mm: bootmem: try harder to free pages in bulk

The loop that frees pages to the page allocator while bootstrapping tries
to free higher-order blocks only when the starting address is aligned to
that block size.  Otherwise it will free all pages on that node
one-by-one.

Change it to free individual pages up to the first aligned block and then
try higher-order frees from there.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 10 insertions, 12 deletions

diff --git a/mm/bootmem.c b/mm/bootmem.c
index 1aea171539ac..668e94df8cf2 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -171,7 +171,6 @@ void __init free_bootmem_late(unsigned long addr, unsigned long size)
 
 static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
 {
-        int aligned;
         struct page *page;
         unsigned long start, end, pages, count = 0;
 
@@ -181,14 +180,8 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
         start = bdata->node_min_pfn;
         end = bdata->node_low_pfn;
 
-        /*
-         * If the start is aligned to the machines wordsize, we might
-         * be able to free pages in bulks of that order.
-         */
-        aligned = !(start & (BITS_PER_LONG - 1));
-
-        bdebug("nid=%td start=%lx end=%lx aligned=%d\n",
-                bdata - bootmem_node_data, start, end, aligned);
+        bdebug("nid=%td start=%lx end=%lx\n",
+                bdata - bootmem_node_data, start, end);
 
         while (start < end) {
                 unsigned long *map, idx, vec;
@@ -196,12 +189,17 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
                 map = bdata->node_bootmem_map;
                 idx = start - bdata->node_min_pfn;
                 vec = ~map[idx / BITS_PER_LONG];
-
-                if (aligned && vec == ~0UL) {
+                /*
+                 * If we have a properly aligned and fully unreserved
+                 * BITS_PER_LONG block of pages in front of us, free
+                 * it in one go.
+                 */
+                if (IS_ALIGNED(start, BITS_PER_LONG) && vec == ~0UL) {
                         int order = ilog2(BITS_PER_LONG);
 
                         __free_pages_bootmem(pfn_to_page(start), order);
                         count += BITS_PER_LONG;
+                        start += BITS_PER_LONG;
                 } else {
                         unsigned long off = 0;
 
@@ -214,8 +212,8 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
                                 vec >>= 1;
                                 off++;
                         }
+                        start = ALIGN(start + 1, BITS_PER_LONG);
                 }
-                start += BITS_PER_LONG;
         }
 
         page = virt_to_page(bdata->node_bootmem_map);