4 files changed, 389 insertions, 244 deletions

diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index 9856d866b77b..a42a4a744d14 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1475,17 +1475,29 @@ static void __init pcpu_map_range(unsigned long start, unsigned long end,
 
 void __init setup_per_cpu_areas(void)
 {
-        size_t dyn_size, static_size = __per_cpu_end - __per_cpu_start;
         static struct vm_struct vm;
+        struct pcpu_alloc_info *ai;
         unsigned long delta, cpu;
         size_t size_sum, pcpu_unit_size;
         size_t ptrs_size;
         void **ptrs;
 
-        size_sum = PFN_ALIGN(static_size + PERCPU_MODULE_RESERVE +
+        ai = pcpu_alloc_alloc_info(1, nr_cpu_ids);
+
+        ai->static_size = __per_cpu_end - __per_cpu_start;
+        ai->reserved_size = PERCPU_MODULE_RESERVE;
+
+        size_sum = PFN_ALIGN(ai->static_size + ai->reserved_size +
                              PERCPU_DYNAMIC_RESERVE);
-        dyn_size = size_sum - static_size - PERCPU_MODULE_RESERVE;
 
+        ai->dyn_size = size_sum - ai->static_size - ai->reserved_size;
+        ai->unit_size = PCPU_CHUNK_SIZE;
+        ai->atom_size = PCPU_CHUNK_SIZE;
+        ai->alloc_size = PCPU_CHUNK_SIZE;
+        ai->groups[0].nr_units = nr_cpu_ids;
+
+        for_each_possible_cpu(cpu)
+                ai->groups[0].cpu_map[cpu] = cpu;
 
         ptrs_size = PFN_ALIGN(nr_cpu_ids * sizeof(ptrs[0]));
         ptrs = alloc_bootmem(ptrs_size);
@@ -1497,7 +1509,7 @@ void __init setup_per_cpu_areas(void)
                 free_bootmem(__pa(ptrs[cpu] + size_sum),
                              PCPU_CHUNK_SIZE - size_sum);
 
-                memcpy(ptrs[cpu], __per_cpu_load, static_size);
+                memcpy(ptrs[cpu], __per_cpu_load, ai->static_size);
         }
 
         /* allocate address and map */
@@ -1514,9 +1526,7 @@ void __init setup_per_cpu_areas(void)
                 pcpu_map_range(start, end, virt_to_page(ptrs[cpu]));
         }
 
-        pcpu_unit_size = pcpu_setup_first_chunk(static_size,
-                                                PERCPU_MODULE_RESERVE, dyn_size,
-                                                PCPU_CHUNK_SIZE, vm.addr, NULL);
+        pcpu_unit_size = pcpu_setup_first_chunk(ai, vm.addr);
 
         free_bootmem(__pa(ptrs), ptrs_size);
 
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index 660cde133141..db5f9c49fec5 100644
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -161,9 +161,7 @@ static ssize_t __init setup_pcpu_lpage(bool chosen)
 {
         size_t reserve = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE;
         size_t dyn_size = reserve - PERCPU_FIRST_CHUNK_RESERVE;
-        size_t unit_map_size, unit_size;
-        int *unit_map;
-        int nr_units;
+        struct pcpu_alloc_info *ai;
         ssize_t ret;
 
         /* on non-NUMA, embedding is better */
@@ -177,26 +175,22 @@ static ssize_t __init setup_pcpu_lpage(bool chosen)
         }
 
         /* allocate and build unit_map */
-        unit_map_size = nr_cpu_ids * sizeof(int);
-        unit_map = alloc_bootmem_nopanic(unit_map_size);
-        if (!unit_map) {
-                pr_warning("PERCPU: failed to allocate unit_map\n");
-                return -ENOMEM;
+        ai = pcpu_build_alloc_info(PERCPU_FIRST_CHUNK_RESERVE, dyn_size,
+                                   PMD_SIZE, pcpu_lpage_cpu_distance);
+        if (IS_ERR(ai)) {
+                pr_warning("PERCPU: failed to build unit_map (%ld)\n",
+                           PTR_ERR(ai));
+                return PTR_ERR(ai);
         }
 
-        ret = pcpu_lpage_build_unit_map(PERCPU_FIRST_CHUNK_RESERVE,
-                                        &dyn_size, &unit_size, PMD_SIZE,
-                                        unit_map, pcpu_lpage_cpu_distance);
-        if (ret < 0) {
-                pr_warning("PERCPU: failed to build unit_map\n");
-                goto out_free;
-        }
-        nr_units = ret;
-
         /* do the parameters look okay? */
         if (!chosen) {
                 size_t vm_size = VMALLOC_END - VMALLOC_START;
-                size_t tot_size = nr_units * unit_size;
+                size_t tot_size = 0;
+                int group;
+
+                for (group = 0; group < ai->nr_groups; group++)
+                        tot_size += ai->unit_size * ai->groups[group].nr_units;
 
                 /* don't consume more than 20% of vmalloc area */
                 if (tot_size > vm_size / 5) {
@@ -207,12 +201,10 @@ static ssize_t __init setup_pcpu_lpage(bool chosen)
                 }
         }
 
