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-rw-r--r--mm/Kconfig8
-rw-r--r--mm/Makefile7
-rw-r--r--mm/percpu-km.c2
-rw-r--r--mm/percpu.c60
-rw-r--r--mm/percpu_up.c30
5 files changed, 66 insertions, 41 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index f4e516e9c37c..01a57447a410 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -301,3 +301,11 @@ config NOMMU_INITIAL_TRIM_EXCESS
of 1 says that all excess pages should be trimmed.
See Documentation/nommu-mmap.txt for more information.
+
+#
+# UP and nommu archs use km based percpu allocator
+#
+config NEED_PER_CPU_KM
+ depends on !SMP
+ bool
+ default y
diff --git a/mm/Makefile b/mm/Makefile
index 34b2546a9e37..f73f75a29f82 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -11,7 +11,7 @@ obj-y := bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \
maccess.o page_alloc.o page-writeback.o \
readahead.o swap.o truncate.o vmscan.o shmem.o \
prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \
- page_isolation.o mm_init.o mmu_context.o \
+ page_isolation.o mm_init.o mmu_context.o percpu.o \
$(mmu-y)
obj-y += init-mm.o
@@ -36,11 +36,6 @@ obj-$(CONFIG_FAILSLAB) += failslab.o
obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
obj-$(CONFIG_FS_XIP) += filemap_xip.o
obj-$(CONFIG_MIGRATION) += migrate.o
-ifdef CONFIG_SMP
-obj-y += percpu.o
-else
-obj-y += percpu_up.o
-endif
obj-$(CONFIG_QUICKLIST) += quicklist.o
obj-$(CONFIG_CGROUP_MEM_RES_CTLR) += memcontrol.o page_cgroup.o
obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o
diff --git a/mm/percpu-km.c b/mm/percpu-km.c
index df680855540a..7037bc73bfa4 100644
--- a/mm/percpu-km.c
+++ b/mm/percpu-km.c
@@ -27,7 +27,7 @@
* chunk size is not aligned. percpu-km code will whine about it.
*/
-#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
+#if defined(CONFIG_SMP) && defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
#error "contiguous percpu allocation is incompatible with paged first chunk"
#endif
diff --git a/mm/percpu.c b/mm/percpu.c
index 58c572b18b07..fa70122dfdd0 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -76,6 +76,7 @@
#define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
#define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */
+#ifdef CONFIG_SMP
/* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
#ifndef __addr_to_pcpu_ptr
#define __addr_to_pcpu_ptr(addr) \
@@ -89,6 +90,11 @@
(unsigned long)pcpu_base_addr - \
(unsigned long)__per_cpu_start)
#endif
+#else /* CONFIG_SMP */
+/* on UP, it's always identity mapped */
+#define __addr_to_pcpu_ptr(addr) (void __percpu *)(addr)
+#define __pcpu_ptr_to_addr(ptr) (void __force *)(ptr)
+#endif /* CONFIG_SMP */
struct pcpu_chunk {
struct list_head list; /* linked to pcpu_slot lists */
@@ -949,6 +955,7 @@ EXPORT_SYMBOL_GPL(free_percpu);
*/
bool is_kernel_percpu_address(unsigned long addr)
{
+#ifdef CONFIG_SMP
const size_t static_size = __per_cpu_end - __per_cpu_start;
void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
unsigned int cpu;
@@ -959,6 +966,8 @@ bool is_kernel_percpu_address(unsigned long addr)
if ((void *)addr >= start && (void *)addr < start + static_size)
return true;
}
+#endif
+ /* on UP, can't distinguish from other static vars, always false */
return false;
}
@@ -1066,6 +1075,8 @@ void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
free_bootmem(__pa(ai), ai->__ai_size);
}
+#if defined(CONFIG_SMP) && (defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
+ defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK))
/**
* pcpu_build_alloc_info - build alloc_info considering distances between CPUs
* @reserved_size: the size of reserved percpu area in bytes
@@ -1220,6 +1231,8 @@ static struct pcpu_alloc_info * __init pcpu_build_alloc_info(
return ai;
}
+#endif /* CONFIG_SMP && (CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK ||
+ CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK) */
/**
* pcpu_dump_alloc_info - print out information about pcpu_alloc_info
@@ -1363,7 +1376,9 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
/* sanity checks */
PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
+#ifdef CONFIG_SMP
PCPU_SETUP_BUG_ON(!ai->static_size);
+#endif
PCPU_SETUP_BUG_ON(!base_addr);
PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
PCPU_SETUP_BUG_ON(ai->unit_size & ~PAGE_MASK);
@@ -1488,6 +1503,8 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
return 0;
}
+#ifdef CONFIG_SMP
+
const char *pcpu_fc_names[PCPU_FC_NR] __initdata = {
[PCPU_FC_AUTO] = "auto",
[PCPU_FC_EMBED] = "embed",
@@ -1758,8 +1775,9 @@ out_free_ar:
}
#endif /* CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK */
+#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
/*
- * Generic percpu area setup.
