[RFC PATCH 2/4] x86/setup: parse acpi to get hotplug info before init_mem_mapping()

[Pingfan Liu]

At present, memblock bottom-up allocation can help us against stamping over
movable node in very high probability. But if the hotplug info has already
been parsed, the memblock allocator can step around the movable node by
itself. This patch pushes the parsing step forward, just ahead of where,
the memblock allocator can work. Later in this series, the bottom-up
allocation style can be removed on x86_64.

Signed-off-by: Pingfan Liu <kernelfans@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
 arch/x86/kernel/setup.c | 15 +++++++++++++++
 include/linux/acpi.h    |  1 +
 2 files changed, 16 insertions(+)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index acbcd62..df4132c 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -805,6 +805,20 @@ dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
 	return 0;
 }
 
+/* only need the effect of acpi_numa_memory_affinity_init()
+ * ->memblock_mark_hotplug()
+ */
+static int early_detect_acpi_memhotplug(void)
+{
+#ifdef CONFIG_ACPI_NUMA
+	acpi_table_upgrade(__va(get_ramdisk_image()), get_ramdisk_size());
+	acpi_table_init();
+	acpi_numa_init();
+	acpi_tb_terminate();
+#endif
+	return 0;
+}
+
 /*
  * Determine if we were loaded by an EFI loader.  If so, then we have also been
  * passed the efi memmap, systab, etc., so we should use these data structures
@@ -1131,6 +1145,7 @@ void __init setup_arch(char **cmdline_p)
 	trim_platform_memory_ranges();
 	trim_low_memory_range();
 
+	early_detect_acpi_memhotplug();
 	init_mem_mapping();
 
 	idt_setup_early_pf();
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 44dcbba..1b69044 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -235,6 +235,7 @@ int acpi_mps_check (void);
 int acpi_numa_init (void);
 
 int acpi_table_init (void);
+void acpi_tb_terminate(void);
 int acpi_table_parse(char *id, acpi_tbl_table_handler handler);
 int __init acpi_table_parse_entries(char *id, unsigned long table_size,
 			      int entry_id,
-- 
2.7.4