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mm: meminit: make __early_pfn_to_nid SMP-safe and introduce meminit_pfn_in_nid

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__early_pfn_to_nid() use static variables to cache recent lookups as
memblock lookups are very expensive but it assumes that memory
initialisation is single-threaded.  Parallel initialisation of struct
pages will break that assumption so this patch makes __early_pfn_to_nid()
SMP-safe by requiring the caller to cache recent search information.
early_pfn_to_nid() keeps the same interface but is only safe to use early
in boot due to the use of a global static variable.  meminit_pfn_in_nid()
is an SMP-safe version that callers must maintain their own state for.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mel Gorman
2015-06-30 14:56:55 -07:00
committed by Linus Torvalds
parent d70ddd7a5d
commit 8a942fdea5
4 changed files with 51 additions and 30 deletions
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19
arch/ia64/mm/numa.c
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@@ -58,27 +58,22 @@ paddr_to_nid(unsigned long paddr)
* SPARSEMEM to allocate the SPARSEMEM sectionmap on the NUMA node where
* the section resides.
*/
int __meminit __early_pfn_to_nid(unsigned long pfn)
int __meminit __early_pfn_to_nid(unsigned long pfn,
struct mminit_pfnnid_cache *state)
{
int i, section = pfn >> PFN_SECTION_SHIFT, ssec, esec;
/*
* NOTE: The following SMP-unsafe globals are only used early in boot
* when the kernel is running single-threaded.
*/
static int __meminitdata last_ssec, last_esec;
static int __meminitdata last_nid;
if (section >= last_ssec && section < last_esec)
return last_nid;
if (section >= state->last_start && section < state->last_end)
return state->last_nid;
for (i = 0; i < num_node_memblks; i++) {
ssec = node_memblk[i].start_paddr >> PA_SECTION_SHIFT;
esec = (node_memblk[i].start_paddr + node_memblk[i].size +
((1L << PA_SECTION_SHIFT) - 1)) >> PA_SECTION_SHIFT;
if (section >= ssec && section < esec) {
last_ssec = ssec;
last_esec = esec;
last_nid = node_memblk[i].nid;
state->last_start = ssec;
state->last_end = esec;
state->last_nid = node_memblk[i].nid;
return node_memblk[i].nid;
}
}