1 files changed, 1028 insertions, 290 deletions

diff --git a/mm/percpu.c b/mm/percpu.c
index 5fe37842e0ea..3f9f182f9b44 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -8,12 +8,13 @@
  *
  * This is percpu allocator which can handle both static and dynamic
  * areas.  Percpu areas are allocated in chunks in vmalloc area.  Each
- * chunk is consisted of nr_cpu_ids units and the first chunk is used
- * for static percpu variables in the kernel image (special boot time
- * alloc/init handling necessary as these areas need to be brought up
- * before allocation services are running).  Unit grows as necessary
- * and all units grow or shrink in unison.  When a chunk is filled up,
- * another chunk is allocated.  ie. in vmalloc area
+ * chunk is consisted of boot-time determined number of units and the
+ * first chunk is used for static percpu variables in the kernel image
+ * (special boot time alloc/init handling necessary as these areas
+ * need to be brought up before allocation services are running).
+ * Unit grows as necessary and all units grow or shrink in unison.
+ * When a chunk is filled up, another chunk is allocated.  ie. in
+ * vmalloc area
  *
  *  c0                           c1                         c2
  *  -------------------          -------------------        ------------
@@ -22,11 +23,13 @@
  *
  * Allocation is done in offset-size areas of single unit space.  Ie,
  * an area of 512 bytes at 6k in c1 occupies 512 bytes at 6k of c1:u0,
- * c1:u1, c1:u2 and c1:u3.  Percpu access can be done by configuring
- * percpu base registers pcpu_unit_size apart.
+ * c1:u1, c1:u2 and c1:u3.  On UMA, units corresponds directly to
+ * cpus.  On NUMA, the mapping can be non-linear and even sparse.
+ * Percpu access can be done by configuring percpu base registers
+ * according to cpu to unit mapping and pcpu_unit_size.
  *
- * There are usually many small percpu allocations many of them as
- * small as 4 bytes.  The allocator organizes chunks into lists
+ * There are usually many small percpu allocations many of them being
+ * as small as 4 bytes.  The allocator organizes chunks into lists
  * according to free size and tries to allocate from the fullest one.
  * Each chunk keeps the maximum contiguous area size hint which is
  * guaranteed to be eqaul to or larger than the maximum contiguous
@@ -43,7 +46,7 @@
  *
  * To use this allocator, arch code should do the followings.
  *
- * - define CONFIG_HAVE_DYNAMIC_PER_CPU_AREA
+ * - drop CONFIG_HAVE_LEGACY_PER_CPU_AREA
  *
  * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
  *   regular address to percpu pointer and back if they need to be
@@ -56,6 +59,7 @@
 #include <linux/bitmap.h>
 #include <linux/bootmem.h>
 #include <linux/list.h>
+#include <linux/log2.h>
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
@@ -94,20 +98,27 @@ struct pcpu_chunk {
         int                     map_alloc;      /* # of map entries allocated */
         int                     *map;           /* allocation map */
         bool                    immutable;      /* no [de]population allowed */
-        struct page             **page;         /* points to page array */
-        struct page             *page_ar[];     /* #cpus * UNIT_PAGES */
+        unsigned long           populated[];    /* populated bitmap */
 };
 
 static int pcpu_unit_pages __read_mostly;
 static int pcpu_unit_size __read_mostly;
+static int pcpu_nr_units __read_mostly;
 static int pcpu_chunk_size __read_mostly;
 static int pcpu_nr_slots __read_mostly;
 static size_t pcpu_chunk_struct_size __read_mostly;
 
+/* cpus with the lowest and highest unit numbers */
+static unsigned int pcpu_first_unit_cpu __read_mostly;
+static unsigned int pcpu_last_unit_cpu __read_mostly;
+
 /* the address of the first chunk which starts with the kernel static area */
 void *pcpu_base_addr __read_mostly;
 EXPORT_SYMBOL_GPL(pcpu_base_addr);
 
+/* cpu -> unit map */
+const int *pcpu_unit_map __read_mostly;
+
 /*
  * The first chunk which always exists.  Note that unlike other
  * chunks, this one can be allocated and mapped in several different
@@ -129,9 +140,9 @@ static int pcpu_reserved_chunk_limit;
  * Synchronization rules.
  *
  * There are two locks - pcpu_alloc_mutex and pcpu_lock.  The former
- * protects allocation/reclaim paths, chunks and chunk->page arrays.
- * The latter is a spinlock and protects the index data structures -
- * chunk slots, chunks and area maps in chunks.
+ * protects allocation/reclaim paths, chunks, populated bitmap and
+ * vmalloc mapping.  The latter is a spinlock and protects the index
+ * data structures - chunk slots, chunks and area maps in chunks.
  *
  * During allocation, pcpu_alloc_mutex is kept locked all the time and
  * pcpu_lock is grabbed and released as necessary.  All actual memory
@@ -178,13 +189,7 @@ static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
 
 static int pcpu_page_idx(unsigned int cpu, int page_idx)
 {
-        return cpu * pcpu_unit_pages + page_idx;
-}
-
-static struct page **pcpu_chunk_pagep(struct pcpu_chunk *chunk,
-                                      unsigned int cpu, int page_idx)
-{
-        return &chunk->page[pcpu_page_idx(cpu, page_idx)];
+        return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
 }
 
 static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
@@ -194,10 +199,13 @@ static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
                 (pcpu_page_idx(cpu, page_idx) << PAGE_SHIFT);
 }
 
-static bool pcpu_chunk_page_occupied(struct pcpu_chunk *chunk,
-                                     int page_idx)
+static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
+                                    unsigned int cpu, int page_idx)
 {
-        return *pcpu_chunk_pagep(chunk, 0, page_idx) != NULL;
+        /* must not be used on pre-mapped chunk */
+        WARN_ON(chunk->immutable);
+
+        return vmalloc_to_page((void *)pcpu_chunk_addr(chunk, cpu, page_idx));
 }
 
 /* set the pointer to a chunk in a page struct */
@@ -212,6 +220,34 @@ static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
         return (struct pcpu_chunk *)page->index;
 }
 
+static void pcpu_next_unpop(struct pcpu_chunk *chunk, int *rs, int *re, int end)
+{
+        *rs = find_next_zero_bit(chunk->populated, end, *rs);
+        *re = find_next_bit(chunk->populated, end, *rs + 1);
+}
+
+static void pcpu_next_pop(struct pcpu_chunk *chunk, int *rs, int *re, int end)
+{
+        *rs = find_next_bit(chunk->populated, end, *rs);
+        *re = find_next_zero_bit(chunk->populated, end, *rs + 1);
+}
+
+/*
+ * (Un)populated page region iterators.  Iterate over (un)populated
+ * page regions betwen @start and @end in @chunk.  @rs and @re should
+ * be integer variables and will be set to start and end page index of
+ * the current region.
+ */
+#define pcpu_for_each_unpop_region(chunk, rs, re, start, end)               \
+        for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \
+             (rs) < (re);                                                   \
+             (rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end)))
+
+#define pcpu_for_each_pop_region(chunk, rs, re, start, end)                 \
+        for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end));   \
+             (rs) < (re);                                                   \
+             (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end)))
+
 /**
  * pcpu_mem_alloc - allocate memory
  * @size: bytes to allocate
@@ -290,13 +326,21 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
         void *first_start = pcpu_first_chunk->vm->addr;
 
         /* is it in the first chunk? */
-        if (addr >= first_start && addr < first_start + pcpu_chunk_size) {
+        if (addr >= first_start && addr < first_start + pcpu_unit_size) {
                 /* is it in the reserved area? */
                 if (addr < first_start + pcpu_reserved_chunk_limit)
                         return pcpu_reserved_chunk;
                 return pcpu_first_chunk;
         }
 
