[PATCH 20/20] powerpc64: convert to dynamic percpu allocator

Tejun Heo
2009-07-21T10:26:19Z

Now that percpu allows arbitrary embedding of the first chunk,
powerpc64 can easily be converted to dynamic percpu allocator.
Convert it. powerpc supports several large page sizes. Cap atom_size
at 1M. There isn't much to gain by going above that anyway.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
arch/powerpc/Kconfig | 4 +-
arch/powerpc/kernel/setup_64.c | 61 +++++++++++++++++++++++++++++----------
2 files changed, 47 insertions(+), 18 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 61bbffa..2c42e15 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -46,10 +46,10 @@ config GENERIC_HARDIRQS_NO__DO_IRQ
bool
default y

-config HAVE_LEGACY_PER_CPU_AREA
+config HAVE_SETUP_PER_CPU_AREA
def_bool PPC64

-config HAVE_SETUP_PER_CPU_AREA
+config NEED_PER_CPU_EMBED_FIRST_CHUNK
def_bool PPC64

config IRQ_PER_CPU
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 1f68160..aa6e450 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -57,6 +57,7 @@
#include <asm/cache.h>
#include <asm/page.h>
#include <asm/mmu.h>
+#include <asm/mmu-hash64.h>
#include <asm/firmware.h>
#include <asm/xmon.h>
#include <asm/udbg.h>
@@ -569,25 +570,53 @@ void cpu_die(void)
}

#ifdef CONFIG_SMP
-void __init setup_per_cpu_areas(void)
+#define PCPU_DYN_SIZE ()
+
+static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align)
{
- int i;
- unsigned long size;
- char *ptr;
-
- /* Copy section for each CPU (we discard the original) */
- size = ALIGN(__per_cpu_end - __per_cpu_start, PAGE_SIZE);
-#ifdef CONFIG_MODULES
- if (size < PERCPU_ENOUGH_ROOM)
- size = PERCPU_ENOUGH_ROOM;
-#endif
+ return __alloc_bootmem_node(NODE_DATA(cpu_to_node(cpu)), size, align,
+ __pa(MAX_DMA_ADDRESS));
+}

- for_each_possible_cpu(i) {
- ptr = alloc_bootmem_pages_node(NODE_DATA(cpu_to_node(i)), size);
+static void __init pcpu_fc_free(void *ptr, size_t size)
+{
+ free_bootmem(__pa(ptr), size);
+}

- paca[i].data_offset = ptr - __per_cpu_start;
- memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
- }
+static int pcpu_cpu_distance(unsigned int from, unsigned int to)
+{
+ if (cpu_to_node(from) == cpu_to_node(to))
+ return LOCAL_DISTANCE;
+ else
+ return REMOTE_DISTANCE;
+}
+
+void __init setup_per_cpu_areas(void)
+{
+ const size_t dyn_size = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE;
+ size_t atom_size;
+ unsigned long delta;
+ unsigned int cpu;
+ int rc;
+
+ /*
+ * Linear mapping is one of 4K, 1M and 16M. For 4K, no need
+ * to group units. For larger mappings, use 1M atom which
+ * should be large enough to contain a number of units.
+ */
+ if (mmu_linear_psize == MMU_PAGE_4K)
+ atom_size = PAGE_SIZE;
+ else
+ atom_size = 1 << 20;
+
+ rc = pcpu_embed_first_chunk(0, dyn_size, atom_size, pcpu_cpu_distance,
+ pcpu_fc_alloc, pcpu_fc_free);
+ if (rc < 0)
+ panic("cannot initialize percpu area (err=%d)", rc);
+
+ delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
+ for_each_possible_cpu(cpu)
+ paca[cpu].data_offset = delta + pcpu_unit_offsets[cpu];
}
#endif

--
1.6.0.2