+ * Generic SMP percpu area setup.
*
* The embedding helper is used because its behavior closely resembles
* the original non-dynamic generic percpu area setup. This is
@@ -1770,7 +1788,6 @@ out_free_ar:
* on the physical linear memory mapping which uses large page
* mappings on applicable archs.
*/
-#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
EXPORT_SYMBOL(__per_cpu_offset);
@@ -1799,13 +1816,48 @@ void __init setup_per_cpu_areas(void)
PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL,
pcpu_dfl_fc_alloc, pcpu_dfl_fc_free);
if (rc < 0)
- panic("Failed to initialized percpu areas.");
+ panic("Failed to initialize percpu areas.");
delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
for_each_possible_cpu(cpu)
__per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
}
-#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
+#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
+
+#else /* CONFIG_SMP */
+
+/*
+ * UP percpu area setup.
+ *
+ * UP always uses km-based percpu allocator with identity mapping.
+ * Static percpu variables are indistinguishable from the usual static
+ * variables and don't require any special preparation.
+ */
+void __init setup_per_cpu_areas(void)
+{
+ const size_t unit_size =
+ roundup_pow_of_two(max_t(size_t, PCPU_MIN_UNIT_SIZE,
+ PERCPU_DYNAMIC_RESERVE));
+ struct pcpu_alloc_info *ai;
+ void *fc;
+
+ ai = pcpu_alloc_alloc_info(1, 1);
+ fc = __alloc_bootmem(unit_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
+ if (!ai || !fc)
+ panic("Failed to allocate memory for percpu areas.");
+
+ ai->dyn_size = unit_size;
+ ai->unit_size = unit_size;
+ ai->atom_size = unit_size;
+ ai->alloc_size = unit_size;
+ ai->groups[0].nr_units = 1;
+ ai->groups[0].cpu_map[0] = 0;
+
+ if (pcpu_setup_first_chunk(ai, fc) < 0)
+ panic("Failed to initialize percpu areas.");
+}
+
+#endif /* CONFIG_SMP */
/*
* First and reserved chunks are initialized with temporary allocation
diff --git a/mm/percpu_up.c b/mm/percpu_up.c
deleted file mode 100644
index db884fae5721..000000000000
--- a/mm/percpu_up.c
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
- * mm/percpu_up.c - dummy percpu memory allocator implementation for UP
- */
-
-#include <linux/module.h>
-#include <linux/percpu.h>
-#include <linux/slab.h>
-
-void __percpu *__alloc_percpu(size_t size, size_t align)
-{
- /*
- * Can't easily make larger alignment work with kmalloc. WARN
- * on it. Larger alignment should only be used for module
- * percpu sections on SMP for which this path isn't used.
- */
- WARN_ON_ONCE(align > SMP_CACHE_BYTES);
- return (void __percpu __force *)kzalloc(size, GFP_KERNEL);
-}
-EXPORT_SYMBOL_GPL(__alloc_percpu);
-
-void free_percpu(void __percpu *p)
-{
- kfree(this_cpu_ptr(p));
-}
-EXPORT_SYMBOL_GPL(free_percpu);
-
-phys_addr_t per_cpu_ptr_to_phys(void *addr)
-{
- return __pa(addr);
-}