+        /*
+         * The address is relative to unit0 which might be unused and
+         * thus unmapped.  Offset the address to the unit space of the
+         * current processor before looking it up in the vmalloc
+         * space.  Note that any possible cpu id can be used here, so
+         * there's no need to worry about preemption or cpu hotplug.
+         */
+        addr += pcpu_unit_map[smp_processor_id()] * pcpu_unit_size;
         return pcpu_get_page_chunk(vmalloc_to_page(addr));
 }
 
@@ -545,125 +589,327 @@ static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
 }
 
 /**
- * pcpu_unmap - unmap pages out of a pcpu_chunk
+ * pcpu_get_pages_and_bitmap - get temp pages array and bitmap
  * @chunk: chunk of interest
- * @page_start: page index of the first page to unmap
- * @page_end: page index of the last page to unmap + 1
- * @flush_tlb: whether to flush tlb or not
+ * @bitmapp: output parameter for bitmap
+ * @may_alloc: may allocate the array
  *
- * For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
- * If @flush is true, vcache is flushed before unmapping and tlb
- * after.
+ * Returns pointer to array of pointers to struct page and bitmap,
+ * both of which can be indexed with pcpu_page_idx().  The returned
+ * array is cleared to zero and *@bitmapp is copied from
+ * @chunk->populated.  Note that there is only one array and bitmap
+ * and access exclusion is the caller's responsibility.
+ *
+ * CONTEXT:
+ * pcpu_alloc_mutex and does GFP_KERNEL allocation if @may_alloc.
+ * Otherwise, don't care.
+ *
+ * RETURNS:
+ * Pointer to temp pages array on success, NULL on failure.
  */
-static void pcpu_unmap(struct pcpu_chunk *chunk, int page_start, int page_end,
-                       bool flush_tlb)
+static struct page **pcpu_get_pages_and_bitmap(struct pcpu_chunk *chunk,
+                                               unsigned long **bitmapp,
+                                               bool may_alloc)
 {
-        unsigned int last = nr_cpu_ids - 1;
-        unsigned int cpu;
+        static struct page **pages;
+        static unsigned long *bitmap;
+        size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]);
+        size_t bitmap_size = BITS_TO_LONGS(pcpu_unit_pages) *
+                             sizeof(unsigned long);
+
+        if (!pages || !bitmap) {
+                if (may_alloc && !pages)
+                        pages = pcpu_mem_alloc(pages_size);
+                if (may_alloc && !bitmap)
+                        bitmap = pcpu_mem_alloc(bitmap_size);
+                if (!pages || !bitmap)
+                        return NULL;
+        }
 
-        /* unmap must not be done on immutable chunk */
-        WARN_ON(chunk->immutable);
+        memset(pages, 0, pages_size);
+        bitmap_copy(bitmap, chunk->populated, pcpu_unit_pages);
 
-        /*
-         * Each flushing trial can be very expensive, issue flush on
-         * the whole region at once rather than doing it for each cpu.
-         * This could be an overkill but is more scalable.
-         */
-        flush_cache_vunmap(pcpu_chunk_addr(chunk, 0, page_start),
-                           pcpu_chunk_addr(chunk, last, page_end));
+        *bitmapp = bitmap;
+        return pages;
+}
 
-        for_each_possible_cpu(cpu)
-                unmap_kernel_range_noflush(
-                                pcpu_chunk_addr(chunk, cpu, page_start),
-                                (page_end - page_start) << PAGE_SHIFT);
-
-        /* ditto as flush_cache_vunmap() */
-        if (flush_tlb)
-                flush_tlb_kernel_range(pcpu_chunk_addr(chunk, 0, page_start),
-                                       pcpu_chunk_addr(chunk, last, page_end));
+/**
+ * pcpu_free_pages - free pages which were allocated for @chunk
+ * @chunk: chunk pages were allocated for
+ * @pages: array of pages to be freed, indexed by pcpu_page_idx()
+ * @populated: populated bitmap
+ * @page_start: page index of the first page to be freed
+ * @page_end: page index of the last page to be freed + 1
+ *
+ * Free pages [@page_start and @page_end) in @pages for all units.
+ * The pages were allocated for @chunk.
+ */
+static void pcpu_free_pages(struct pcpu_chunk *chunk,
+                            struct page **pages, unsigned long *populated,
+                            int page_start, int page_end)
+{
+        unsigned int cpu;
+        int i;
+
+        for_each_possible_cpu(cpu) {
+                for (i = page_start; i < page_end; i++) {
+                        struct page *page = pages[pcpu_page_idx(cpu, i)];
+
+                        if (page)
+                                __free_page(page);
+                }
+        }
 }
 
 /**
- * pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
- * @chunk: chunk to depopulate
- * @off: offset to the area to depopulate
- * @size: size of the area to depopulate in bytes
- * @flush: whether to flush cache and tlb or not
- *
- * For each cpu, depopulate and unmap pages [@page_start,@page_end)
- * from @chunk.  If @flush is true, vcache is flushed before unmapping
- * and tlb after.
- *
- * CONTEXT:
- * pcpu_alloc_mutex.
+ * pcpu_alloc_pages - allocates pages for @chunk
+ * @chunk: target chunk
+ * @pages: array to put the allocated pages into, indexed by pcpu_page_idx()
+ * @populated: populated bitmap
+ * @page_start: page index of the first page to be allocated
+ * @page_end: page index of the last page to be allocated + 1
+ *
+ * Allocate pages [@page_start,@page_end) into @pages for all units.
+ * The allocation is for @chunk.  Percpu core doesn't care about the
+ * content of @pages and will pass it verbatim to pcpu_map_pages().
  */
-static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size,
-                                  bool flush)
+static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
+                            struct page **pages, unsigned long *populated,
+                            int page_start, int page_end)
 {
-        int page_start = PFN_DOWN(off);
-        int page_end = PFN_UP(off + size);
-        int unmap_start = -1;
-        int uninitialized_var(unmap_end);
+        const gfp_t gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
         unsigned int cpu;
         int i;
 
-        for (i = page_start; i < page_end; i++) {
-                for_each_possible_cpu(cpu) {
-                        struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i);
+        for_each_possible_cpu(cpu) {
+                for (i = page_start; i < page_end; i++) {
+                        struct page **pagep = &pages[pcpu_page_idx(cpu, i)];
+
+                        *pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0);
+                        if (!*pagep) {
+                                pcpu_free_pages(chunk, pages, populated,
+                                                page_start, page_end);
+                                return -ENOMEM;
+                        }
+                }
+        }
+        return 0;
+}
 
-                        if (!*pagep)
-                                continue;
+/**
+ * pcpu_pre_unmap_flush - flush cache prior to unmapping
+ * @chunk: chunk the regions to be flushed belongs to
+ * @page_start: page index of the first page to be flushed
+ * @page_end: page index of the last page to be flushed + 1
+ *
+ * Pages in [@page_start,@page_end) of @chunk are about to be
+ * unmapped.  Flush cache.  As each flushing trial can be very
+ * expensive, issue flush on the whole region at once rather than
+ * doing it for each cpu.  This could be an overkill but is more
+ * scalable.
+ */
+static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
+                                 int page_start, int page_end)
+{
+        flush_cache_vunmap(
+                pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
+                pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
+}
 
-                        __free_page(*pagep);
+static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
+{
+        unmap_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT);
+}
 
