diff options
| author | Mel Gorman <mgorman@suse.de> | 2015-08-07 00:46:13 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-08-07 03:39:40 +0200 |
| commit | 7ace99170789bc53cbb7e9e352d7a3851208fbcf (patch) | |
| tree | 8563a1e739a73bf29bf93154b88ac7ef52209d1c | |
| parent | ipc: modify message queue accounting to not take kernel data structures into ... (diff) | |
| download | linux-7ace99170789bc53cbb7e9e352d7a3851208fbcf.tar.xz linux-7ace99170789bc53cbb7e9e352d7a3851208fbcf.zip | |
mm, meminit: allow early_pfn_to_nid to be used during runtime
early_pfn_to_nid() historically was inherently not SMP safe but only
used during boot which is inherently single threaded or during hotplug
which is protected by a giant mutex.
With deferred memory initialisation there was a thread-safe version
introduced and the early_pfn_to_nid would trigger a BUG_ON if used
unsafely. Memory hotplug hit that check. This patch makes
early_pfn_to_nid introduces a lock to make it safe to use during
hotplug.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Alex Ng <alexng@microsoft.com>
Tested-by: Alex Ng <alexng@microsoft.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Nicolai Stange <nicstange@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/page_alloc.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index ef19f22b2b7d..ea0e6a6e7a11 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -981,21 +981,21 @@ static void __init __free_pages_boot_core(struct page *page, #if defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) || \ defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) -/* Only safe to use early in boot when initialisation is single-threaded */ + static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata; int __meminit early_pfn_to_nid(unsigned long pfn) { + static DEFINE_SPINLOCK(early_pfn_lock); int nid; - /* The system will behave unpredictably otherwise */ - BUG_ON(system_state != SYSTEM_BOOTING); - + spin_lock(&early_pfn_lock); nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache); - if (nid >= 0) - return nid; - /* just returns 0 */ - return 0; + if (nid < 0) + nid = 0; + spin_unlock(&early_pfn_lock); + + return nid; } #endif |