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

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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: 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 14:57:09 -07:00 committed by Linus Torvalds
parent 7e18adb4f8
commit 54608c3f3a
1 changed files with 24 additions and 5 deletions
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29
mm/page_alloc.c
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@ -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(pfn))
if (!pfn_valid_within(pfn))
continue;
if (!meminit_pfn_in_nid(pfn, nid, &nid_init_state))
/*
* 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)) {
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);
}