[PATCH 5/7] At boot, determine what zone memory will hot-add to

Mel Gorman
2006-02-17T14:17:32Z

Once ZONE_EASYRCLM is added, the x86 by default adds to ZONE_EASYRCLM and
ppc64 by default uses ZONE_DMA. This patch changes the behavior slightly on
x86 and ppc64.

o By default, ZONE_DMA is used on ppc64 and ZONE_HIGHMEM is used on x86
o If kernelcore is specified at boot time, x86 and ppc64 hotadd to ZONE_EASYRCLM
o If kernelcore and noeasyrclm is used, ppc64 will use ZONE_DMA and x86 will
use ZONE_HIGHMEM

This is a list of scenarios and what happens with different options on an
x86 with 1.5GiB of physical RAM. ./activate is a script that tries to online
all inactive physical memory.

Boot with no special parameters
- ./activate does nothing
- All high memory in HIGHMEM

Boot with mem=512MB
- Machine boots with 512MB active RAM
- ./activate adds memory to ZONE_HIGHMEM
- No memory in ZONE_EASYRCLM

Boot with kernelcore=512MB
- Machine boots with 1.5GiB RAM
- ./activate does nothing
- No memory in HIGHMEM
- Some of what would be NORMAL and all of HIGHMEM is in EASYRCLM

Boot with kernelcore=512MB mem=512MB
- Machine boots with 512MB RAM
- ./activate adds memory to ZONE_EASYRCLM
- No memory in HIGHMEM

Boot with kernelcore=512MB mem=512MB noeasyrclm
- Machine boots with 512MB RAM
- ./activate adds memory to ZONE_EASYRCLM
- No memory in HIGHMEM
- With noeasyrclm, this is identical to booting with just mem=512MB

Boot with kernelcore=1024MB mem=1024MB
- Machine boots with 1024MB RAM
- Some memory already in ZONE_HIGHMEM
- ./activate adds memory to ZONE_EASYRCLM

Boot with kernelcore=1024MB mem=1024MB noeasyrclm
- Machine boots with 1024MB RAM
- Some memory already in ZONE_EASYRCLM
- ./activate adds memory to ZONE_HIGHMEM

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
diff -rup -X /usr/src/patchset-0.5/bin//dontdiff linux-2.6.16-rc3-mm1-104_ppc64coremem/arch/i386/kernel/setup.c linux-2.6.16-rc3-mm1-106_zonechoose/arch/i386/kernel/setup.c
--- linux-2.6.16-rc3-mm1-104_ppc64coremem/arch/i386/kernel/setup.c 2006-02-17 09:42:45.000000000 +0000
+++ linux-2.6.16-rc3-mm1-106_zonechoose/arch/i386/kernel/setup.c 2006-02-17 09:44:16.000000000 +0000
@@ -115,6 +115,8 @@ static unsigned int highmem_pages = -1;
/* user-defined easy-reclaim-size */
static unsigned int core_mem_pages = -1;
static unsigned int easyrclm_pages = 0;
+static int hotadd_zone_offset = -1;
+
/*
* Setup options
*/
@@ -923,6 +925,18 @@ static void __init parse_cmdline_early (
*/
else if (!memcmp(from, "kernelcore=",11)) {
core_mem_pages = memparse(from+11, &from) >> PAGE_SHIFT;
+
+ if (hotadd_zone_offset == -1)
+ hotadd_zone_offset = ZONE_EASYRCLM;
+ }
+
+ /*
+ * Once kernelcore= is specified, the default zone to add to
+ * is ZONE_EASYRCLM. This parameter allows an administrator
+ * to override that
+ */
+ else if (!memcmp(from, "noeasyrclm", 10)) {
+ hotadd_zone_offset = ZONE_HIGHMEM;
}

next_char:
@@ -1550,6 +1564,13 @@ void __init setup_arch(char **cmdline_p)
tsc_init();
}

