Hi Andrew & Paul,
Here are the updates for hotplug memory remove. Most changes are
PPC specific, but I would like these to be included in next -mm
for easy testing and review, before including in Paul's tree.
eHEA driver folks are verifying if the exported interface
walk_memory_resource() is good enough for their needs. And also,
we are verifying the code on x86_64. Once that is done, we may
be able to cleanup some of the code (make remove_memory() arch
generic).
[PATCH 1/5] generic __remove_pages() support
[PATCH 2/5] [PPC] htab_remove_mapping() error handling
[PATCH 3/5] [PPC] hotplug memory notifications for ppc
[PATCH 4/5] [PPC] update lmb for hotplug memory add/remove
[PATCH 5/5] [PPC] provide walk_memory_resource() for ppc
Testing: All the patches are tested on p-series LPAR configuration,
writing to /sysfs & /proc, through DLPAR tools and through HMC.
Testing on x86_64 needs more work.
Thanks,
Badari
Generic helper function to remove section mappings and sysfs entries
for the section of the memory we are removing. offline_pages() correctly
adjusted zone and marked the pages reserved.
TODO: Yasunori Goto is working on patches to freeup allocations from bootmem.
Signed-off-by: Badari Pulavarty <[email protected]>
---
include/linux/memory_hotplug.h | 6 +++-
mm/memory_hotplug.c | 55 +++++++++++++++++++++++++++++++++++++++++
mm/sparse.c | 45 +++++++++++++++++++++++++++++++--
3 files changed, 102 insertions(+), 4 deletions(-)
Index: linux-2.6.25-rc5/mm/memory_hotplug.c
===================================================================
--- linux-2.6.25-rc5.orig/mm/memory_hotplug.c 2008-03-21 07:00:37.000000000 -0800
+++ linux-2.6.25-rc5/mm/memory_hotplug.c 2008-03-25 15:03:58.000000000 -0800
@@ -102,6 +102,25 @@ static int __add_section(struct zone *zo
return register_new_memory(__pfn_to_section(phys_start_pfn));
}
+static int __remove_section(struct zone *zone, struct mem_section *ms)
+{
+ unsigned long flags;
+ struct pglist_data *pgdat = zone->zone_pgdat;
+ int ret = -EINVAL;
+
+ if (!valid_section(ms))
+ return ret;
+
+ ret = unregister_memory_section(ms);
+ if (ret)
+ return ret;
+
+ pgdat_resize_lock(pgdat, &flags);
+ sparse_remove_one_section(zone, ms);
+ pgdat_resize_unlock(pgdat, &flags);
+ return 0;
+}
+
/*
* Reasonably generic function for adding memory. It is
* expected that archs that support memory hotplug will
@@ -135,6 +154,42 @@ int __add_pages(struct zone *zone, unsig
}
EXPORT_SYMBOL_GPL(__add_pages);
+/**
+ * __remove_pages() - remove sections of pages from a zone
+ * @zone: zone from which pages need to be removed
+ * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
+ * @nr_pages: number of pages to remove (must be multiple of section size)
+ *
+ * Generic helper function to remove section mappings and sysfs entries
+ * for the section of the memory we are removing. Caller needs to make
+ * sure that pages are marked reserved and zones are adjust properly by
+ * calling offline_pages().
+ */
+int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
+ unsigned long nr_pages)
+{
+ unsigned long i, ret = 0;
+ int sections_to_remove;
+
+ /*
+ * We can only remove entire sections
+ */
+ BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
+ BUG_ON(nr_pages % PAGES_PER_SECTION);
+
+ release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
+
+ sections_to_remove = nr_pages / PAGES_PER_SECTION;
+ for (i = 0; i < sections_to_remove; i++) {
+ unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
+ ret = __remove_section(zone, __pfn_to_section(pfn));
+ if (ret)
+ break;
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__remove_pages);
+
static void grow_zone_span(struct zone *zone,
unsigned long start_pfn, unsigned long end_pfn)
{
Index: linux-2.6.25-rc5/mm/sparse.c
===================================================================
--- linux-2.6.25-rc5.orig/mm/sparse.c 2008-03-21 07:00:37.000000000 -0800
+++ linux-2.6.25-rc5/mm/sparse.c 2008-03-25 13:59:51.000000000 -0800
@@ -198,12 +198,13 @@ static unsigned long sparse_encode_mem_m
}
/*
- * We need this if we ever free the mem_maps. While not implemented yet,
- * this function is included for parity with its sibling.
