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Message-ID: <20200331140332.GA2129@MiWiFi-R3L-srv>
Date: Tue, 31 Mar 2020 22:03:32 +0800
From: Baoquan He <bhe@...hat.com>
To: Michal Hocko <mhocko@...nel.org>
Cc: Mike Rapoport <rppt@...ux.ibm.com>,
Hoan Tran <Hoan@...amperecomputing.com>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Andrew Morton <akpm@...ux-foundation.org>,
Vlastimil Babka <vbabka@...e.cz>,
Oscar Salvador <osalvador@...e.de>,
Pavel Tatashin <pavel.tatashin@...rosoft.com>,
Alexander Duyck <alexander.h.duyck@...ux.intel.com>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
"H. Peter Anvin" <hpa@...or.com>,
"David S. Miller" <davem@...emloft.net>,
Heiko Carstens <heiko.carstens@...ibm.com>,
Vasily Gorbik <gor@...ux.ibm.com>,
Christian Borntraeger <borntraeger@...ibm.com>,
"open list:MEMORY MANAGEMENT" <linux-mm@...ck.org>,
linux-arm-kernel@...ts.infradead.org, linux-s390@...r.kernel.org,
sparclinux@...r.kernel.org, x86@...nel.org,
linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
lho@...erecomputing.com, mmorana@...erecomputing.com
Subject: Re: [PATCH v3 0/5] mm: Enable CONFIG_NODES_SPAN_OTHER_NODES by
default for NUMA
Hi Michal,
On 03/31/20 at 10:55am, Michal Hocko wrote:
> On Tue 31-03-20 11:14:23, Mike Rapoport wrote:
> > Maybe I mis-read the code, but I don't see how this could happen. In the
> > HAVE_MEMBLOCK_NODE_MAP=y case, free_area_init_node() calls
> > calculate_node_totalpages() that ensures that node->node_zones are entirely
> > within the node because this is checked in zone_spanned_pages_in_node().
>
> zone_spanned_pages_in_node does chech the zone boundaries are within the
> node boundaries. But that doesn't really tell anything about other
> potential zones interleaving with the physical memory range.
> zone->spanned_pages simply gives the physical range for the zone
> including holes. Interleaving nodes are essentially a hole
> (__absent_pages_in_range is going to skip those).
>
> That means that when free_area_init_core simply goes over the whole
> physical zone range including holes and that is why we need to check
> both for physical and logical holes (aka other nodes).
>
> The life would be so much easier if the whole thing would simply iterate
> over memblocks...
The memblock iterating sounds a great idea. I tried with putting the
memblock iterating in the upper layer, memmap_init(), which is used for
boot mem only anyway. Do you think it's doable and OK? It yes, I can
work out a formal patch to make this simpler as you said. The draft code
is as below. Like this it uses the existing code and involves little change.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 138a56c0f48f..558d421f294b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6007,14 +6007,6 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
* 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))
@@ -6130,9 +6122,17 @@ static void __meminit zone_init_free_lists(struct zone *zone)
}
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)
+ memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY, NULL);
+ }
}
static int zone_batchsize(struct zone *zone)
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