-                        /*
-                         * If it's partial depopulation, it might get
-                         * populated or depopulated again.  Mark the
-                         * page gone.
-                         */
-                        *pagep = NULL;
+/**
+ * pcpu_unmap_pages - unmap pages out of a pcpu_chunk
+ * @chunk: chunk of interest
+ * @pages: pages array which can be used to pass information to free
+ * @populated: populated bitmap
+ * @page_start: page index of the first page to unmap
+ * @page_end: page index of the last page to unmap + 1
+ *
+ * For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
+ * Corresponding elements in @pages were cleared by the caller and can
+ * be used to carry information to pcpu_free_pages() which will be
+ * called after all unmaps are finished.  The caller should call
+ * proper pre/post flush functions.
+ */
+static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
+                             struct page **pages, unsigned long *populated,
+                             int page_start, int page_end)
+{
+        unsigned int cpu;
+        int i;
 
-                        unmap_start = unmap_start < 0 ? i : unmap_start;
-                        unmap_end = i + 1;
+        for_each_possible_cpu(cpu) {
+                for (i = page_start; i < page_end; i++) {
+                        struct page *page;
+
+                        page = pcpu_chunk_page(chunk, cpu, i);
+                        WARN_ON(!page);
+                        pages[pcpu_page_idx(cpu, i)] = page;
                 }
+                __pcpu_unmap_pages(pcpu_chunk_addr(chunk, cpu, page_start),
+                                   page_end - page_start);
         }
 
-        if (unmap_start >= 0)
-                pcpu_unmap(chunk, unmap_start, unmap_end, flush);
+        for (i = page_start; i < page_end; i++)
+                __clear_bit(i, populated);
 }
 
 /**
- * pcpu_map - map pages into a pcpu_chunk
+ * pcpu_post_unmap_tlb_flush - flush TLB after unmapping
+ * @chunk: pcpu_chunk the regions to be flushed belong to
+ * @page_start: page index of the first page to be flushed
+ * @page_end: page index of the last page to be flushed + 1
+ *
+ * Pages [@page_start,@page_end) of @chunk have been unmapped.  Flush
+ * TLB for the regions.  This can be skipped if the area is to be
+ * returned to vmalloc as vmalloc will handle TLB flushing lazily.
+ *
+ * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
+ * for the whole region.
+ */
+static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
+                                      int page_start, int page_end)
+{
+        flush_tlb_kernel_range(
+                pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
+                pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
+}
+
+static int __pcpu_map_pages(unsigned long addr, struct page **pages,
+                            int nr_pages)
+{
+        return map_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT,
+                                        PAGE_KERNEL, pages);
+}
+
+/**
+ * pcpu_map_pages - map pages into a pcpu_chunk
  * @chunk: chunk of interest
+ * @pages: pages array containing pages to be mapped
+ * @populated: populated bitmap
  * @page_start: page index of the first page to map
  * @page_end: page index of the last page to map + 1
  *
- * For each cpu, map pages [@page_start,@page_end) into @chunk.
- * vcache is flushed afterwards.
+ * For each cpu, map pages [@page_start,@page_end) into @chunk.  The
+ * caller is responsible for calling pcpu_post_map_flush() after all
+ * mappings are complete.
+ *
+ * This function is responsible for setting corresponding bits in
+ * @chunk->populated bitmap and whatever is necessary for reverse
+ * lookup (addr -> chunk).
  */
-static int pcpu_map(struct pcpu_chunk *chunk, int page_start, int page_end)
+static int pcpu_map_pages(struct pcpu_chunk *chunk,
+                          struct page **pages, unsigned long *populated,
+                          int page_start, int page_end)
 {
-        unsigned int last = nr_cpu_ids - 1;
-        unsigned int cpu;
-        int err;
-
-        /* map must not be done on immutable chunk */
-        WARN_ON(chunk->immutable);
+        unsigned int cpu, tcpu;
+        int i, err;
 
         for_each_possible_cpu(cpu) {
-                err = map_kernel_range_noflush(
-                                pcpu_chunk_addr(chunk, cpu, page_start),
-                                (page_end - page_start) << PAGE_SHIFT,
-                                PAGE_KERNEL,
-                                pcpu_chunk_pagep(chunk, cpu, page_start));
+                err = __pcpu_map_pages(pcpu_chunk_addr(chunk, cpu, page_start),
+                                       &pages[pcpu_page_idx(cpu, page_start)],
+                                       page_end - page_start);
                 if (err < 0)
-                        return err;
+                        goto err;
+        }
+
+        /* mapping successful, link chunk and mark populated */
+        for (i = page_start; i < page_end; i++) {
+                for_each_possible_cpu(cpu)
+                        pcpu_set_page_chunk(pages[pcpu_page_idx(cpu, i)],
+                                            chunk);
+                __set_bit(i, populated);
         }
 
-        /* flush at once, please read comments in pcpu_unmap() */
-        flush_cache_vmap(pcpu_chunk_addr(chunk, 0, page_start),
-                         pcpu_chunk_addr(chunk, last, page_end));
         return 0;
+
+err:
+        for_each_possible_cpu(tcpu) {
+                if (tcpu == cpu)
+                        break;
+                __pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start),
+                                   page_end - page_start);
+        }
+        return err;
+}
+
+/**
+ * pcpu_post_map_flush - flush cache after mapping
+ * @chunk: pcpu_chunk the regions to be flushed belong to
+ * @page_start: page index of the first page to be flushed
+ * @page_end: page index of the last page to be flushed + 1
+ *
+ * Pages [@page_start,@page_end) of @chunk have been mapped.  Flush
+ * cache.
+ *
+ * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
+ * for the whole region.
+ */
+static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
+                                int page_start, int page_end)
+{
+        flush_cache_vmap(
+                pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
+                pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
+}
+
+/**
+ * pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
+ * @chunk: chunk to depopulate
+ * @off: offset to the area to depopulate
+ * @size: size of the area to depopulate in bytes
+ * @flush: whether to flush cache and tlb or not
+ *
+ * For each cpu, depopulate and unmap pages [@page_start,@page_end)
+ * from @chunk.  If @flush is true, vcache is flushed before unmapping
+ * and tlb after.
+ *
+ * CONTEXT:
+ * pcpu_alloc_mutex.
+ */
+static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size)
+{
+        int page_start = PFN_DOWN(off);
+        int page_end = PFN_UP(off + size);
+        struct page **pages;
+        unsigned long *populated;
+        int rs, re;
+
+        /* quick path, check whether it's empty already */
+        pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
+                if (rs == page_start && re == page_end)
+                        return;
+                break;
+        }
+
+        /* immutable chunks can't be depopulated */
+        WARN_ON(chunk->immutable);
+
+        /*
+         * If control reaches here, there must have been at least one
+         * successful population attempt so the temp pages array must
+         * be available now.
+         */
+        pages = pcpu_get_pages_and_bitmap(chunk, &populated, false);
+        BUG_ON(!pages);
+
+        /* unmap and free */
+        pcpu_pre_unmap_flush(chunk, page_start, page_end);
+
+        pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
+                pcpu_unmap_pages(chunk, pages, populated, rs, re);
+
+        /* no need to flush tlb, vmalloc will handle it lazily */
+
+        pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
+                pcpu_free_pages(chunk, pages, populated, rs, re);
+
+        /* commit new bitmap */
+        bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
 }
 
 /**
@@ -680,50 +926,60 @@ static int pcpu_map(struct pcpu_chunk *chunk, int page_start, int page_end)
  */
 static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
 {
-        const gfp_t alloc_mask = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
         int page_start = PFN_DOWN(off);
         int page_end = PFN_UP(off + size);
-        int map_start = -1;
-        int uninitialized_var(map_end);
+        int free_end = page_start, unmap_end = page_start;
+        struct page **pages;
+        unsigned long *populated;
         unsigned int cpu;
-        int i;
+        int rs, re, rc;
 
