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Commit 54608c3f authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

mm: meminit: minimise number of pfn->page lookups during initialisation 



Deferred struct page initialisation is using pfn_to_page() on every PFN
unnecessarily.  This patch minimises the number of lookups and scheduler
checks.

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 7e18adb4

mm/page_alloc.c

+24 −5
Original line number Diff line number Diff line
@@ -1091,6 +1091,7 @@ void __defermem_init deferred_init_memmap(int nid) 


	for_each_mem_pfn_range(i, nid, &walk_start, &walk_end, NULL) {

		unsigned long pfn, end_pfn;

		struct page *page = NULL;



		end_pfn = min(walk_end, zone_end_pfn(zone));

		pfn = first_init_pfn;
@@ -1100,13 +1101,32 @@ void __defermem_init deferred_init_memmap(int nid) 
			pfn = zone->zone_start_pfn;



		for (; pfn < end_pfn; pfn++) {

			struct page *page;

			if (!pfn_valid_within(pfn))

				continue;



			if (!pfn_valid(pfn))

			/*

			 * Ensure pfn_valid is checked every

			 * MAX_ORDER_NR_PAGES for memory holes

			 */

			if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0) {

				if (!pfn_valid(pfn)) {

					page = NULL;

					continue;

				}

			}



			if (!meminit_pfn_in_nid(pfn, nid, &nid_init_state))

			if (!meminit_pfn_in_nid(pfn, nid, &nid_init_state)) {

				page = NULL;

				continue;

			}



			/* Minimise pfn page lookups and scheduler checks */

			if (page && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) {

				page++;

			} else {

				page = pfn_to_page(pfn);

				cond_resched();

			}



			if (page->flags) {

				VM_BUG_ON(page_zone(page) != zone);
@@ -1116,7 +1136,6 @@ void __defermem_init deferred_init_memmap(int nid) 
			__init_single_page(page, pfn, zid, nid);

			__free_pages_boot_core(page, pfn, 0);

			nr_pages++;

			cond_resched();

		}

		first_init_pfn = max(end_pfn, first_init_pfn);

	}