+ * Decode mem_map from the coded memmap
*/
-static __attribute((unused))
+static
struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
{
+ /* mask off the extra low bits of information */
+ coded_mem_map &= SECTION_MAP_MASK;
return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
}
@@ -363,6 +364,28 @@ static void __kfree_section_memmap(struc
}
#endif /* CONFIG_SPARSEMEM_VMEMMAP */
+static void free_section_usemap(struct page *memmap, unsigned long *usemap)
+{
+ if (!usemap)
+ return;
+
+ /*
+ * Check to see if allocation came from hot-plug-add
+ */
+ if (PageSlab(virt_to_page(usemap))) {
+ kfree(usemap);
+ if (memmap)
+ __kfree_section_memmap(memmap, PAGES_PER_SECTION);
+ return;
+ }
+
+ /*
+ * TODO: Allocations came from bootmem - how do I free up ?
+ */
+ printk(KERN_WARNING "Not freeing up allocations from bootmem "
+ "- leaking memory\n");
+}
+
/*
* returns the number of sections whose mem_maps were properly
* set. If this is <=0, then that means that the passed-in
@@ -415,4 +438,20 @@ out:
}
return ret;
}
+
+void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
+{
+ struct page *memmap = NULL;
+ unsigned long *usemap = NULL;
+
+ if (ms->section_mem_map) {
+ usemap = ms->pageblock_flags;
+ memmap = sparse_decode_mem_map(ms->section_mem_map,
+ __section_nr(ms));
+ ms->section_mem_map = 0;
+ ms->pageblock_flags = NULL;
+ }
+
+ free_section_usemap(memmap, usemap);
+}
#endif
Index: linux-2.6.25-rc5/include/linux/memory_hotplug.h
===================================================================
--- linux-2.6.25-rc5.orig/include/linux/memory_hotplug.h 2008-03-21 07:00:36.000000000 -0800
+++ linux-2.6.25-rc5/include/linux/memory_hotplug.h 2008-03-25 13:59:51.000000000 -0800
@@ -8,6 +8,7 @@
struct page;
struct zone;
struct pglist_data;
+struct mem_section;
#ifdef CONFIG_MEMORY_HOTPLUG
/*
@@ -64,9 +65,11 @@ extern int offline_pages(unsigned long,
/* reasonably generic interface to expand the physical pages in a zone */
extern int __add_pages(struct zone *zone, unsigned long start_pfn,
unsigned long nr_pages);
+extern int __remove_pages(struct zone *zone, unsigned long start_pfn,
+ unsigned long nr_pages);
/*
- * Walk thorugh all memory which is registered as resource.
+ * Walk through all memory which is registered as resource.
* arg is (start_pfn, nr_pages, private_arg_pointer)
*/
extern int walk_memory_resource(unsigned long start_pfn,
@@ -188,5 +191,6 @@ extern int arch_add_memory(int nid, u64
extern int remove_memory(u64 start, u64 size);
extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
int nr_pages);
+extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
#endif /* __LINUX_MEMORY_HOTPLUG_H */
If the sub-arch doesn't support hpte_removebolted(), gracefully
return failure rather than success.
Signed-off-by: Badari Pulavarty <[email protected]>
---
arch/powerpc/mm/hash_utils_64.c | 14 +++++++++-----
include/asm-powerpc/sparsemem.h | 2 +-
2 files changed, 10 insertions(+), 6 deletions(-)
Index: linux-2.6.25-rc3/arch/powerpc/mm/hash_utils_64.c
===================================================================
--- linux-2.6.25-rc3.orig/arch/powerpc/mm/hash_utils_64.c 2008-03-05 10:14:28.000000000 -0800
+++ linux-2.6.25-rc3/arch/powerpc/mm/hash_utils_64.c 2008-03-05 10:18:55.000000000 -0800
@@ -192,7 +192,7 @@ int htab_bolt_mapping(unsigned long vsta
return ret < 0 ? ret : 0;
}
-static void htab_remove_mapping(unsigned long vstart, unsigned long vend,
+static int htab_remove_mapping(unsigned long vstart, unsigned long vend,
int psize, int ssize)
{
unsigned long vaddr;
@@ -202,12 +202,15 @@ static void htab_remove_mapping(unsigned
step = 1 << shift;
if (!ppc_md.hpte_removebolted) {
- printk("Sub-arch doesn't implement hpte_removebolted\n");
- return;
+ printk(KERN_WARNING "Sub-arch doesn't implement "
+ "hpte_removebolted\n");
+ return -EINVAL;
}
for (vaddr = vstart; vaddr < vend; vaddr += step)
ppc_md.hpte_removebolted(vaddr, psize, ssize);
+
+ return 0;
}
static int __init htab_dt_scan_seg_sizes(unsigned long node,
@@ -449,9 +452,10 @@ void create_section_mapping(unsigned lon
mmu_linear_psize, mmu_kernel_ssize));
}
-void remove_section_mapping(unsigned long start, unsigned long end)
+int remove_section_mapping(unsigned long start, unsigned long end)
{
- htab_remove_mapping(start, end, mmu_linear_psize, mmu_kernel_ssize);
+ return htab_remove_mapping(start, end, mmu_linear_psize,
+ mmu_kernel_ssize);
}
#endif /* CONFIG_MEMORY_HOTPLUG */
Index: linux-2.6.25-rc3/include/asm-powerpc/sparsemem.h
===================================================================
--- linux-2.6.25-rc3.orig/include/asm-powerpc/sparsemem.h 2008-03-05 10:14:31.000000000 -0800
+++ linux-2.6.25-rc3/include/asm-powerpc/sparsemem.h 2008-03-05 10:19:09.000000000 -0800
@@ -15,7 +15,7 @@
#ifdef CONFIG_MEMORY_HOTPLUG
extern void create_section_mapping(unsigned long start, unsigned long end);
-extern void remove_section_mapping(unsigned long start, unsigned long end);
+extern int remove_section_mapping(unsigned long start, unsigned long end);
#ifdef CONFIG_NUMA
extern int hot_add_scn_to_nid(unsigned long scn_addr);
#else
Hotplug memory notifier for ppc64. This gets invoked by writing
the device-node that needs to be removed to /proc/ppc64/ofdt.