-        for (i = page_start; i < page_end; i++) {
-                if (pcpu_chunk_page_occupied(chunk, i)) {
-                        if (map_start >= 0) {
-                                if (pcpu_map(chunk, map_start, map_end))
-                                        goto err;
-                                map_start = -1;
-                        }
-                        continue;
-                }
+        /* quick path, check whether all pages are already there */
+        pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end) {
+                if (rs == page_start && re == page_end)
+                        goto clear;
+                break;
+        }
 
-                map_start = map_start < 0 ? i : map_start;
-                map_end = i + 1;
+        /* need to allocate and map pages, this chunk can't be immutable */
+        WARN_ON(chunk->immutable);
 
-                for_each_possible_cpu(cpu) {
-                        struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i);
+        pages = pcpu_get_pages_and_bitmap(chunk, &populated, true);
+        if (!pages)
+                return -ENOMEM;
 
-                        *pagep = alloc_pages_node(cpu_to_node(cpu),
-                                                  alloc_mask, 0);
-                        if (!*pagep)
-                                goto err;
-                        pcpu_set_page_chunk(*pagep, chunk);
-                }
+        /* alloc and map */
+        pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
+                rc = pcpu_alloc_pages(chunk, pages, populated, rs, re);
+                if (rc)
+                        goto err_free;
+                free_end = re;
         }
 
-        if (map_start >= 0 && pcpu_map(chunk, map_start, map_end))
-                goto err;
+        pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
+                rc = pcpu_map_pages(chunk, pages, populated, rs, re);
+                if (rc)
+                        goto err_unmap;
+                unmap_end = re;
+        }
+        pcpu_post_map_flush(chunk, page_start, page_end);
 
+        /* commit new bitmap */
+        bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
+clear:
         for_each_possible_cpu(cpu)
-                memset(chunk->vm->addr + cpu * pcpu_unit_size + off, 0,
-                       size);
-
+                memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
         return 0;
-err:
-        /* likely under heavy memory pressure, give memory back */
-        pcpu_depopulate_chunk(chunk, off, size, true);
-        return -ENOMEM;
+
+err_unmap:
+        pcpu_pre_unmap_flush(chunk, page_start, unmap_end);
+        pcpu_for_each_unpop_region(chunk, rs, re, page_start, unmap_end)
+                pcpu_unmap_pages(chunk, pages, populated, rs, re);
+        pcpu_post_unmap_tlb_flush(chunk, page_start, unmap_end);
+err_free:
+        pcpu_for_each_unpop_region(chunk, rs, re, page_start, free_end)
+                pcpu_free_pages(chunk, pages, populated, rs, re);
+        return rc;
 }
 
 static void free_pcpu_chunk(struct pcpu_chunk *chunk)
@@ -747,7 +1003,6 @@ static struct pcpu_chunk *alloc_pcpu_chunk(void)
         chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0]));
         chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
         chunk->map[chunk->map_used++] = pcpu_unit_size;
-        chunk->page = chunk->page_ar;
 
         chunk->vm = get_vm_area(pcpu_chunk_size, VM_ALLOC);
         if (!chunk->vm) {
@@ -847,6 +1102,7 @@ area_found:
 
         mutex_unlock(&pcpu_alloc_mutex);
 
+        /* return address relative to unit0 */
         return __addr_to_pcpu_ptr(chunk->vm->addr + off);
 
 fail_unlock:
@@ -928,7 +1184,7 @@ static void pcpu_reclaim(struct work_struct *work)
         mutex_unlock(&pcpu_alloc_mutex);
 
         list_for_each_entry_safe(chunk, next, &todo, list) {
-                pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size, false);
+                pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
                 free_pcpu_chunk(chunk);
         }
 }
@@ -976,26 +1232,16 @@ EXPORT_SYMBOL_GPL(free_percpu);
 
 /**
  * pcpu_setup_first_chunk - initialize the first percpu chunk
- * @get_page_fn: callback to fetch page pointer
  * @static_size: the size of static percpu area in bytes
- * @reserved_size: the size of reserved percpu area in bytes
+ * @reserved_size: the size of reserved percpu area in bytes, 0 for none
  * @dyn_size: free size for dynamic allocation in bytes, -1 for auto
- * @unit_size: unit size in bytes, must be multiple of PAGE_SIZE, -1 for auto
- * @base_addr: mapped address, NULL for auto
- * @populate_pte_fn: callback to allocate pagetable, NULL if unnecessary
+ * @unit_size: unit size in bytes, must be multiple of PAGE_SIZE
+ * @base_addr: mapped address
+ * @unit_map: cpu -> unit map, NULL for sequential mapping
  *
  * Initialize the first percpu chunk which contains the kernel static
  * perpcu area.  This function is to be called from arch percpu area
- * setup path.  The first two parameters are mandatory.  The rest are
- * optional.
- *
- * @get_page_fn() should return pointer to percpu page given cpu
- * number and page number.  It should at least return enough pages to
- * cover the static area.  The returned pages for static area should
- * have been initialized with valid data.  If @unit_size is specified,
- * it can also return pages after the static area.  NULL return
- * indicates end of pages for the cpu.  Note that @get_page_fn() must
- * return the same number of pages for all cpus.
+ * setup path.
  *
  * @reserved_size, if non-zero, specifies the amount of bytes to
  * reserve after the static area in the first chunk.  This reserves
@@ -1010,17 +1256,12 @@ EXPORT_SYMBOL_GPL(free_percpu);
  * non-negative value makes percpu leave alone the area beyond
  * @static_size + @reserved_size + @dyn_size.
  *
- * @unit_size, if non-negative, specifies unit size and must be
- * aligned to PAGE_SIZE and equal to or larger than @static_size +
- * @reserved_size + if non-negative, @dyn_size.
- *
- * Non-null @base_addr means that the caller already allocated virtual
- * region for the first chunk and mapped it.  percpu must not mess
- * with the chunk.  Note that @base_addr with 0 @unit_size or non-NULL
- * @populate_pte_fn doesn't make any sense.
+ * @unit_size specifies unit size and must be aligned to PAGE_SIZE and
+ * equal to or larger than @static_size + @reserved_size + if
+ * non-negative, @dyn_size.
  *
- * @populate_pte_fn is used to populate the pagetable.  NULL means the
- * caller already populated the pagetable.
+ * The caller should have mapped the first chunk at @base_addr and
+ * copied static data to each unit.
  *
  * If the first chunk ends up with both reserved and dynamic areas, it
  * is served by two chunks - one to serve the core static and reserved
@@ -1033,47 +1274,83 @@ EXPORT_SYMBOL_GPL(free_percpu);
  * The determined pcpu_unit_size which can be used to initialize
  * percpu access.
  */
-size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
-                                     size_t static_size, size_t reserved_size,
-                                     ssize_t dyn_size, ssize_t unit_size,
-                                     void *base_addr,
-                                     pcpu_populate_pte_fn_t populate_pte_fn)
+size_t __init pcpu_setup_first_chunk(size_t static_size, size_t reserved_size,
+                                     ssize_t dyn_size, size_t unit_size,
+                                     void *base_addr, const int *unit_map)
 {
         static struct vm_struct first_vm;
         static int smap[2], dmap[2];
         size_t size_sum = static_size + reserved_size +
                           (dyn_size >= 0 ? dyn_size : 0);
         struct pcpu_chunk *schunk, *dchunk = NULL;
-        unsigned int cpu;
-        int nr_pages;
-        int err, i;
+        unsigned int cpu, tcpu;
+        int i;
 
