Re: [PATCH 4/10] hot-add-mem x86_64: Enable SPARSEMEM in srat.c

From: Dave Hansen
Date: Fri Aug 04 2006 - 13:40:37 EST


On Fri, 2006-08-04 at 07:14 -0600, Keith Mannthey wrote:
> From: Keith Mannthey <kmannth@xxxxxxxxxx>
>
> Enable x86_64 srat.c to share code between both reserve and sparsemem based add memory
> paths. Both paths need the hot-add area node locality infomration (nodes_add). This
> code refactors the code path to allow this.

I won't respond to all of these, but the set looks pretty darn sane.

> Signed-off-by: Keith Mannthey<kmannth@xxxxxxxxxx>
> ---
> srat.c | 51 +++++++++++++++++++++++++++++----------------------
> 1 files changed, 29 insertions(+), 22 deletions(-)
>
> Files orig/arch/x86_64/mm/.srat.c.swp and current/arch/x86_64/mm/.srat.c.swp differ
> diff -urN orig/arch/x86_64/mm/srat.c current/arch/x86_64/mm/srat.c
> --- orig/arch/x86_64/mm/srat.c 2006-08-04 00:41:17.000000000 -0400
> +++ current/arch/x86_64/mm/srat.c 2006-08-04 01:02:25.000000000 -0400
> @@ -21,12 +21,6 @@
> #include <asm/numa.h>
> #include <asm/e820.h>
>
> -#if (defined(CONFIG_ACPI_HOTPLUG_MEMORY) || \
> - defined(CONFIG_ACPI_HOTPLUG_MEMORY_MODULE)) \
> - && !defined(CONFIG_MEMORY_HOTPLUG)
> -#define RESERVE_HOTADD 1
> -#endif

Thanks goodness this is going away :)

> static struct acpi_table_slit *acpi_slit;
>
> static nodemask_t nodes_parsed __initdata;
> @@ -34,9 +28,6 @@
> static struct bootnode nodes_add[MAX_NUMNODES] __initdata;
> static int found_add_area __initdata;
> int hotadd_percent __initdata = 0;
> -#ifndef RESERVE_HOTADD
> -#define hotadd_percent 0 /* Ignore all settings */
> -#endif
>
> /* Too small nodes confuse the VM badly. Usually they result
> from BIOS bugs. */
> @@ -157,7 +148,7 @@
> pxm, pa->apic_id, node);
> }
>
> -#ifdef RESERVE_HOTADD
> +#ifdef CONFIG_MEMORY_HOTPLUG_RESERVE
> /*
> * Protect against too large hotadd areas that would fill up memory.
> */
> @@ -200,15 +191,37 @@
> return 1;
> }
>
> +static int update_end_of_memory(unsigned long end)
> +{
> + found_add_area = 1;
> + if ((end >> PAGE_SHIFT) > end_pfn)
> + end_pfn = end >> PAGE_SHIFT;
> + return 1;
> +}

I don't have a really strong feeling either way, but you can use
include/linux/pfn.h and PFN_DOWN() here, instead of the explicit >>'s.

> +static inline int save_add_info(void)
> +{
> + return hotadd_percent > 0;
> +}

This name is a wee bit too generic to be in the global namespace.
Perhaps there should be a "memory" in there somewhere.


> -#ifdef RESERVE_HOTADD
> - if (ma->flags.hot_pluggable && reserve_hotadd(node, start, end) < 0) {
> + if (ma->flags.hot_pluggable && !reserve_hotadd(node, start, end) < 0) {
> /* Ignore hotadd region. Undo damage */
> printk(KERN_NOTICE "SRAT: Hotplug region ignored\n");
> *nd = oldnode;
> if ((nd->start | nd->end) == 0)
> node_clear(node, nodes_parsed);
> }
> -#endif
> }

Cool. No more #ifdef.

-- Dave

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