1 files changed, 384 insertions, 220 deletions

diff --git a/mm/percpu.c b/mm/percpu.c
index 639fce4d2caf..21756814d99f 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -94,8 +94,7 @@ 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;
@@ -129,9 +128,9 @@ 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
@@ -188,16 +187,13 @@ static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
                 (pcpu_page_idx(cpu, page_idx) << PAGE_SHIFT);
 }
 
-static struct page **pcpu_chunk_pagep(struct pcpu_chunk *chunk,
-                                      unsigned int cpu, int page_idx)
+static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
+                                    unsigned int cpu, int page_idx)
 {
-        return &chunk->page[pcpu_page_idx(cpu, page_idx)];
-}
+        /* must not be used on pre-mapped chunk */
+        WARN_ON(chunk->immutable);
 
-static bool pcpu_chunk_page_occupied(struct pcpu_chunk *chunk,
-                                     int page_idx)
-{
-        return *pcpu_chunk_pagep(chunk, 0, page_idx) != NULL;
+        return vmalloc_to_page((void *)pcpu_chunk_addr(chunk, cpu, page_idx));
 }
 
 /* set the pointer to a chunk in a page struct */
@@ -212,6 +208,34 @@ 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
@@ -545,42 +569,197 @@ 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
+ * @bitmapp: output parameter for bitmap
+ * @may_alloc: may allocate the array
+ *
+ * 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 struct page **pcpu_get_pages_and_bitmap(struct pcpu_chunk *chunk,
+                                               unsigned long **bitmapp,
+                                               bool may_alloc)
+{
+        static struct page **pages;
+        static unsigned long *bitmap;
+        size_t pages_size = num_possible_cpus() * 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;
+        }
+
+        memset(pages, 0, pages_size);
+        bitmap_copy(bitmap, chunk->populated, pcpu_unit_pages);
+
+        *bitmapp = bitmap;
+        return pages;
+}
+
+/**
+ * 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_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 int pcpu_alloc_pages(struct pcpu_chunk *chunk,
+                            struct page **pages, unsigned long *populated,
+                            int page_start, int page_end)
+{
+        const gfp_t gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
+        unsigned int cpu;
+        int 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;
+}
+
+/**
+ * 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)
+{
+        unsigned int last = num_possible_cpus() - 1;
+
+        flush_cache_vunmap(pcpu_chunk_addr(chunk, 0, page_start),
+                           pcpu_chunk_addr(chunk, last, page_end));
+}
+
+static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
+{
+        unmap_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT);
+}
+
+/**
+ * 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
- * @flush_tlb: whether to flush tlb or not
  *
  * For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
- * If @flush is true, vcache is flushed before unmapping and tlb
- * after.
+ * 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(struct pcpu_chunk *chunk, int page_start, int page_end,
-                       bool flush_tlb)
+static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
+                             struct page **pages, unsigned long *populated,
+                             int page_start, int page_end)
 {
-        unsigned int last = num_possible_cpus() - 1;
         unsigned int cpu;
+        int i;
 
-        /* unmap must not be done on immutable chunk */
-        WARN_ON(chunk->immutable);
+        for_each_possible_cpu(cpu) {
+                for (i = page_start; i < page_end; i++) {
+                        struct page *page;
 
-        /*
-         * 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));
+                        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);
+        }
 
-        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));
+        for (i = page_start; i < page_end; i++)
+                __clear_bit(i, populated);
+}
+
+/**
+ * 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)
+{
+        unsigned int last = num_possible_cpus() - 1;
+
+        flush_tlb_kernel_range(pcpu_chunk_addr(chunk, 0, page_start),
+                               pcpu_chunk_addr(chunk, last, page_end));
 }
 
 static int __pcpu_map_pages(unsigned long addr, struct page **pages,
@@ -591,35 +770,76 @@ static int __pcpu_map_pages(unsigned long addr, struct page **pages,
 }
 
 /**
- * pcpu_map - map pages into a pcpu_chunk
+ * 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 = num_possible_cpus() - 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 = __pcpu_map_pages(pcpu_chunk_addr(chunk, cpu, page_start),
-                                       pcpu_chunk_pagep(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);
+        }
+
+        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)
+{
+        unsigned int last = num_possible_cpus() - 1;
+
         /* 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;
 }
 
 /**
@@ -636,39 +856,45 @@ static int pcpu_map(struct pcpu_chunk *chunk, int page_start, int page_end)
  * CONTEXT:
  * pcpu_alloc_mutex.
  */
-static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size,
-                                  bool flush)
+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);
-        int unmap_start = -1;
-        int uninitialized_var(unmap_end);
-        unsigned int cpu;
-        int i;
+        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;
+        }
 