-        /* santiy checks */
+        /* sanity checks */
         BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC ||
                      ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC);
         BUG_ON(!static_size);
-        if (unit_size >= 0) {
-                BUG_ON(unit_size < size_sum);
-                BUG_ON(unit_size & ~PAGE_MASK);
-                BUG_ON(unit_size < PCPU_MIN_UNIT_SIZE);
-        } else
-                BUG_ON(base_addr);
-        BUG_ON(base_addr && populate_pte_fn);
-
-        if (unit_size >= 0)
-                pcpu_unit_pages = unit_size >> PAGE_SHIFT;
-        else
-                pcpu_unit_pages = max_t(int, PCPU_MIN_UNIT_SIZE >> PAGE_SHIFT,
-                                        PFN_UP(size_sum));
+        BUG_ON(!base_addr);
+        BUG_ON(unit_size < size_sum);
+        BUG_ON(unit_size & ~PAGE_MASK);
+        BUG_ON(unit_size < PCPU_MIN_UNIT_SIZE);
+
+        /* determine number of units and verify and initialize pcpu_unit_map */
+        if (unit_map) {
+                int first_unit = INT_MAX, last_unit = INT_MIN;
+
+                for_each_possible_cpu(cpu) {
+                        int unit = unit_map[cpu];
+
+                        BUG_ON(unit < 0);
+                        for_each_possible_cpu(tcpu) {
+                                if (tcpu == cpu)
+                                        break;
+                                /* the mapping should be one-to-one */
+                                BUG_ON(unit_map[tcpu] == unit);
+                        }
+
+                        if (unit < first_unit) {
+                                pcpu_first_unit_cpu = cpu;
+                                first_unit = unit;
+                        }
+                        if (unit > last_unit) {
+                                pcpu_last_unit_cpu = cpu;
+                                last_unit = unit;
+                        }
+                }
+                pcpu_nr_units = last_unit + 1;
+                pcpu_unit_map = unit_map;
+        } else {
+                int *identity_map;
+
+                /* #units == #cpus, identity mapped */
+                identity_map = alloc_bootmem(nr_cpu_ids *
+                                             sizeof(identity_map[0]));
 
+                for_each_possible_cpu(cpu)
+                        identity_map[cpu] = cpu;
+
+                pcpu_first_unit_cpu = 0;
+                pcpu_last_unit_cpu = pcpu_nr_units - 1;
+                pcpu_nr_units = nr_cpu_ids;
+                pcpu_unit_map = identity_map;
+        }
+
+        /* determine basic parameters */
+        pcpu_unit_pages = unit_size >> PAGE_SHIFT;
         pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
-        pcpu_chunk_size = nr_cpu_ids * pcpu_unit_size;
-        pcpu_chunk_struct_size = sizeof(struct pcpu_chunk)
-                + nr_cpu_ids * pcpu_unit_pages * sizeof(struct page *);
+        pcpu_chunk_size = pcpu_nr_units * pcpu_unit_size;
+        pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
+                BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
 
         if (dyn_size < 0)
                 dyn_size = pcpu_unit_size - static_size - reserved_size;
 
+        first_vm.flags = VM_ALLOC;
+        first_vm.size = pcpu_chunk_size;
+        first_vm.addr = base_addr;
+
         /*
          * Allocate chunk slots.  The additional last slot is for
          * empty chunks.
@@ -1095,7 +1372,8 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
         schunk->vm = &first_vm;
         schunk->map = smap;
         schunk->map_alloc = ARRAY_SIZE(smap);
-        schunk->page = schunk->page_ar;
+        schunk->immutable = true;
+        bitmap_fill(schunk->populated, pcpu_unit_pages);
 
         if (reserved_size) {
                 schunk->free_size = reserved_size;
@@ -1113,93 +1391,39 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
 
         /* init dynamic chunk if necessary */
         if (dyn_size) {
-                dchunk = alloc_bootmem(sizeof(struct pcpu_chunk));
+                dchunk = alloc_bootmem(pcpu_chunk_struct_size);
                 INIT_LIST_HEAD(&dchunk->list);
                 dchunk->vm = &first_vm;
                 dchunk->map = dmap;
                 dchunk->map_alloc = ARRAY_SIZE(dmap);
-                dchunk->page = schunk->page_ar; /* share page map with schunk */
+                dchunk->immutable = true;
+                bitmap_fill(dchunk->populated, pcpu_unit_pages);
 
                 dchunk->contig_hint = dchunk->free_size = dyn_size;
                 dchunk->map[dchunk->map_used++] = -pcpu_reserved_chunk_limit;
                 dchunk->map[dchunk->map_used++] = dchunk->free_size;
         }
 
-        /* allocate vm address */
-        first_vm.flags = VM_ALLOC;
-        first_vm.size = pcpu_chunk_size;
-
-        if (!base_addr)
-                vm_area_register_early(&first_vm, PAGE_SIZE);
-        else {
-                /*
-                 * Pages already mapped.  No need to remap into
-                 * vmalloc area.  In this case the first chunks can't
-                 * be mapped or unmapped by percpu and are marked
-                 * immutable.
-                 */
-                first_vm.addr = base_addr;
-                schunk->immutable = true;
-                if (dchunk)
-                        dchunk->immutable = true;
-        }
-
-        /* assign pages */
-        nr_pages = -1;
-        for_each_possible_cpu(cpu) {
-                for (i = 0; i < pcpu_unit_pages; i++) {
-                        struct page *page = get_page_fn(cpu, i);
-
-                        if (!page)
-                                break;
-                        *pcpu_chunk_pagep(schunk, cpu, i) = page;
-                }
-
-                BUG_ON(i < PFN_UP(static_size));
-
-                if (nr_pages < 0)
-                        nr_pages = i;
-                else
-                        BUG_ON(nr_pages != i);
-        }
-
-        /* map them */
-        if (populate_pte_fn) {
-                for_each_possible_cpu(cpu)
-                        for (i = 0; i < nr_pages; i++)
-                                populate_pte_fn(pcpu_chunk_addr(schunk,
-                                                                cpu, i));
-
-                err = pcpu_map(schunk, 0, nr_pages);
-                if (err)
-                        panic("failed to setup static percpu area, err=%d\n",
-                              err);
-        }
-
         /* link the first chunk in */
         pcpu_first_chunk = dchunk ?: schunk;
         pcpu_chunk_relocate(pcpu_first_chunk, -1);
 
         /* we're done */
-        pcpu_base_addr = (void *)pcpu_chunk_addr(schunk, 0, 0);
+        pcpu_base_addr = schunk->vm->addr;
         return pcpu_unit_size;
 }
 
-/*
- * Embedding first chunk setup helper.
- */
-static void *pcpue_ptr __initdata;
-static size_t pcpue_size __initdata;
-static size_t pcpue_unit_size __initdata;
-
-static struct page * __init pcpue_get_page(unsigned int cpu, int pageno)
+static size_t pcpu_calc_fc_sizes(size_t static_size, size_t reserved_size,
+                                 ssize_t *dyn_sizep)
 {
-        size_t off = (size_t)pageno << PAGE_SHIFT;
+        size_t size_sum;
 
-        if (off >= pcpue_size)
-                return NULL;
+        size_sum = PFN_ALIGN(static_size + reserved_size +
+                             (*dyn_sizep >= 0 ? *dyn_sizep : 0));
+        if (*dyn_sizep != 0)
+                *dyn_sizep = size_sum - static_size - reserved_size;
 
-        return virt_to_page(pcpue_ptr + cpu * pcpue_unit_size + off);
+        return size_sum;
 }
 
