mm: meminit: free pages in large chunks where possible

Parallel struct page frees pages one at a time. Try free pages as single
large pages where possible.

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>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0f770cc13450a4fa56425fb395b14ad7a54712d1..e3f00f622f28e400a7a578314e1eef603b86388e 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1062,6 +1062,25 @@ void __defer_init __free_pages_bootmem(struct page *page, unsigned long pfn,
 }
 
 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+static void __defermem_init deferred_free_range(struct page *page,
+                                       unsigned long pfn, int nr_pages)
+{
+       int i;
+
+       if (!page)
+               return;
+
+       /* Free a large naturally-aligned chunk if possible */
+       if (nr_pages == MAX_ORDER_NR_PAGES &&
+           (pfn & (MAX_ORDER_NR_PAGES-1)) == 0) {
+               __free_pages_boot_core(page, pfn, MAX_ORDER-1);
+               return;
+       }
+
+       for (i = 0; i < nr_pages; i++, page++, pfn++)
+               __free_pages_boot_core(page, pfn, 0);
+}
+
 /* Initialise remaining memory on a node */
 void __defermem_init deferred_init_memmap(int nid)
 {
@@ -1092,6 +1111,9 @@ 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;
+               struct page *free_base_page = NULL;
+               unsigned long free_base_pfn = 0;
+               int nr_to_free = 0;
 
                end_pfn = min(walk_end, zone_end_pfn(zone));
                pfn = first_init_pfn;
@@ -1102,7 +1124,7 @@ void __defermem_init deferred_init_memmap(int nid)
 
                for (; pfn < end_pfn; pfn++) {
                        if (!pfn_valid_within(pfn))
-                               continue;
+                               goto free_range;
 
                        /*
                         * Ensure pfn_valid is checked every
@@ -1111,32 +1133,53 @@ void __defermem_init deferred_init_memmap(int nid)
                        if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0) {
                                if (!pfn_valid(pfn)) {
                                        page = NULL;
-                                       continue;
+                                       goto free_range;
                                }
                        }
 
                        if (!meminit_pfn_in_nid(pfn, nid, &nid_init_state)) {
                                page = NULL;
-                               continue;
+                               goto free_range;
                        }
 
                        /* Minimise pfn page lookups and scheduler checks */
                        if (page && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) {
                                page++;
                        } else {
+                               nr_pages += nr_to_free;
+                               deferred_free_range(free_base_page,
+                                               free_base_pfn, nr_to_free);
+                               free_base_page = NULL;
+                               free_base_pfn = nr_to_free = 0;
+
                                page = pfn_to_page(pfn);
                                cond_resched();
                        }
 
                        if (page->flags) {
                                VM_BUG_ON(page_zone(page) != zone);
-                               continue;
+                               goto free_range;
                        }
 
                        __init_single_page(page, pfn, zid, nid);
-                       __free_pages_boot_core(page, pfn, 0);
-                       nr_pages++;
+                       if (!free_base_page) {
+                               free_base_page = page;
+                               free_base_pfn = pfn;
+                               nr_to_free = 0;
+                       }
+                       nr_to_free++;
+
+                       /* Where possible, batch up pages for a single free */
+                       continue;
+free_range:
+                       /* Free the current block of pages to allocator */
+                       nr_pages += nr_to_free;
+                       deferred_free_range(free_base_page, free_base_pfn,
+                                                               nr_to_free);
+                       free_base_page = NULL;
+                       free_base_pfn = nr_to_free = 0;
                }
+
                first_init_pfn = max(end_pfn, first_init_pfn);
        }