We need to adjust the sections and remove sysfs entries by
calling __remove_pages(). Then call arch specific code to
get rid of htab mappings for the section of memory.
Signed-off-by: Badari Pulavarty <[email protected]>
Reviewed-by: Michael Ellerman <[email protected]>
---
arch/powerpc/platforms/pseries/Makefile | 1
arch/powerpc/platforms/pseries/hotplug-memory.c | 98 ++++++++++++++++++++++++
2 files changed, 99 insertions(+)
Index: linux-2.6.25-rc2/arch/powerpc/platforms/pseries/hotplug-memory.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.25-rc2/arch/powerpc/platforms/pseries/hotplug-memory.c 2008-02-29 09:25:14.000000000 -0800
@@ -0,0 +1,98 @@
+/*
+ * pseries Memory Hotplug infrastructure.
+ *
+ * Copyright (C) 2008 Badari Pulavarty, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/of.h>
+#include <asm/firmware.h>
+#include <asm/machdep.h>
+#include <asm/pSeries_reconfig.h>
+
+static int pseries_remove_memory(struct device_node *np)
+{
+ const char *type;
+ const unsigned int *my_index;
+ const unsigned int *regs;
+ u64 start_pfn, start;
+ struct zone *zone;
+ int ret = -EINVAL;
+
+ /*
+ * Check to see if we are actually removing memory
+ */
+ type = of_get_property(np, "device_type", NULL);
+ if (type == NULL || strcmp(type, "memory") != 0)
+ return 0;
+
+ /*
+ * Find the memory index and size of the removing section
+ */
+ my_index = of_get_property(np, "ibm,my-drc-index", NULL);
+ if (!my_index)
+ return ret;
+
+ regs = of_get_property(np, "reg", NULL);
+ if (!regs)
+ return ret;
+
+ start_pfn = section_nr_to_pfn(*my_index & 0xffff);
+ zone = page_zone(pfn_to_page(start_pfn));
+
+ /*
+ * Remove section mappings and sysfs entries for the
+ * section of the memory we are removing.
+ *
+ * NOTE: Ideally, this should be done in generic code like
+ * remove_memory(). But remove_memory() gets called by writing
+ * to sysfs "state" file and we can't remove sysfs entries
+ * while writing to it. So we have to defer it to here.