 /**
@@ -1207,7 +1431,6 @@ static struct page * __init pcpue_get_page(unsigned int cpu, int pageno)
  * @static_size: the size of static percpu area in bytes
  * @reserved_size: the size of reserved percpu area in bytes
  * @dyn_size: free size for dynamic allocation in bytes, -1 for auto
- * @unit_size: unit size in bytes, must be multiple of PAGE_SIZE, -1 for auto
  *
  * This is a helper to ease setting up embedded first percpu chunk and
  * can be called where pcpu_setup_first_chunk() is expected.
@@ -1219,9 +1442,9 @@ static struct page * __init pcpue_get_page(unsigned int cpu, int pageno)
  * page size.
  *
  * When @dyn_size is positive, dynamic area might be larger than
- * specified to fill page alignment.  Also, when @dyn_size is auto,
- * @dyn_size does not fill the whole first chunk but only what's
- * necessary for page alignment after static and reserved areas.
+ * specified to fill page alignment.  When @dyn_size is auto,
+ * @dyn_size is just big enough to fill page alignment after static
+ * and reserved areas.
  *
  * If the needed size is smaller than the minimum or specified unit
  * size, the leftover is returned to the bootmem allocator.
@@ -1231,28 +1454,21 @@ static struct page * __init pcpue_get_page(unsigned int cpu, int pageno)
  * percpu access on success, -errno on failure.
  */
 ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size,
-                                      ssize_t dyn_size, ssize_t unit_size)
+                                      ssize_t dyn_size)
 {
-        size_t chunk_size;
+        size_t size_sum, unit_size, chunk_size;
+        void *base;
         unsigned int cpu;
 
         /* determine parameters and allocate */
-        pcpue_size = PFN_ALIGN(static_size + reserved_size +
-                               (dyn_size >= 0 ? dyn_size : 0));
-        if (dyn_size != 0)
-                dyn_size = pcpue_size - static_size - reserved_size;
-
-        if (unit_size >= 0) {
-                BUG_ON(unit_size < pcpue_size);
-                pcpue_unit_size = unit_size;
-        } else
-                pcpue_unit_size = max_t(size_t, pcpue_size, PCPU_MIN_UNIT_SIZE);
-
-        chunk_size = pcpue_unit_size * nr_cpu_ids;
-
-        pcpue_ptr = __alloc_bootmem_nopanic(chunk_size, PAGE_SIZE,
-                                            __pa(MAX_DMA_ADDRESS));
-        if (!pcpue_ptr) {
+        size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size);
+
+        unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
+        chunk_size = unit_size * nr_cpu_ids;
+
+        base = __alloc_bootmem_nopanic(chunk_size, PAGE_SIZE,
+                                       __pa(MAX_DMA_ADDRESS));
+        if (!base) {
                 pr_warning("PERCPU: failed to allocate %zu bytes for "
                            "embedding\n", chunk_size);
                 return -ENOMEM;
@@ -1260,21 +1476,543 @@ ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size,
 
         /* return the leftover and copy */
         for (cpu = 0; cpu < nr_cpu_ids; cpu++) {
-                void *ptr = pcpue_ptr + cpu * pcpue_unit_size;
+                void *ptr = base + cpu * unit_size;
 
                 if (cpu_possible(cpu)) {
-                        free_bootmem(__pa(ptr + pcpue_size),
-                                     pcpue_unit_size - pcpue_size);
+                        free_bootmem(__pa(ptr + size_sum),
+                                     unit_size - size_sum);
                         memcpy(ptr, __per_cpu_load, static_size);
                 } else
-                        free_bootmem(__pa(ptr), pcpue_unit_size);
+                        free_bootmem(__pa(ptr), unit_size);
         }
 
         /* we're ready, commit */
         pr_info("PERCPU: Embedded %zu pages at %p, static data %zu bytes\n",
-                pcpue_size >> PAGE_SHIFT, pcpue_ptr, static_size);
+                size_sum >> PAGE_SHIFT, base, static_size);
+
+        return pcpu_setup_first_chunk(static_size, reserved_size, dyn_size,
+                                      unit_size, base, NULL);
+}
+
+/**
+ * pcpu_4k_first_chunk - map the first chunk using PAGE_SIZE pages
+ * @static_size: the size of static percpu area in bytes
+ * @reserved_size: the size of reserved percpu area in bytes
+ * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
+ * @free_fn: funtion to free percpu page, always called with PAGE_SIZE
+ * @populate_pte_fn: function to populate pte
+ *
+ * This is a helper to ease setting up embedded first percpu chunk and
+ * can be called where pcpu_setup_first_chunk() is expected.
+ *
+ * This is the basic allocator.  Static percpu area is allocated
+ * page-by-page into vmalloc area.
+ *
+ * RETURNS:
+ * The determined pcpu_unit_size which can be used to initialize
+ * percpu access on success, -errno on failure.
+ */
+ssize_t __init pcpu_4k_first_chunk(size_t static_size, size_t reserved_size,
+                                   pcpu_fc_alloc_fn_t alloc_fn,
+                                   pcpu_fc_free_fn_t free_fn,
+                                   pcpu_fc_populate_pte_fn_t populate_pte_fn)
+{
+        static struct vm_struct vm;
+        int unit_pages;
+        size_t pages_size;
+        struct page **pages;
+        unsigned int cpu;
+        int i, j;
+        ssize_t ret;
+
+        unit_pages = PFN_UP(max_t(size_t, static_size + reserved_size,
+                                  PCPU_MIN_UNIT_SIZE));
+
+        /* unaligned allocations can't be freed, round up to page size */
+        pages_size = PFN_ALIGN(unit_pages * nr_cpu_ids * sizeof(pages[0]));
+        pages = alloc_bootmem(pages_size);
+
+        /* allocate pages */
+        j = 0;
+        for_each_possible_cpu(cpu)
+                for (i = 0; i < unit_pages; i++) {
+                        void *ptr;
+
+                        ptr = alloc_fn(cpu, PAGE_SIZE);
+                        if (!ptr) {
+                                pr_warning("PERCPU: failed to allocate "
+                                           "4k page for cpu%u\n", cpu);
+                                goto enomem;
+                        }
+                        pages[j++] = virt_to_page(ptr);
+                }
+
+        /* allocate vm area, map the pages and copy static data */
+        vm.flags = VM_ALLOC;
+        vm.size = nr_cpu_ids * unit_pages << PAGE_SHIFT;
+        vm_area_register_early(&vm, PAGE_SIZE);
+
+        for_each_possible_cpu(cpu) {
+                unsigned long unit_addr = (unsigned long)vm.addr +
+                        (cpu * unit_pages << PAGE_SHIFT);
+
+                for (i = 0; i < unit_pages; i++)
+                        populate_pte_fn(unit_addr + (i << PAGE_SHIFT));
+
+                /* pte already populated, the following shouldn't fail */
+                ret = __pcpu_map_pages(unit_addr, &pages[cpu * unit_pages],
+                                       unit_pages);
+                if (ret < 0)
+                        panic("failed to map percpu area, err=%zd\n", ret);
+
+                /*
+                 * FIXME: Archs with virtual cache should flush local
+                 * cache for the linear mapping here - something
+                 * equivalent to flush_cache_vmap() on the local cpu.
+                 * flush_cache_vmap() can't be used as most supporting
+                 * data structures are not set up yet.
+                 */
+
+                /* copy static data */
+                memcpy((void *)unit_addr, __per_cpu_load, static_size);
+        }
+
+        /* we're ready, commit */
+        pr_info("PERCPU: %d 4k pages per cpu, static data %zu bytes\n",
+                unit_pages, static_size);
+
+        ret = pcpu_setup_first_chunk(static_size, reserved_size, -1,
+                                     unit_pages << PAGE_SHIFT, vm.addr, NULL);
+        goto out_free_ar;
+
+enomem:
+        while (--j >= 0)
+                free_fn(page_address(pages[j]), PAGE_SIZE);
+        ret = -ENOMEM;
+out_free_ar:
+        free_bootmem(__pa(pages), pages_size);
+        return ret;
+}
+
+/*
+ * Large page remapping first chunk setup helper
+ */
+#ifdef CONFIG_NEED_MULTIPLE_NODES
+
+/**
+ * pcpu_lpage_build_unit_map - build unit_map for large page remapping
+ * @static_size: the size of static percpu area in bytes
+ * @reserved_size: the size of reserved percpu area in bytes
+ * @dyn_sizep: in/out parameter for dynamic size, -1 for auto
+ * @unit_sizep: out parameter for unit size
+ * @unit_map: unit_map to be filled
+ * @cpu_distance_fn: callback to determine distance between cpus
+ *
+ * This function builds cpu -> unit map and determine other parameters
+ * considering needed percpu size, large page size and distances
+ * between CPUs in NUMA.
+ *
+ * CPUs which are of LOCAL_DISTANCE both ways are grouped together and
+ * may share units in the same large page.  The returned configuration
+ * is guaranteed to have CPUs on different nodes on different large
+ * pages and >=75% usage of allocated virtual address space.
+ *
+ * RETURNS:
+ * On success, fills in @unit_map, sets *@dyn_sizep, *@unit_sizep and
+ * returns the number of units to be allocated.  -errno on failure.
+ */
+int __init pcpu_lpage_build_unit_map(size_t static_size, size_t reserved_size,
+                                     ssize_t *dyn_sizep, size_t *unit_sizep,
+                                     size_t lpage_size, int *unit_map,
+                                     pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
+{
+        static int group_map[NR_CPUS] __initdata;
+        static int group_cnt[NR_CPUS] __initdata;
+        int group_cnt_max = 0;
+        size_t size_sum, min_unit_size, alloc_size;
+        int upa, max_upa, uninitialized_var(best_upa);  /* units_per_alloc */
+        int last_allocs;
+        unsigned int cpu, tcpu;
+        int group, unit;
+
+        /*
+         * Determine min_unit_size, alloc_size and max_upa such that
+         * alloc_size is multiple of lpage_size and is the smallest
+         * which can accomodate 4k aligned segments which are equal to
+         * or larger than min_unit_size.
+         */
+        size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, dyn_sizep);
+        min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
+
+        alloc_size = roundup(min_unit_size, lpage_size);
+        upa = alloc_size / min_unit_size;
+        while (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
+                upa--;
+        max_upa = upa;
+
+        /* group cpus according to their proximity */
+        for_each_possible_cpu(cpu) {
+                group = 0;
+        next_group:
+                for_each_possible_cpu(tcpu) {
+                        if (cpu == tcpu)
+                                break;
+                        if (group_map[tcpu] == group &&
+                            (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE ||
+                             cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) {
+                                group++;
+                                goto next_group;
+                        }
+                }
+                group_map[cpu] = group;
+                group_cnt[group]++;
+                group_cnt_max = max(group_cnt_max, group_cnt[group]);
+        }
+
+        /*
+         * Expand unit size until address space usage goes over 75%
+         * and then as much as possible without using more address
+         * space.
+         */
+        last_allocs = INT_MAX;
+        for (upa = max_upa; upa; upa--) {
+                int allocs = 0, wasted = 0;
+
+                if (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
+                        continue;
+
+                for (group = 0; group_cnt[group]; group++) {
+                        int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
+                        allocs += this_allocs;
+                        wasted += this_allocs * upa - group_cnt[group];
+                }
+
+                /*
+                 * Don't accept if wastage is over 25%.  The
+                 * greater-than comparison ensures upa==1 always
+                 * passes the following check.
+                 */
+                if (wasted > num_possible_cpus() / 3)
+                        continue;
+
+                /* and then don't consume more memory */
+                if (allocs > last_allocs)
+                        break;
+                last_allocs = allocs;
+                best_upa = upa;
+        }
+        *unit_sizep = alloc_size / best_upa;
 
