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Date:   Tue, 15 Dec 2020 17:01:33 +0800
From:   Baoquan He <bhe@redhat.com>
To:     Mike Rapoport <rppt@kernel.org>
Cc:     David Hildenbrand <david@redhat.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, gopakumarr@vmware.com,
        akpm@linux-foundation.org, natechancellor@gmail.com,
        ndesaulniers@google.com, clang-built-linux@googlegroups.com,
        rostedt@goodmis.org, manir@vmware.com, lauyiuch@vmware.com,
        pjonasson@vmware.com, rajaramv@vmware.com
Subject: Re: [PATCH 2/2] mm: rename memmap_init() and memmap_init_zone()
Message-ID: <20201215090133.GB8928@MiWiFi-R3L-srv>
References: <20201213150942.20990-1-bhe@redhat.com>
 <20201213150942.20990-3-bhe@redhat.com>
 <c53c5290-b5c1-87bb-d562-348d4c8bd7eb@redhat.com>
 <20201214110448.GB198219@kernel.org>
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On 12/14/20 at 01:04pm, Mike Rapoport wrote:
> On Mon, Dec 14, 2020 at 11:00:07AM +0100, David Hildenbrand wrote:
> > On 13.12.20 16:09, Baoquan He wrote:
> > > The current memmap_init_zone() only handles memory region inside one zone.
> > > Actually memmap_init() does the memmap init of one zone. So rename both of
> > > them accordingly.
> > > 
> > > And also rename the function parameter 'range_start_pfn' and local variable
> > > 'range_end_pfn' to zone_start_pfn/zone_end_pfn.
> > > 
> > > Signed-off-by: Baoquan He <bhe@redhat.com>
> > > ---
......  

> > >  	set_zone_contiguous(zone);
> > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > > index 315c22974f0d..fac599deba56 100644
> > > --- a/mm/page_alloc.c
> > > +++ b/mm/page_alloc.c
> > > @@ -6050,7 +6050,7 @@ overlap_memmap_init(unsigned long zone, unsigned long *pfn)
> > >   * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related
> > >   * zone stats (e.g., nr_isolate_pageblock) are touched.
> > >   */
> > > -void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
> > > +void __meminit memmap_init_range(unsigned long size, int nid, unsigned long zone,
> > >  		unsigned long start_pfn, unsigned long zone_end_pfn,
> > >  		enum meminit_context context,
> > >  		struct vmem_altmap *altmap, int migratetype)
> > > @@ -6187,21 +6187,21 @@ static void __meminit zone_init_free_lists(struct zone *zone)
> > >  	}
> > >  }
> > >  
> > > -void __meminit __weak memmap_init(unsigned long size, int nid,
> > > +void __meminit __weak memmap_init_zone(unsigned long size, int nid,
> > >  				  unsigned long zone,
> > > -				  unsigned long range_start_pfn)
> > > +				  unsigned long zone_start_pfn)
> > 
> > Why are we not simply passing "struct zone" like
> > 
> > void __meminit __weak  memmap_init_zone(struct zone *zone)
> > 
> > from which we can derive
> > - nid
> > - zone idx
> > - zone_start_pfn
> > - spanned_pages / zone_end_pfn
> > 
> > At least when called from free_area_init_core() this should work just
> > fine I think.
>  
> There is also a custom memmap init in ia64 which at least should be
> tested ;-)

Right. Tried in arch/ia64/mm/init.c, the change is as below. Looks
simple, compiling passed on ia64 should be OK.


diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index af678197ac2d..4fa49a762d58 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -541,12 +541,14 @@ virtual_memmap_init(u64 start, u64 end, void *arg)
 	return 0;
 }
 
-void __meminit
-memmap_init_zone (unsigned long size, int nid, unsigned long zone,
-	     unsigned long start_pfn)
+void __meminit memmap_init_zone (struct zone *zone)
 {
+	unsigned long size = zone->spanned_size;
+	int nid = zone_to_nid(zone), zone_id = zone_idx(zone);
+	unsigned long start_pfn = zone->zone_start_pfn;
+
 	if (!vmem_map) {
-		memmap_init_range(size, nid, zone, start_pfn, start_pfn + size,
+		memmap_init_range(size, nid, zone_id, start_pfn, start_pfn + size,
 				 MEMINIT_EARLY, NULL, MIGRATE_MOVABLE);
 	} else {
 		struct page *start;
@@ -556,7 +558,7 @@ memmap_init_zone (unsigned long size, int nid, unsigned long zone,
 		args.start = start;
 		args.end = start + size;
 		args.nid = nid;
-		args.zone = zone;
+		args.zone = zone_id;
 
 		efi_memmap_walk(virtual_memmap_init, &args);
 	}
> 
> More broadly, while Baoquan's fix looks Ok to me, I think we can
> calculate node->first_deferred_pfn earlier in, say,
> free_area_init_node() rather than do defer_init() check for each pfn.

Remember I ever tried to move the defer init up one level into memmap_init()
when making draft patch in the first place. I finally ended up with this
because there's overlap_memmap_init().

>  
> > >  {
> > >  	unsigned long start_pfn, end_pfn;
> > > -	unsigned long range_end_pfn = range_start_pfn + size;
> > > +	unsigned long zone_end_pfn = zone_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);
> > > +		start_pfn = clamp(start_pfn, zone_start_pfn, zone_end_pfn);
> > > +		end_pfn = clamp(end_pfn, zone_start_pfn, zone_end_pfn);
> > >  
> > >  		if (end_pfn > start_pfn) {
> > >  			size = end_pfn - start_pfn;
> > > -			memmap_init_zone(size, nid, zone, start_pfn, range_end_pfn,
> > > +			memmap_init_range(size, nid, zone, start_pfn, zone_end_pfn,
> > >  					 MEMINIT_EARLY, NULL, MIGRATE_MOVABLE);
> > >  		}
> > >  	}
> > > @@ -6903,7 +6903,7 @@ static void __init free_area_init_core(struct pglist_data *pgdat)
> > >  		set_pageblock_order();
> > >  		setup_usemap(pgdat, zone, zone_start_pfn, size);
> > >  		init_currently_empty_zone(zone, zone_start_pfn, size);
> > > -		memmap_init(size, nid, j, zone_start_pfn);
> > > +		memmap_init_zone(size, nid, j, zone_start_pfn);
> > >  	}
> > >  }
> > >  
> > > 
> > 
> > 
> > -- 
> > Thanks,
> > 
> > David / dhildenb
> > 
> 
> -- 
> Sincerely yours,
> Mike.
>