Re: [PATCH] mips: sgi-ip27: switch from DISCONTIGMEM to SPARSEMEM

From: Thomas Bogendoerfer <tbogendoerfer@suse.de>
To: Mike Rapoport <rppt@kernel.org>
Cc: Paul Burton <paul.burton@mips.com>,
	linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
	Mike Rapoport <rppt@linux.ibm.com>
Subject: Re: [PATCH] mips: sgi-ip27: switch from DISCONTIGMEM to SPARSEMEM
Date: Wed, 11 Sep 2019 16:09:39 +0200	[thread overview]
Message-ID: <20190911160939.19f776535770d12ff51a2af7@suse.de> (raw)
In-Reply-To: <20190910113243.GA19207@rapoport-lnx>

On Tue, 10 Sep 2019 12:32:44 +0100
Mike Rapoport <rppt@kernel.org> wrote:

> [..]

Patch below works on the same Origin.

Does memblocks_present() deal better with the one reserved page per node
than sparse_memory_present_with_active_regions() ? Or is there a better
explanation ? My debug prints didn't make sense out of it...

Thomas.

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index d50fafd7bf3a..e4b02b5f3487 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -669,6 +669,7 @@ config SGI_IP22
 config SGI_IP27
 	bool "SGI IP27 (Origin200/2000)"
 	select ARCH_HAS_PHYS_TO_DMA
+	select ARCH_SPARSEMEM_ENABLE
 	select FW_ARC
 	select FW_ARC64
 	select BOOT_ELF64
@@ -2633,18 +2634,9 @@ config ARCH_FLATMEM_ENABLE
 	def_bool y
 	depends on !NUMA && !CPU_LOONGSON2
 
-config ARCH_DISCONTIGMEM_ENABLE
-	bool
-	default y if SGI_IP27
-	help
-	  Say Y to support efficient handling of discontiguous physical memory,
-	  for architectures which are either NUMA (Non-Uniform Memory Access)
-	  or have huge holes in the physical address space for other reasons.
-	  See <file:Documentation/vm/numa.rst> for more.
-
 config ARCH_SPARSEMEM_ENABLE
 	bool
-	select SPARSEMEM_STATIC
+	select SPARSEMEM_STATIC if !SGI_IP27
 
 config NUMA
 	bool "NUMA Support"
diff --git a/arch/mips/sgi-ip27/ip27-memory.c b/arch/mips/sgi-ip27/ip27-memory.c
index fb077a947575..370f2ba14a89 100644
--- a/arch/mips/sgi-ip27/ip27-memory.c
+++ b/arch/mips/sgi-ip27/ip27-memory.c
@@ -410,8 +410,6 @@ static void __init node_mem_init(cnodeid_t node)
 
 	memblock_reserve(slot_firstpfn << PAGE_SHIFT,
 			 ((slot_freepfn - slot_firstpfn) << PAGE_SHIFT));
-
-	sparse_memory_present_with_active_regions(node);
 }
 
 /*
@@ -444,6 +442,7 @@ void __init prom_meminit(void)
 		}
 		__node_data[node] = &null_node;
 	}
+	memblocks_present();
 }
 
 void __init prom_free_prom_memory(void)

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