The patch titled
Subject: mm: memmap_init: iterate over memblock regions rather that check each PFN
has been added to the -mm tree. Its filename is
mm-memmap_init-iterate-over-memblock-regions-rather-that-check-each-pfn.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memmap_init-iterate-over-memblock-regions-rather-that-check-each-pfn.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memmap_init-iterate-over-memblock-regions-rather-that-check-each-pfn.patch
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------------------------------------------------------
From: Baoquan He <bhe@xxxxxxxxxx>
Subject: mm: memmap_init: iterate over memblock regions rather that check each PFN
When called during boot the memmap_init_zone() function checks if each PFN
is valid and actually belongs to the node being initialized using
early_pfn_valid() and early_pfn_in_nid().
Each such check may cost up to O(log(n)) where n is the number of memory
banks, so for large amount of memory overall time spent in early_pfn*()
becomes substantial.
Since the information is anyway present in memblock, we can iterate over
memblock memory regions in memmap_init() and only call memmap_init_zone()
for PFN ranges that are know to be valid and in the appropriate node.
Link: http://lkml.kernel.org/r/20200412194859.12663-16-rppt@xxxxxxxxxx
Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: Brian Cain <bcain@xxxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Greentime Hu <green.hu@xxxxxxxxx>
Cc: Greg Ungerer <gerg@xxxxxxxxxxxxxx>
Cc: Guan Xuetao <gxt@xxxxxxxxxx>
Cc: Guo Ren <guoren@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Helge Deller <deller@xxxxxx>
Cc: Hoan Tran <Hoan@xxxxxxxxxxxxxxxxxxxxxx>
Cc: "James E.J. Bottomley" <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Ley Foon Tan <ley.foon.tan@xxxxxxxxx>
Cc: Mark Salter <msalter@xxxxxxxxxx>
Cc: Matt Turner <mattst88@xxxxxxxxx>
Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Michal Simek <monstr@xxxxxxxxx>
Cc: Nick Hu <nickhu@xxxxxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Richard Weinberger <richard@xxxxxx>
Cc: Rich Felker <dalias@xxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Stafford Horne <shorne@xxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
--- a/mm/page_alloc.c~mm-memmap_init-iterate-over-memblock-regions-rather-that-check-each-pfn
+++ a/mm/page_alloc.c
@@ -5995,14 +5995,6 @@ void __meminit memmap_init_zone(unsigned
* function. They do not exist on hotplugged memory.
*/
if (context == MEMMAP_EARLY) {
- if (!early_pfn_valid(pfn)) {
- pfn = next_pfn(pfn);
- continue;
- }
- if (!early_pfn_in_nid(pfn, nid)) {
- pfn++;
- continue;
- }
if (overlap_memmap_init(zone, &pfn))
continue;
if (defer_init(nid, pfn, end_pfn))
@@ -6118,9 +6110,23 @@ static void __meminit zone_init_free_lis
}
void __meminit __weak memmap_init(unsigned long size, int nid,
- unsigned long zone, unsigned long start_pfn)
+ unsigned long zone,
+ unsigned long range_start_pfn)
{
- memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY, NULL);
+ unsigned long start_pfn, end_pfn;
+ unsigned long range_end_pfn = range_start_pfn + size;
+ int i;
+
+ for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
+ start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
+ end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
+
+ if (end_pfn > start_pfn) {
+ size = end_pfn - start_pfn;
+ memmap_init_zone(size, nid, zone, start_pfn,
+ MEMMAP_EARLY, NULL);
+ }
+ }
}
static int zone_batchsize(struct zone *zone)
_
Patches currently in -mm which might be from bhe@xxxxxxxxxx are
mm-memmap_init-iterate-over-memblock-regions-rather-that-check-each-pfn.patch
