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| author | David Hildenbrand <david@redhat.com> | 2020-10-16 05:07:50 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-10-16 20:11:17 +0200 |
| commit | 4986fac160b3eb1432ca9970d51c55f4f93b1a2e (patch) | |
| tree | edc817dfa2e5e1a80a01da67dd1e2c8a08989e06 | |
| parent | mm/memory_hotplug: inline __offline_pages() into offline_pages() (diff) | |
| download | linux-4986fac160b3eb1432ca9970d51c55f4f93b1a2e.tar.xz linux-4986fac160b3eb1432ca9970d51c55f4f93b1a2e.zip | |
mm/memory_hotplug: enforce section granularity when onlining/offlining
Already two people (including me) tried to offline subsections, because
the function looks like it can deal with it. But we really can only
online/offline full sections that are properly aligned (e.g., we can only
mark full sections online/offline via SECTION_IS_ONLINE).
Add a simple safety net to document the restriction now. Current users
(core and powernv/memtrace) respect these restrictions.
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Charan Teja Reddy <charante@codeaurora.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michel Lespinasse <walken@google.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20200819175957.28465-3-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/memory_hotplug.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index ba201ab4c0e4..03a8825c5620 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -809,6 +809,11 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int ret; struct memory_notify arg; + /* We can only online full sections (e.g., SECTION_IS_ONLINE) */ + if (WARN_ON_ONCE(!nr_pages || + !IS_ALIGNED(pfn | nr_pages, PAGES_PER_SECTION))) + return -EINVAL; + mem_hotplug_begin(); /* associate pfn range with the zone */ @@ -1494,6 +1499,11 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages) struct memory_notify arg; char *reason; + /* We can only offline full sections (e.g., SECTION_IS_ONLINE) */ + if (WARN_ON_ONCE(!nr_pages || + !IS_ALIGNED(start_pfn | nr_pages, PAGES_PER_SECTION))) + return -EINVAL; + mem_hotplug_begin(); /* |