+ */
+ ret = __remove_pages(zone, start_pfn, regs[3] >> PAGE_SHIFT);
+ if (ret)
+ return ret;
+
+ /*
+ * Remove htab bolted mappings for this section of memory
+ */
+ start = (unsigned long)__va(start_pfn << PAGE_SHIFT);
+ ret = remove_section_mapping(start, start + regs[3]);
+ return ret;
+}
+
+static int pseries_memory_notifier(struct notifier_block *nb,
+ unsigned long action, void *node)
+{
+ int err = NOTIFY_OK;
+
+ switch (action) {
+ case PSERIES_RECONFIG_ADD:
+ break;
+ case PSERIES_RECONFIG_REMOVE:
+ if (pseries_remove_memory(node))
+ err = NOTIFY_BAD;
+ break;
+ default:
+ err = NOTIFY_DONE;
+ break;
+ }
+ return err;
+}
+
+static struct notifier_block pseries_mem_nb = {
+ .notifier_call = pseries_memory_notifier,
+};
+
+static int __init pseries_memory_hotplug_init(void)
+{
+ if (firmware_has_feature(FW_FEATURE_LPAR))
+ pSeries_reconfig_notifier_register(&pseries_mem_nb);
+
+ return 0;
+}
+machine_device_initcall(pseries, pseries_memory_hotplug_init);
Index: linux-2.6.25-rc2/arch/powerpc/platforms/pseries/Makefile
===================================================================
--- linux-2.6.25-rc2.orig/arch/powerpc/platforms/pseries/Makefile 2008-02-28 08:15:53.000000000 -0800
+++ linux-2.6.25-rc2/arch/powerpc/platforms/pseries/Makefile 2008-02-28 08:17:57.000000000 -0800
@@ -14,6 +14,7 @@ obj-$(CONFIG_PCI) += pci.o pci_dlpar.o
obj-$(CONFIG_PCI_MSI) += msi.o
obj-$(CONFIG_HOTPLUG_CPU) += hotplug-cpu.o
+obj-$(CONFIG_MEMORY_HOTPLUG) += hotplug-memory.o
obj-$(CONFIG_HVC_CONSOLE) += hvconsole.o
obj-$(CONFIG_HVCS) += hvcserver.o
ppc kernel maintains information about logical memory blocks in
lmb.memory structure at the boot time. Its not updated for
hotplug memory add/remove. hotplug memory notifier for memory
add/remove now updates lmb.memory.
This information is useful for eHEA driver to find out the memory
layout and holes.
NOTE: No special locking is needed for lmb_add() and lmb_remove().
Calls to these are serialized by caller. (pSeries_reconfig_chain).
Signed-off-by: Badari Pulavarty <[email protected]>
---
arch/powerpc/platforms/pseries/hotplug-memory.c | 43 +++++++++++++++
include/linux/lmb.h | 3 -
lib/lmb.c | 66 ++++++++++++++++++++----
3 files changed, 102 insertions(+), 10 deletions(-)
Index: linux-2.6.25-rc3/lib/lmb.c
===================================================================
--- linux-2.6.25-rc3.orig/lib/lmb.c 2008-03-05 10:44:29.000000000 -0800
+++ linux-2.6.25-rc3/lib/lmb.c 2008-03-05 10:44:56.000000000 -0800
@@ -54,14 +54,13 @@ void lmb_dump_all(void)
#endif /* DEBUG */
}
-static unsigned long __init lmb_addrs_overlap(u64 base1,
- u64 size1, u64 base2, u64 size2)
+static unsigned long lmb_addrs_overlap(u64 base1, u64 size1, u64 base2,
+ u64 size2)
{
return ((base1 < (base2+size2)) && (base2 < (base1+size1)));
}
-static long __init lmb_addrs_adjacent(u64 base1, u64 size1,
- u64 base2, u64 size2)
+static long lmb_addrs_adjacent(u64 base1, u64 size1, u64 base2, u64 size2)
{
if (base2 == base1 + size1)
return 1;
@@ -71,7 +70,7 @@ static long __init lmb_addrs_adjacent(u6
return 0;
}
-static long __init lmb_regions_adjacent(struct lmb_region *rgn,
+static long lmb_regions_adjacent(struct lmb_region *rgn,
unsigned long r1, unsigned long r2)
{
u64 base1 = rgn->region[r1].base;
@@ -82,7 +81,7 @@ static long __init lmb_regions_adjacent(
return lmb_addrs_adjacent(base1, size1, base2, size2);
}
-static void __init lmb_remove_region(struct lmb_region *rgn, unsigned long r)
+static void lmb_remove_region(struct lmb_region *rgn, unsigned long r)
{
unsigned long i;
@@ -94,7 +93,7 @@ static void __init lmb_remove_region(str
}
/* Assumption: base addr of region 1 < base addr of region 2 */
-static void __init lmb_coalesce_regions(struct lmb_region *rgn,
+static void lmb_coalesce_regions(struct lmb_region *rgn,
unsigned long r1, unsigned long r2)
{
rgn->region[r1].size += rgn->region[r2].size;
@@ -129,7 +128,7 @@ void __init lmb_analyze(void)
}
/* This routine called with relocation disabled. */
-static long __init lmb_add_region(struct lmb_region *rgn, u64 base, u64 size)
+static long lmb_add_region(struct lmb_region *rgn, u64 base, u64 size)
{
unsigned long coalesced = 0;
long adjacent, i;
@@ -195,7 +194,7 @@ static long __init lmb_add_region(struct
}
/* This routine may be called with relocation disabled. */
-long __init lmb_add(u64 base, u64 size)
+long lmb_add(u64 base, u64 size)
{
struct lmb_region *_rgn = &(lmb.memory);
@@ -207,6 +206,55 @@ long __init lmb_add(u64 base, u64 size)
}
+long lmb_remove(u64 base, u64 size)
+{
+ struct lmb_region *rgn = &(lmb.memory);
+ u64 rgnbegin, rgnend;
+ u64 end = base + size;
+ int i;
+
+ rgnbegin = rgnend = 0; /* supress gcc warnings */
+
+ /* Find the region where (base, size) belongs to */
+ for (i=0; i < rgn->cnt; i++) {
+ rgnbegin = rgn->region[i].base;
+ rgnend = rgnbegin + rgn->region[i].size;
+
+ if ((rgnbegin <= base) && (end <= rgnend))
+ break;
+ }
+
+ /* Didn't find the region */
+ if (i == rgn->cnt)
+ return -1;
+
+ /* Check to see if we are removing entire region */
+ if ((rgnbegin == base) && (rgnend == end)) {
+ lmb_remove_region(rgn, i);
+ return 0;
+ }
+
+ /* Check to see if region is matching at the front */
+ if (rgnbegin == base) {
+ rgn->region[i].base = end;
+ rgn->region[i].size -= size;
+ return 0;
+ }
+
+ /* Check to see if the region is matching at the end */
+ if (rgnend == end) {
+ rgn->region[i].size -= size;
+ return 0;
+ }
+
+ /*
+ * We need to split the entry - adjust the current one to the
+ * beginging of the hole and add the region after hole.
