(end) - PFN_PHYS(start)));
+ /* make sure the PFN is aligned and we don't exceed the range */
+ while (!IS_ALIGNED(start, 1ul << order) ||
+ (1ul << order) > end - start)
+ order--;
(*online_page_callback)(pfn_to_page(start), order);

onlined_pages += (1UL << order);
--
2.21.0
\
 
 \ /
  Last update: 2019-08-09 15:00    [W:0.108 / U:0.816 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site