-        for (i = page_start; i < page_end; i++) {
-                for_each_possible_cpu(cpu) {
-                        struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i);
+        /* immutable chunks can't be depopulated */
+        WARN_ON(chunk->immutable);
 
-                        if (!*pagep)
-                                continue;
+        /*
+         * 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);
 
-                        __free_page(*pagep);
+        /* unmap and free */
+        pcpu_pre_unmap_flush(chunk, page_start, page_end);
 
-                        /*
-                         * If it's partial depopulation, it might get
-                         * populated or depopulated again.  Mark the
-                         * page gone.
-                         */
-                        *pagep = NULL;
+        pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
+                pcpu_unmap_pages(chunk, pages, populated, rs, re);
 
-                        unmap_start = unmap_start < 0 ? i : unmap_start;
-                        unmap_end = i + 1;
-                }
-        }
+        /* 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);
 
-        if (unmap_start >= 0)
-                pcpu_unmap(chunk, unmap_start, unmap_end, flush);
+        /* commit new bitmap */
+        bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
 }
 
 /**
@@ -685,50 +911,61 @@ static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size,
  */
 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);
-
         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)
@@ -752,7 +989,6 @@ 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, GFP_KERNEL);
         if (!chunk->vm) {
@@ -933,7 +1169,7 @@ 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);
         }
 }
@@ -981,7 +1217,6 @@ 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, 0 for none
  * @dyn_size: free size for dynamic allocation in bytes, -1 for auto
@@ -992,14 +1227,6 @@ EXPORT_SYMBOL_GPL(free_percpu);
  * perpcu area.  This function is to be called from arch percpu area
  * setup path.
  *
- * @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.  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.
- *
  * @reserved_size, if non-zero, specifies the amount of bytes to
  * reserve after the static area in the first chunk.  This reserves
  * the first chunk such that it's available only through reserved
@@ -1031,8 +1258,7 @@ 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,
+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)
 {
@@ -1041,8 +1267,7 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
         size_t size_sum = static_size + reserved_size +
                           (dyn_size >= 0 ? dyn_size : 0);
         struct pcpu_chunk *schunk, *dchunk = NULL;
-        unsigned int cpu;
-        int i, nr_pages;
+        int i;
 
         /* santiy checks */
         BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC ||
@@ -1056,8 +1281,8 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
         pcpu_unit_pages = unit_size >> PAGE_SHIFT;
         pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
         pcpu_chunk_size = num_possible_cpus() * pcpu_unit_size;
-        pcpu_chunk_struct_size = sizeof(struct pcpu_chunk)
-                + num_possible_cpus() * pcpu_unit_pages * sizeof(struct page *);
+        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;
@@ -1087,8 +1312,8 @@ 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;
@@ -1106,38 +1331,19 @@ 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;
         }
 
-        /* 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);
-        }
-
         /* link the first chunk in */
         pcpu_first_chunk = dchunk ?: schunk;
         pcpu_chunk_relocate(pcpu_first_chunk, -1);
@@ -1160,23 +1366,6 @@ static size_t pcpu_calc_fc_sizes(size_t static_size, size_t reserved_size,
         return size_sum;
 }
 
-/*
- * 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)
-{
-        size_t off = (size_t)pageno << PAGE_SHIFT;
-
-        if (off >= pcpue_size)
-                return NULL;
-
-        return virt_to_page(pcpue_ptr + cpu * pcpue_unit_size + off);
-}
-
 /**
  * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
  * @static_size: the size of static percpu area in bytes
@@ -1207,18 +1396,19 @@ static struct page * __init pcpue_get_page(unsigned int cpu, int pageno)
 ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_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 = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size);
+        size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size);
 
-        pcpue_unit_size = max_t(size_t, pcpue_size, PCPU_MIN_UNIT_SIZE);
-        chunk_size = pcpue_unit_size * num_possible_cpus();
+        unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
+        chunk_size = unit_size * num_possible_cpus();
 
-        pcpue_ptr = __alloc_bootmem_nopanic(chunk_size, PAGE_SIZE,
-                                            __pa(MAX_DMA_ADDRESS));
-        if (!pcpue_ptr) {
+        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;
@@ -1226,33 +1416,18 @@ ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size,
 
         /* return the leftover and copy */
         for_each_possible_cpu(cpu) {
-                void *ptr = pcpue_ptr + cpu * pcpue_unit_size;
+                void *ptr = base + cpu * unit_size;
 
-                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);
         }
 
         /* 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(pcpue_get_page, static_size,
-                                      reserved_size, dyn_size,
-                                      pcpue_unit_size, pcpue_ptr);
-}
-
-/*
- * 4k page first chunk setup helper.
- */
-static struct page **pcpu4k_pages __initdata;
-static int pcpu4k_unit_pages __initdata;
-
-static struct page * __init pcpu4k_get_page(unsigned int cpu, int pageno)
-{
-        if (pageno < pcpu4k_unit_pages)
-                return pcpu4k_pages[cpu * pcpu4k_unit_pages + pageno];
-        return NULL;
+        return pcpu_setup_first_chunk(static_size, reserved_size, dyn_size,
+                                      unit_size, base);
 }
 