+ */
+ rgn->region[i].size = base - rgn->region[i].base;
+ return lmb_add_region(rgn, end, rgnend - end);
+}
+
long __init lmb_reserve(u64 base, u64 size)
{
struct lmb_region *_rgn = &(lmb.reserved);
Index: linux-2.6.25-rc3/arch/powerpc/platforms/pseries/hotplug-memory.c
===================================================================
--- linux-2.6.25-rc3.orig/arch/powerpc/platforms/pseries/hotplug-memory.c 2008-03-05 10:44:51.000000000 -0800
+++ linux-2.6.25-rc3/arch/powerpc/platforms/pseries/hotplug-memory.c 2008-03-05 10:45:06.000000000 -0800
@@ -10,6 +10,7 @@
*/
#include <linux/of.h>
+#include <linux/lmb.h>
#include <asm/firmware.h>
#include <asm/machdep.h>
#include <asm/pSeries_reconfig.h>
@@ -58,6 +59,11 @@ static int pseries_remove_memory(struct
return ret;
/*
+ * Update memory regions for memory remove
+ */
+ lmb_remove(start_pfn << PAGE_SHIFT, regs[3]);
+
+ /*
* Remove htab bolted mappings for this section of memory
*/
start = (unsigned long)__va(start_pfn << PAGE_SHIFT);
@@ -65,6 +71,41 @@ static int pseries_remove_memory(struct
return ret;
}
+static int pseries_add_memory(struct device_node *np)
+{
+ const char *type;
+ const unsigned int *my_index;
+ const unsigned int *regs;
+ u64 start_pfn;
+ int ret = -EINVAL;
+
+ /*
+ * Check to see if we are actually adding memory
+ */
+ type = of_get_property(np, "device_type", NULL);
+ if (type == NULL || strcmp(type, "memory") != 0)
+ return 0;
+
+ /*
+ * Find the memory index and size of the removing section
+ */
+ my_index = of_get_property(np, "ibm,my-drc-index", NULL);
+ if (!my_index)
+ return ret;
+
+ regs = of_get_property(np, "reg", NULL);
+ if (!regs)
+ return ret;
+
+ start_pfn = section_nr_to_pfn(*my_index & 0xffff);
+
+ /*
+ * Update memory region to represent the memory add
+ */
+ lmb_add(start_pfn << PAGE_SHIFT, regs[3]);
+ return 0;
+}
+
static int pseries_memory_notifier(struct notifier_block *nb,
unsigned long action, void *node)
{
@@ -72,6 +113,8 @@ static int pseries_memory_notifier(struc
switch (action) {
case PSERIES_RECONFIG_ADD:
+ if (pseries_add_memory(node))
+ err = NOTIFY_BAD;
break;
case PSERIES_RECONFIG_REMOVE:
if (pseries_remove_memory(node))
Index: linux-2.6.25-rc3/include/linux/lmb.h
===================================================================
--- linux-2.6.25-rc3.orig/include/linux/lmb.h 2008-03-05 10:44:29.000000000 -0800
+++ linux-2.6.25-rc3/include/linux/lmb.h 2008-03-05 10:44:56.000000000 -0800
@@ -40,7 +40,8 @@ extern struct lmb lmb;
extern void __init lmb_init(void);
extern void __init lmb_analyze(void);
-extern long __init lmb_add(u64 base, u64 size);
+extern long lmb_add(u64 base, u64 size);
+extern long lmb_remove(u64 base, u64 size);
extern long __init lmb_reserve(u64 base, u64 size);
extern u64 __init lmb_alloc(u64 size, u64 align);
extern u64 __init lmb_alloc_base(u64 size,
Provide walk_memory_resource() for ppc64. PPC maintains
logic memory region mapping in lmb.memory structures. Walk
through these structures and do the callbacks for the
contiguous chunks.