+struct zone *get_zone_for_hotadd(struct pglist_data *pgdata) {
+ if (unlikely(hotadd_zone_offset == -1))
+ hotadd_zone_offset = ZONE_HIGHMEM;
+
+ return &pgdata->node_zones[hotadd_zone_offset];
+}
+
#include "setup_arch_post.h"
/*
* Local Variables:
diff -rup -X /usr/src/patchset-0.5/bin//dontdiff linux-2.6.16-rc3-mm1-104_ppc64coremem/arch/i386/mm/init.c linux-2.6.16-rc3-mm1-106_zonechoose/arch/i386/mm/init.c
--- linux-2.6.16-rc3-mm1-104_ppc64coremem/arch/i386/mm/init.c 2006-02-16 09:50:41.000000000 +0000
+++ linux-2.6.16-rc3-mm1-106_zonechoose/arch/i386/mm/init.c 2006-02-17 09:44:16.000000000 +0000
@@ -655,7 +655,7 @@ void __init mem_init(void)
int add_memory(u64 start, u64 size)
{
struct pglist_data *pgdata = &contig_page_data;
- struct zone *zone = pgdata->node_zones + MAX_NR_ZONES-1;
+ struct zone *zone = get_zone_for_hotadd(pgdata);
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;

diff -rup -X /usr/src/patchset-0.5/bin//dontdiff linux-2.6.16-rc3-mm1-104_ppc64coremem/arch/powerpc/mm/mem.c linux-2.6.16-rc3-mm1-106_zonechoose/arch/powerpc/mm/mem.c
--- linux-2.6.16-rc3-mm1-104_ppc64coremem/arch/powerpc/mm/mem.c 2006-02-16 09:50:42.000000000 +0000
+++ linux-2.6.16-rc3-mm1-106_zonechoose/arch/powerpc/mm/mem.c 2006-02-17 09:44:16.000000000 +0000
@@ -129,7 +129,7 @@ int __devinit add_memory(u64 start, u64
create_section_mapping(start, start + size);

/* this should work for most non-highmem platforms */
- zone = pgdata->node_zones;
+ zone = get_zone_for_hotadd(pgdata);

return __add_pages(zone, start_pfn, nr_pages);

diff -rup -X /usr/src/patchset-0.5/bin//dontdiff linux-2.6.16-rc3-mm1-104_ppc64coremem/arch/powerpc/mm/numa.c linux-2.6.16-rc3-mm1-106_zonechoose/arch/powerpc/mm/numa.c
--- linux-2.6.16-rc3-mm1-104_ppc64coremem/arch/powerpc/mm/numa.c 2006-02-17 09:43:30.000000000 +0000
+++ linux-2.6.16-rc3-mm1-106_zonechoose/arch/powerpc/mm/numa.c 2006-02-17 09:44:16.000000000 +0000
@@ -39,6 +39,7 @@ EXPORT_SYMBOL(node_data);
static bootmem_data_t __initdata plat_node_bdata[MAX_NUMNODES];
static int min_common_depth;
static int n_mem_addr_cells, n_mem_size_cells;
+static int hotadd_zone_offset = -1;

/*
* We need somewhere to store start/end/node for each region until we have
@@ -736,6 +737,13 @@ void __init paging_init(void)
opt += 11;
core_mem_size = memparse(opt, &opt);
core_mem_pfn = core_mem_size >> PAGE_SHIFT;
+ hotadd_zone_offset = ZONE_EASYRCLM;
+ }
+
+ /* Check if the administrator requests only ZONE_DMA be used */
+ opt = strstr(cmd_line, "noeasyrclm");
+ if (opt) {
+ hotadd_zone_offset = ZONE_DMA;
}

for_each_online_node(nid) {
@@ -847,4 +855,12 @@ got_numa_domain:
}
return numa_domain;
}
+
+struct zone *get_zone_for_hotadd(struct pglist_data *pgdata)
+{
+ if (unlikely(hotadd_zone_offset == -1))
+ hotadd_zone_offset = ZONE_DMA;
+
+ return &pgdata->node_zones[hotadd_zone_offset];
+}
#endif /* CONFIG_MEMORY_HOTPLUG */
diff -rup -X /usr/src/patchset-0.5/bin//dontdiff linux-2.6.16-rc3-mm1-104_ppc64coremem/include/linux/memory_hotplug.h linux-2.6.16-rc3-mm1-106_zonechoose/include/linux/memory_hotplug.h
--- linux-2.6.16-rc3-mm1-104_ppc64coremem/include/linux/memory_hotplug.h 2006-02-13 00:27:25.000000000 +0000
+++ linux-2.6.16-rc3-mm1-106_zonechoose/include/linux/memory_hotplug.h 2006-02-17 09:44:16.000000000 +0000
@@ -57,6 +57,7 @@ extern void online_page(struct page *pag
extern int add_memory(u64 start, u64 size);
extern int remove_memory(u64 start, u64 size);
extern int online_pages(unsigned long, unsigned long);
+extern struct zone *get_zone_for_hotadd(struct pglist_data *);

/* reasonably generic interface to expand the physical pages in a zone */
extern int __add_pages(struct zone *zone, unsigned long start_pfn,