-        return pcpu_setup_first_chunk(pcpue_get_page, static_size,
-                                      reserved_size, dyn_size,
-                                      pcpue_unit_size, pcpue_ptr, NULL);
+        /* assign units to cpus accordingly */
+        unit = 0;
+        for (group = 0; group_cnt[group]; group++) {
+                for_each_possible_cpu(cpu)
+                        if (group_map[cpu] == group)
+                                unit_map[cpu] = unit++;
+                unit = roundup(unit, best_upa);
+        }
+
+        return unit;    /* unit contains aligned number of units */
+}
+
+struct pcpul_ent {
+        void            *ptr;
+        void            *map_addr;
+};
+
+static size_t pcpul_size;
+static size_t pcpul_lpage_size;
+static int pcpul_nr_lpages;
+static struct pcpul_ent *pcpul_map;
+
+static bool __init pcpul_unit_to_cpu(int unit, const int *unit_map,
+                                     unsigned int *cpup)
+{
+        unsigned int cpu;
+
+        for_each_possible_cpu(cpu)
+                if (unit_map[cpu] == unit) {
+                        if (cpup)
+                                *cpup = cpu;
+                        return true;
+                }
+
+        return false;
+}
+
+static void __init pcpul_lpage_dump_cfg(const char *lvl, size_t static_size,
+                                        size_t reserved_size, size_t dyn_size,
+                                        size_t unit_size, size_t lpage_size,
+                                        const int *unit_map, int nr_units)
+{
+        int width = 1, v = nr_units;
+        char empty_str[] = "--------";
+        int upl, lpl;   /* units per lpage, lpage per line */
+        unsigned int cpu;
+        int lpage, unit;
+
+        while (v /= 10)
+                width++;
+        empty_str[min_t(int, width, sizeof(empty_str) - 1)] = '\0';
+
+        upl = max_t(int, lpage_size / unit_size, 1);
+        lpl = rounddown_pow_of_two(max_t(int, 60 / (upl * (width + 1) + 2), 1));
+
+        printk("%spcpu-lpage: sta/res/dyn=%zu/%zu/%zu unit=%zu lpage=%zu", lvl,
+               static_size, reserved_size, dyn_size, unit_size, lpage_size);
+
+        for (lpage = 0, unit = 0; unit < nr_units; unit++) {
+                if (!(unit % upl)) {
+                        if (!(lpage++ % lpl)) {
+                                printk("\n");
+                                printk("%spcpu-lpage: ", lvl);
+                        } else
+                                printk("| ");
+                }
+                if (pcpul_unit_to_cpu(unit, unit_map, &cpu))
+                        printk("%0*d ", width, cpu);
+                else
+                        printk("%s ", empty_str);
+        }
+        printk("\n");
+}
+
+/**
+ * pcpu_lpage_first_chunk - remap the first percpu chunk using large page
+ * @static_size: the size of static percpu area in bytes
+ * @reserved_size: the size of reserved percpu area in bytes
+ * @dyn_size: free size for dynamic allocation in bytes
+ * @unit_size: unit size in bytes
+ * @lpage_size: the size of a large page
+ * @unit_map: cpu -> unit mapping
+ * @nr_units: the number of units
+ * @alloc_fn: function to allocate percpu lpage, always called with lpage_size
+ * @free_fn: function to free percpu memory, @size <= lpage_size
+ * @map_fn: function to map percpu lpage, always called with lpage_size
+ *
+ * This allocator uses large page to build and map the first chunk.
+ * Unlike other helpers, the caller should always specify @dyn_size
+ * and @unit_size.  These parameters along with @unit_map and
+ * @nr_units can be determined using pcpu_lpage_build_unit_map().
+ * This two stage initialization is to allow arch code to evaluate the
+ * parameters before committing to it.
+ *
+ * Large pages are allocated as directed by @unit_map and other
+ * parameters and mapped to vmalloc space.  Unused holes are returned
+ * to the page allocator.  Note that these holes end up being actively
+ * mapped twice - once to the physical mapping and to the vmalloc area
+ * for the first percpu chunk.  Depending on architecture, this might
+ * cause problem when changing page attributes of the returned area.
+ * These double mapped areas can be detected using
+ * pcpu_lpage_remapped().
+ *
+ * RETURNS:
+ * The determined pcpu_unit_size which can be used to initialize
+ * percpu access on success, -errno on failure.
+ */
+ssize_t __init pcpu_lpage_first_chunk(size_t static_size, size_t reserved_size,
+                                      size_t dyn_size, size_t unit_size,
+                                      size_t lpage_size, const int *unit_map,
+                                      int nr_units,
+                                      pcpu_fc_alloc_fn_t alloc_fn,
+                                      pcpu_fc_free_fn_t free_fn,
+                                      pcpu_fc_map_fn_t map_fn)
+{
+        static struct vm_struct vm;
+        size_t chunk_size = unit_size * nr_units;
+        size_t map_size;
+        unsigned int cpu;
+        ssize_t ret;
+        int i, j, unit;
+
+        pcpul_lpage_dump_cfg(KERN_DEBUG, static_size, reserved_size, dyn_size,
+                             unit_size, lpage_size, unit_map, nr_units);
+
+        BUG_ON(chunk_size % lpage_size);
+
+        pcpul_size = static_size + reserved_size + dyn_size;
+        pcpul_lpage_size = lpage_size;
+        pcpul_nr_lpages = chunk_size / lpage_size;
+
+        /* allocate pointer array and alloc large pages */
+        map_size = pcpul_nr_lpages * sizeof(pcpul_map[0]);
+        pcpul_map = alloc_bootmem(map_size);
+
+        /* allocate all pages */
+        for (i = 0; i < pcpul_nr_lpages; i++) {
+                size_t offset = i * lpage_size;
+                int first_unit = offset / unit_size;
+                int last_unit = (offset + lpage_size - 1) / unit_size;
+                void *ptr;
+
+                /* find out which cpu is mapped to this unit */
+                for (unit = first_unit; unit <= last_unit; unit++)