Signed-off-by: Badari Pulavarty <[email protected]>
---
arch/powerpc/mm/mem.c | 30 +++++++++++++++++++++++-------
include/linux/lmb.h | 1 +
lib/lmb.c | 33 +++++++++++++++++++++++++++++++++
3 files changed, 57 insertions(+), 7 deletions(-)
Index: linux-2.6.25-rc3/lib/lmb.c
===================================================================
--- linux-2.6.25-rc3.orig/lib/lmb.c 2008-03-05 10:28:55.000000000 -0800
+++ linux-2.6.25-rc3/lib/lmb.c 2008-03-05 10:34:01.000000000 -0800
@@ -416,3 +416,36 @@ int __init lmb_is_reserved(u64 addr)
}
return 0;
}
+
+/*
+ * Given a <base, len>, find which memory regions belong to this range.
+ * Adjust the request and return a contiguous chunk.
+ */
+int lmb_find(struct lmb_property *res)
+{
+ int i;
+ u64 rstart, rend;
+
+ rstart = res->base;
+ rend = rstart + res->size - 1;
+
+ for (i = 0; i < lmb.memory.cnt; i++) {
+ u64 start = lmb.memory.region[i].base;
+ u64 end = start + lmb.memory.region[i].size - 1;
+
+ if (start > rend)
+ return -1;
+
+ if ((end >= rstart) && (start < rend)) {
+ /* adjust the request */
+ if (rstart < start)
+ rstart = start;
+ if (rend > end)
+ rend = end;
+ res->base = rstart;
+ res->size = rend - rstart + 1;
+ return 0;
+ }
+ }
+ return -1;
+}
Index: linux-2.6.25-rc3/arch/powerpc/mm/mem.c
===================================================================
--- linux-2.6.25-rc3.orig/arch/powerpc/mm/mem.c 2008-03-05 10:14:28.000000000 -0800
+++ linux-2.6.25-rc3/arch/powerpc/mm/mem.c 2008-03-05 10:32:16.000000000 -0800
@@ -148,19 +148,35 @@ out:
/*
* walk_memory_resource() needs to make sure there is no holes in a given
- * memory range. On PPC64, since this range comes from /sysfs, the range
- * is guaranteed to be valid, non-overlapping and can not contain any
- * holes. By the time we get here (memory add or remove), /proc/device-tree
- * is updated and correct. Only reason we need to check against device-tree
- * would be if we allow user-land to specify a memory range through a
- * system call/ioctl etc. instead of doing offline/online through /sysfs.
+ * memory range. PPC64 does not maintain the memory layout in /proc/iomem.
+ * Instead it maintains it in lmb.memory structures. Walk through the
+ * memory regions, find holes and callback for contiguous regions.
*/
int
walk_memory_resource(unsigned long start_pfn, unsigned long nr_pages, void *arg,
int (*func)(unsigned long, unsigned long, void *))
{
- return (*func)(start_pfn, nr_pages, arg);
+ struct lmb_property res;
+ unsigned long pfn, len;
+ u64 end;
+ int ret = -1;
+
+ res.base = (u64) start_pfn << PAGE_SHIFT;
+ res.size = (u64) nr_pages << PAGE_SHIFT;
+
+ end = res.base + res.size - 1;
+ while ((res.base < end) && (lmb_find(&res) >= 0)) {
+ pfn = (unsigned long)(res.base >> PAGE_SHIFT);
+ len = (unsigned long)(res.size >> PAGE_SHIFT);
+ ret = (*func)(pfn, len, arg);
+ if (ret)
+ break;
+ res.base += (res.size + 1);
+ res.size = (end - res.base + 1);
+ }
+ return ret;
}
+EXPORT_SYMBOL_GPL(walk_memory_resource);
#endif /* CONFIG_MEMORY_HOTPLUG */
Index: linux-2.6.25-rc3/include/linux/lmb.h
===================================================================
--- linux-2.6.25-rc3.orig/include/linux/lmb.h 2008-03-05 10:30:06.000000000 -0800
+++ linux-2.6.25-rc3/include/linux/lmb.h 2008-03-05 10:33:12.000000000 -0800
@@ -52,6 +52,7 @@ extern u64 __init lmb_phys_mem_size(void
extern u64 __init lmb_end_of_DRAM(void);
extern void __init lmb_enforce_memory_limit(u64 memory_limit);
extern int __init lmb_is_reserved(u64 addr);
+extern int lmb_find(struct lmb_property *res);
extern void lmb_dump_all(void);
Ok. Thanks.
Acked-by: Yasunori Goto <[email protected]>
> Generic helper function to remove section mappings and sysfs entries
> for the section of the memory we are removing. offline_pages() correctly
> adjusted zone and marked the pages reserved.
>
> TODO: Yasunori Goto is working on patches to freeup allocations from bootmem.
>
> Signed-off-by: Badari Pulavarty <[email protected]>
>
> ---
> include/linux/memory_hotplug.h | 6 +++-
> mm/memory_hotplug.c | 55 +++++++++++++++++++++++++++++++++++++++++
> mm/sparse.c | 45 +++++++++++++++++++++++++++++++--
> 3 files changed, 102 insertions(+), 4 deletions(-)
>
> Index: linux-2.6.25-rc5/mm/memory_hotplug.c
> ===================================================================
> --- linux-2.6.25-rc5.orig/mm/memory_hotplug.c 2008-03-21 07:00:37.000000000 -0800
> +++ linux-2.6.25-rc5/mm/memory_hotplug.c 2008-03-25 15:03:58.000000000 -0800
> @@ -102,6 +102,25 @@ static int __add_section(struct zone *zo
> return register_new_memory(__pfn_to_section(phys_start_pfn));
> }
>
> +static int __remove_section(struct zone *zone, struct mem_section *ms)
> +{
> + unsigned long flags;
> + struct pglist_data *pgdat = zone->zone_pgdat;
> + int ret = -EINVAL;
> +
> + if (!valid_section(ms))
> + return ret;
> +
> + ret = unregister_memory_section(ms);
> + if (ret)
> + return ret;
> +
> + pgdat_resize_lock(pgdat, &flags);
> + sparse_remove_one_section(zone, ms);
> + pgdat_resize_unlock(pgdat, &flags);
> + return 0;
> +}
> +
> /*
> * Reasonably generic function for adding memory. It is
> * expected that archs that support memory hotplug will
> @@ -135,6 +154,42 @@ int __add_pages(struct zone *zone, unsig
> }
> EXPORT_SYMBOL_GPL(__add_pages);
>
> +/**
> + * __remove_pages() - remove sections of pages from a zone
> + * @zone: zone from which pages need to be removed
> + * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
> + * @nr_pages: number of pages to remove (must be multiple of section size)
> + *
> + * Generic helper function to remove section mappings and sysfs entries
> + * for the section of the memory we are removing. Caller needs to make
> + * sure that pages are marked reserved and zones are adjust properly by
> + * calling offline_pages().
> + */
> +int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
> + unsigned long nr_pages)
> +{
> + unsigned long i, ret = 0;
> + int sections_to_remove;
> +
> + /*
> + * We can only remove entire sections
> + */
> + BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
> + BUG_ON(nr_pages % PAGES_PER_SECTION);
> +
> + release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
> +
> + sections_to_remove = nr_pages / PAGES_PER_SECTION;
> + for (i = 0; i < sections_to_remove; i++) {
> + unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
> + ret = __remove_section(zone, __pfn_to_section(pfn));
> + if (ret)
> + break;
> + }
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(__remove_pages);
> +
> static void grow_zone_span(struct zone *zone,
> unsigned long start_pfn, unsigned long end_pfn)
> {
> Index: linux-2.6.25-rc5/mm/sparse.c
> ===================================================================
> --- linux-2.6.25-rc5.orig/mm/sparse.c 2008-03-21 07:00:37.000000000 -0800
> +++ linux-2.6.25-rc5/mm/sparse.c 2008-03-25 13:59:51.000000000 -0800
> @@ -198,12 +198,13 @@ static unsigned long sparse_encode_mem_m
> }
>
> /*
> - * We need this if we ever free the mem_maps. While not implemented yet,
> - * this function is included for parity with its sibling.
> + * Decode mem_map from the coded memmap
> */
> -static __attribute((unused))
> +static
> struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
> {
> + /* mask off the extra low bits of information */
> + coded_mem_map &= SECTION_MAP_MASK;
> return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
> }
>
> @@ -363,6 +364,28 @@ static void __kfree_section_memmap(struc
> }
> #endif /* CONFIG_SPARSEMEM_VMEMMAP */
>
> +static void free_section_usemap(struct page *memmap, unsigned long *usemap)
> +{
> + if (!usemap)
> + return;
> +
> + /*
> + * Check to see if allocation came from hot-plug-add
> + */
> + if (PageSlab(virt_to_page(usemap))) {
> + kfree(usemap);
> + if (memmap)
> + __kfree_section_memmap(memmap, PAGES_PER_SECTION);
> + return;
> + }
> +
> + /*
> + * TODO: Allocations came from bootmem - how do I free up ?
> + */
> + printk(KERN_WARNING "Not freeing up allocations from bootmem "
> + "- leaking memory\n");
> +}
> +
> /*
> * returns the number of sections whose mem_maps were properly
> * set. If this is <=0, then that means that the passed-in
> @@ -415,4 +438,20 @@ out:
> }
> return ret;
> }
> +
> +void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
> +{
> + struct page *memmap = NULL;
> + unsigned long *usemap = NULL;
> +
> + if (ms->section_mem_map) {
> + usemap = ms->pageblock_flags;
> + memmap = sparse_decode_mem_map(ms->section_mem_map,
> + __section_nr(ms));
> + ms->section_mem_map = 0;
> + ms->pageblock_flags = NULL;
> + }
> +
> + free_section_usemap(memmap, usemap);
> +}
> #endif
> Index: linux-2.6.25-rc5/include/linux/memory_hotplug.h
> ===================================================================
> --- linux-2.6.25-rc5.orig/include/linux/memory_hotplug.h 2008-03-21 07:00:36.000000000 -0800
> +++ linux-2.6.25-rc5/include/linux/memory_hotplug.h 2008-03-25 13:59:51.000000000 -0800
> @@ -8,6 +8,7 @@
> struct page;
> struct zone;
> struct pglist_data;
> +struct mem_section;
>
> #ifdef CONFIG_MEMORY_HOTPLUG
> /*
> @@ -64,9 +65,11 @@ extern int offline_pages(unsigned long,
> /* reasonably generic interface to expand the physical pages in a zone */
> extern int __add_pages(struct zone *zone, unsigned long start_pfn,
> unsigned long nr_pages);
> +extern int __remove_pages(struct zone *zone, unsigned long start_pfn,
> + unsigned long nr_pages);
>
> /*
> - * Walk thorugh all memory which is registered as resource.
> + * Walk through all memory which is registered as resource.
> * arg is (start_pfn, nr_pages, private_arg_pointer)
> */
> extern int walk_memory_resource(unsigned long start_pfn,
> @@ -188,5 +191,6 @@ extern int arch_add_memory(int nid, u64
> extern int remove_memory(u64 start, u64 size);
> extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
> int nr_pages);
> +extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
>
> #endif /* __LINUX_MEMORY_HOTPLUG_H */
>
>
--
Yasunori Goto
On Mar 27, 2008, at 7:39 PM, Badari Pulavarty wrote:
> ppc kernel maintains information about logical memory blocks in
> lmb.memory structure at the boot time. Its not updated for
> hotplug memory add/remove. hotplug memory notifier for memory
> add/remove now updates lmb.memory.
>
> This information is useful for eHEA driver to find out the memory
> layout and holes.
>
> NOTE: No special locking is needed for lmb_add() and lmb_remove().
> Calls to these are serialized by caller. (pSeries_reconfig_chain).
>
> Signed-off-by: Badari Pulavarty <[email protected]>
> ---
> arch/powerpc/platforms/pseries/hotplug-memory.c | 43 +++++++++++++++
> include/linux/lmb.h | 3 -
> lib/lmb.c | 66 ++++++++++++++
> ++++++----
> 3 files changed, 102 insertions(+), 10 deletions(-)
How is lmb_remove different than lmb_alloc?
- k
Kumar Gala wrote:
>
> On Mar 27, 2008, at 7:39 PM, Badari Pulavarty wrote:
>> ppc kernel maintains information about logical memory blocks in
>> lmb.memory structure at the boot time. Its not updated for
>> hotplug memory add/remove. hotplug memory notifier for memory
>> add/remove now updates lmb.memory.
>>
>> This information is useful for eHEA driver to find out the memory
>> layout and holes.
>>
>> NOTE: No special locking is needed for lmb_add() and lmb_remove().
>> Calls to these are serialized by caller. (pSeries_reconfig_chain).
>>
>> Signed-off-by: Badari Pulavarty <[email protected]>
>> ---
>> arch/powerpc/platforms/pseries/hotplug-memory.c | 43 +++++++++++++++
>> include/linux/lmb.h | 3 -
>> lib/lmb.c | 66
>> ++++++++++++++++++++----
>> 3 files changed, 102 insertions(+), 10 deletions(-)
>
> How is lmb_remove different than lmb_alloc?
>
> - k
lmb_remove() can be used to punch a hole in to the existing memory block.
lmb_alloc() tries to allocate for a given alignment, I don't think it can
adjust the current entries. Isn't it ?
Thanks,
Badari