 /**
@@ -1279,23 +1454,25 @@ ssize_t __init pcpu_4k_first_chunk(size_t static_size, size_t reserved_size,
                                    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;
 
-        pcpu4k_unit_pages = PFN_UP(max_t(size_t, static_size + reserved_size,
-                                         PCPU_MIN_UNIT_SIZE));
+        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(pcpu4k_unit_pages * num_possible_cpus() *
-                               sizeof(pcpu4k_pages[0]));
-        pcpu4k_pages = alloc_bootmem(pages_size);
+        pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
+                               sizeof(pages[0]));
+        pages = alloc_bootmem(pages_size);
 
         /* allocate pages */
         j = 0;
         for_each_possible_cpu(cpu)
-                for (i = 0; i < pcpu4k_unit_pages; i++) {
+                for (i = 0; i < unit_pages; i++) {
                         void *ptr;
 
                         ptr = alloc_fn(cpu, PAGE_SIZE);
@@ -1304,25 +1481,24 @@ ssize_t __init pcpu_4k_first_chunk(size_t static_size, size_t reserved_size,
                                            "4k page for cpu%u\n", cpu);
                                 goto enomem;
                         }
-                        pcpu4k_pages[j++] = virt_to_page(ptr);
+                        pages[j++] = virt_to_page(ptr);
                 }
 
         /* allocate vm area, map the pages and copy static data */
         vm.flags = VM_ALLOC;
-        vm.size = num_possible_cpus() * pcpu4k_unit_pages << PAGE_SHIFT;
+        vm.size = num_possible_cpus() * 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 * pcpu4k_unit_pages << PAGE_SHIFT);
+                        (cpu * unit_pages << PAGE_SHIFT);
 
-                for (i = 0; i < pcpu4k_unit_pages; i++)
+                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,
-                                       &pcpu4k_pages[cpu * pcpu4k_unit_pages],
-                                       pcpu4k_unit_pages);
+                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);
 
@@ -1340,19 +1516,18 @@ ssize_t __init pcpu_4k_first_chunk(size_t static_size, size_t reserved_size,
 
         /* we're ready, commit */
         pr_info("PERCPU: %d 4k pages per cpu, static data %zu bytes\n",
-                pcpu4k_unit_pages, static_size);
+                unit_pages, static_size);
 
-        ret = pcpu_setup_first_chunk(pcpu4k_get_page, static_size,
-                                     reserved_size, -1,
-                                     pcpu4k_unit_pages << PAGE_SHIFT, vm.addr);
+        ret = pcpu_setup_first_chunk(static_size, reserved_size, -1,
+                                     unit_pages << PAGE_SHIFT, vm.addr);
         goto out_free_ar;
 
 enomem:
         while (--j >= 0)
-                free_fn(page_address(pcpu4k_pages[j]), PAGE_SIZE);
+                free_fn(page_address(pages[j]), PAGE_SIZE);
         ret = -ENOMEM;
 out_free_ar:
-        free_bootmem(__pa(pcpu4k_pages), pages_size);
+        free_bootmem(__pa(pages), pages_size);
         return ret;
 }
 
@@ -1370,16 +1545,6 @@ static size_t pcpul_unit_size;
 static struct pcpul_ent *pcpul_map;
 static struct vm_struct pcpul_vm;
 
-static struct page * __init pcpul_get_page(unsigned int cpu, int pageno)
-{
-        size_t off = (size_t)pageno << PAGE_SHIFT;
-
-        if (off >= pcpul_size)
-                return NULL;
-
-        return virt_to_page(pcpul_map[cpu].ptr + off);
-}
-
 /**
  * pcpu_lpage_first_chunk - remap the first percpu chunk using large page
  * @static_size: the size of static percpu area in bytes
@@ -1475,9 +1640,8 @@ ssize_t __init pcpu_lpage_first_chunk(size_t static_size, size_t reserved_size,
         pr_info("PERCPU: Remapped at %p with large pages, static data "
                 "%zu bytes\n", pcpul_vm.addr, static_size);
 
-        ret = pcpu_setup_first_chunk(pcpul_get_page, static_size,
-                                     reserved_size, dyn_size, pcpul_unit_size,
-                                     pcpul_vm.addr);
+        ret = pcpu_setup_first_chunk(static_size, reserved_size, dyn_size,
+                                     pcpul_unit_size, pcpul_vm.addr);
 
         /* sort pcpul_map array for pcpu_lpage_remapped() */
         for (i = 0; i < num_possible_cpus() - 1; i++)