+                        if (pcpul_unit_to_cpu(unit, unit_map, &cpu))
+                                goto found;
+                continue;
+        found:
+                ptr = alloc_fn(cpu, lpage_size);
+                if (!ptr) {
+                        pr_warning("PERCPU: failed to allocate large page "
+                                   "for cpu%u\n", cpu);
+                        goto enomem;
+                }
+
+                pcpul_map[i].ptr = ptr;
+        }
+
+        /* return unused holes */
+        for (unit = 0; unit < nr_units; unit++) {
+                size_t start = unit * unit_size;
+                size_t end = start + unit_size;
+                size_t off, next;
+
+                /* don't free used part of occupied unit */
+                if (pcpul_unit_to_cpu(unit, unit_map, NULL))
+                        start += pcpul_size;
+
+                /* unit can span more than one page, punch the holes */
+                for (off = start; off < end; off = next) {
+                        void *ptr = pcpul_map[off / lpage_size].ptr;
+                        next = min(roundup(off + 1, lpage_size), end);
+                        if (ptr)
+                                free_fn(ptr + off % lpage_size, next - off);
+                }
+        }
+
+        /* allocate address, map and copy */
+        vm.flags = VM_ALLOC;
+        vm.size = chunk_size;
+        vm_area_register_early(&vm, unit_size);
+
+        for (i = 0; i < pcpul_nr_lpages; i++) {
+                if (!pcpul_map[i].ptr)
+                        continue;
+                pcpul_map[i].map_addr = vm.addr + i * lpage_size;
+                map_fn(pcpul_map[i].ptr, lpage_size, pcpul_map[i].map_addr);
+        }
+
+        for_each_possible_cpu(cpu)
+                memcpy(vm.addr + unit_map[cpu] * unit_size, __per_cpu_load,
+                       static_size);
+
+        /* we're ready, commit */
+        pr_info("PERCPU: Remapped at %p with large pages, static data "
+                "%zu bytes\n", vm.addr, static_size);
+
+        ret = pcpu_setup_first_chunk(static_size, reserved_size, dyn_size,
+                                     unit_size, vm.addr, unit_map);
+
+        /*
+         * Sort pcpul_map array for pcpu_lpage_remapped().  Unmapped
+         * lpages are pushed to the end and trimmed.
+         */
+        for (i = 0; i < pcpul_nr_lpages - 1; i++)
+                for (j = i + 1; j < pcpul_nr_lpages; j++) {
+                        struct pcpul_ent tmp;
+
+                        if (!pcpul_map[j].ptr)
+                                continue;
+                        if (pcpul_map[i].ptr &&
+                            pcpul_map[i].ptr < pcpul_map[j].ptr)
+                                continue;
+
+                        tmp = pcpul_map[i];
+                        pcpul_map[i] = pcpul_map[j];
+                        pcpul_map[j] = tmp;
+                }
+
+        while (pcpul_nr_lpages && !pcpul_map[pcpul_nr_lpages - 1].ptr)
+                pcpul_nr_lpages--;
+
+        return ret;
+
+enomem:
+        for (i = 0; i < pcpul_nr_lpages; i++)
+                if (pcpul_map[i].ptr)
+                        free_fn(pcpul_map[i].ptr, lpage_size);
+        free_bootmem(__pa(pcpul_map), map_size);
+        return -ENOMEM;
+}
+
+/**
+ * pcpu_lpage_remapped - determine whether a kaddr is in pcpul recycled area
+ * @kaddr: the kernel address in question
+ *
+ * Determine whether @kaddr falls in the pcpul recycled area.  This is
+ * used by pageattr to detect VM aliases and break up the pcpu large
+ * page mapping such that the same physical page is not mapped under
+ * different attributes.
+ *
+ * The recycled area is always at the tail of a partially used large
+ * page.
+ *
+ * RETURNS:
+ * Address of corresponding remapped pcpu address if match is found;
+ * otherwise, NULL.
+ */
+void *pcpu_lpage_remapped(void *kaddr)
+{
+        unsigned long lpage_mask = pcpul_lpage_size - 1;
+        void *lpage_addr = (void *)((unsigned long)kaddr & ~lpage_mask);
+        unsigned long offset = (unsigned long)kaddr & lpage_mask;
+        int left = 0, right = pcpul_nr_lpages - 1;
+        int pos;
+
+        /* pcpul in use at all? */
+        if (!pcpul_map)
+                return NULL;
+
+        /* okay, perform binary search */
+        while (left <= right) {
+                pos = (left + right) / 2;
+
+                if (pcpul_map[pos].ptr < lpage_addr)
+                        left = pos + 1;
+                else if (pcpul_map[pos].ptr > lpage_addr)
+                        right = pos - 1;
+                else
+                        return pcpul_map[pos].map_addr + offset;
+        }
+
+        return NULL;
+}
+#endif
+
+/*
+ * Generic percpu area setup.
+ *
+ * The embedding helper is used because its behavior closely resembles
+ * the original non-dynamic generic percpu area setup.  This is
+ * important because many archs have addressing restrictions and might
+ * fail if the percpu area is located far away from the previous
+ * location.  As an added bonus, in non-NUMA cases, embedding is
+ * generally a good idea TLB-wise because percpu area can piggy back
+ * 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);
+
+void __init setup_per_cpu_areas(void)
+{
+        size_t static_size = __per_cpu_end - __per_cpu_start;
+        ssize_t unit_size;
+        unsigned long delta;
+        unsigned int cpu;
+
+        /*
+         * Always reserve area for module percpu variables.  That's
+         * what the legacy allocator did.
+         */
+        unit_size = pcpu_embed_first_chunk(static_size, PERCPU_MODULE_RESERVE,
+                                           PERCPU_DYNAMIC_RESERVE);
+        if (unit_size < 0)
+                panic("Failed to initialized percpu areas.");
+
+        delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
+        for_each_possible_cpu(cpu)
+                __per_cpu_offset[cpu] = delta + cpu * unit_size;
 }
+#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */