Commit 8a942fde authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

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



__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: default avatarMel Gorman <mgorman@suse.de>
Tested-by: default avatarNate Zimmer <nzimmer@sgi.com>
Tested-by: default avatarWaiman Long <waiman.long@hp.com>
Tested-by: default avatarDaniel J Blueman <daniel@numascale.com>
Acked-by: default avatarPekka 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d70ddd7a

arch/ia64/mm/numa.c

+7 −12
Original line number Diff line number Diff line
@@ -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;

		}

	}

include/linux/mm.h

+4 −2
Original line number Diff line number Diff line
@@ -1726,7 +1726,8 @@ extern void sparse_memory_present_with_active_regions(int nid); 


#if !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) && \

    !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID)

static inline int __early_pfn_to_nid(unsigned long pfn)

static inline int __early_pfn_to_nid(unsigned long pfn,

					struct mminit_pfnnid_cache *state)

{

	return 0;

}
@@ -1734,7 +1735,8 @@ static inline int __early_pfn_to_nid(unsigned long pfn) 
/* please see mm/page_alloc.c */

extern int __meminit early_pfn_to_nid(unsigned long pfn);

/* there is a per-arch backend function. */

extern int __meminit __early_pfn_to_nid(unsigned long pfn);

extern int __meminit __early_pfn_to_nid(unsigned long pfn,

					struct mminit_pfnnid_cache *state);

#endif



extern void set_dma_reserve(unsigned long new_dma_reserve);

include/linux/mmzone.h

+15 −1
Original line number Diff line number Diff line
@@ -1216,10 +1216,24 @@ void sparse_init(void); 
#define sparse_index_init(_sec, _nid)  do {} while (0)

#endif /* CONFIG_SPARSEMEM */



/*

 * During memory init memblocks map pfns to nids. The search is expensive and

 * this caches recent lookups. The implementation of __early_pfn_to_nid

 * may treat start/end as pfns or sections.

 */

struct mminit_pfnnid_cache {

	unsigned long last_start;

	unsigned long last_end;

	int last_nid;

};



#ifdef CONFIG_NODES_SPAN_OTHER_NODES

bool early_pfn_in_nid(unsigned long pfn, int nid);

bool meminit_pfn_in_nid(unsigned long pfn, int node,

			struct mminit_pfnnid_cache *state);

#else

#define early_pfn_in_nid(pfn, nid)		(1)

#define meminit_pfn_in_nid(pfn, nid, state)	(1)

#endif



#ifndef early_pfn_valid

mm/page_alloc.c

+25 −15
Original line number Diff line number Diff line
@@ -4551,39 +4551,41 @@ int __meminit init_currently_empty_zone(struct zone *zone, 


#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP

#ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID



/*

 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.

 */

int __meminit __early_pfn_to_nid(unsigned long pfn)

int __meminit __early_pfn_to_nid(unsigned long pfn,

					struct mminit_pfnnid_cache *state)

{

	unsigned long start_pfn, end_pfn;

	int nid;

	/*

	 * NOTE: The following SMP-unsafe globals are only used early in boot

	 * when the kernel is running single-threaded.

	 */

	static unsigned long __meminitdata last_start_pfn, last_end_pfn;

	static int __meminitdata last_nid;



	if (last_start_pfn <= pfn && pfn < last_end_pfn)

		return last_nid;

	if (state->last_start <= pfn && pfn < state->last_end)

		return state->last_nid;



	nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);

	if (nid != -1) {

		last_start_pfn = start_pfn;

		last_end_pfn = end_pfn;

		last_nid = nid;

		state->last_start = start_pfn;

		state->last_end = end_pfn;

		state->last_nid = nid;

	}



	return nid;

}

#endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */



static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;



/* Only safe to use early in boot when initialisation is single-threaded */

int __meminit early_pfn_to_nid(unsigned long pfn)

{

	int nid;



	nid = __early_pfn_to_nid(pfn);

	/* The system will behave unpredictably otherwise */

	BUG_ON(system_state != SYSTEM_BOOTING);



	nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);

	if (nid >= 0)

		return nid;

	/* just returns 0 */
@@ -4591,15 +4593,23 @@ int __meminit early_pfn_to_nid(unsigned long pfn) 
}



#ifdef CONFIG_NODES_SPAN_OTHER_NODES

bool __meminit early_pfn_in_nid(unsigned long pfn, int node)

bool __meminit meminit_pfn_in_nid(unsigned long pfn, int node,

					struct mminit_pfnnid_cache *state)

{

	int nid;



	nid = __early_pfn_to_nid(pfn);

	nid = __early_pfn_to_nid(pfn, state);

	if (nid >= 0 && nid != node)

		return false;

	return true;

}



/* Only safe to use early in boot when initialisation is single-threaded */

bool __meminit early_pfn_in_nid(unsigned long pfn, int node)

{

	return meminit_pfn_in_nid(pfn, node, &early_pfnnid_cache);

}



#endif



/**

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