[PATCH 4/5] [PPC] update lmb for hotplug memory add/remove

Badari Pulavarty pbadari at us.ibm.com
Fri Mar 28 11:39:19 EST 2008


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 <pbadari at us.ibm.com>
---
 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,





More information about the Linuxppc-dev mailing list