-        ret = pcpu_lpage_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, dyn_size,
-                                     unit_size, PMD_SIZE, unit_map, nr_units,
-                                     pcpu_fc_alloc, pcpu_fc_free, pcpul_map);
+        ret = pcpu_lpage_first_chunk(ai, pcpu_fc_alloc, pcpu_fc_free,
+                                     pcpul_map);
 out_free:
-        if (ret < 0)
-                free_bootmem(__pa(unit_map), unit_map_size);
+        pcpu_free_alloc_info(ai);
         return ret;
 }
 #else
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 570fb18de2ba..77b86be8ce4f 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -59,6 +59,25 @@
 extern void *pcpu_base_addr;
 extern const int *pcpu_unit_map;
 
+struct pcpu_group_info {
+        int                     nr_units;       /* aligned # of units */
+        unsigned long           base_offset;    /* base address offset */
+        unsigned int            *cpu_map;       /* unit->cpu map, empty
+                                                 * entries contain NR_CPUS */
+};
+
+struct pcpu_alloc_info {
+        size_t                  static_size;
+        size_t                  reserved_size;
+        size_t                  dyn_size;
+        size_t                  unit_size;
+        size_t                  atom_size;
+        size_t                  alloc_size;
+        size_t                  __ai_size;      /* internal, don't use */
+        int                     nr_groups;      /* 0 if grouping unnecessary */
+        struct pcpu_group_info  groups[];
+};
+
 enum pcpu_fc {
         PCPU_FC_AUTO,
         PCPU_FC_EMBED,
@@ -78,18 +97,17 @@ typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
 typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
 typedef void (*pcpu_fc_map_fn_t)(void *ptr, size_t size, void *addr);
 
-#ifdef CONFIG_NEED_PER_CPU_LPAGE_FIRST_CHUNK
-extern int __init pcpu_lpage_build_unit_map(
-                                size_t reserved_size, ssize_t *dyn_sizep,
-                                size_t *unit_sizep, size_t lpage_size,
-                                int *unit_map,
+extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
+                                                             int nr_units);
+extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
+
+extern struct pcpu_alloc_info * __init pcpu_build_alloc_info(
+                                size_t reserved_size, ssize_t dyn_size,
+                                size_t atom_size,
                                 pcpu_fc_cpu_distance_fn_t cpu_distance_fn);
-#endif
 
-extern size_t __init pcpu_setup_first_chunk(
-                                size_t static_size, size_t reserved_size,
-                                size_t dyn_size, size_t unit_size,
-                                void *base_addr, const int *unit_map);
+extern size_t __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
+                                            void *base_addr);
 
 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
 extern ssize_t __init pcpu_embed_first_chunk(
@@ -106,9 +124,7 @@ extern ssize_t __init pcpu_page_first_chunk(
 
 #ifdef CONFIG_NEED_PER_CPU_LPAGE_FIRST_CHUNK
 extern ssize_t __init pcpu_lpage_first_chunk(
-                                size_t reserved_size, size_t dyn_size,
-                                size_t unit_size, size_t lpage_size,
-                                const int *unit_map, int nr_units,
+                                const struct pcpu_alloc_info *ai,
                                 pcpu_fc_alloc_fn_t alloc_fn,
                                 pcpu_fc_free_fn_t free_fn,
                                 pcpu_fc_map_fn_t map_fn);
diff --git a/mm/percpu.c b/mm/percpu.c
index 2b9c4b2a2fc0..99f7fa682722 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -58,6 +58,7 @@
 
 #include <linux/bitmap.h>
 #include <linux/bootmem.h>
+#include <linux/err.h>
 #include <linux/list.h>
 #include <linux/log2.h>
 #include <linux/mm.h>
@@ -1245,53 +1246,108 @@ static inline size_t pcpu_calc_fc_sizes(size_t static_size,
         return size_sum;
 }
 
-#ifdef CONFIG_NEED_PER_CPU_LPAGE_FIRST_CHUNK
 /**
- * pcpu_lpage_build_unit_map - build unit_map for large page remapping
+ * pcpu_alloc_alloc_info - allocate percpu allocation info
+ * @nr_groups: the number of groups
+ * @nr_units: the number of units
+ *
+ * Allocate ai which is large enough for @nr_groups groups containing
+ * @nr_units units.  The returned ai's groups[0].cpu_map points to the
+ * cpu_map array which is long enough for @nr_units and filled with
+ * NR_CPUS.  It's the caller's responsibility to initialize cpu_map
+ * pointer of other groups.
+ *
+ * RETURNS:
+ * Pointer to the allocated pcpu_alloc_info on success, NULL on
+ * failure.
+ */
+struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
+                                                      int nr_units)
+{
+        struct pcpu_alloc_info *ai;
+        size_t base_size, ai_size;
+        void *ptr;
+        int unit;
+
+        base_size = ALIGN(sizeof(*ai) + nr_groups * sizeof(ai->groups[0]),
+                          __alignof__(ai->groups[0].cpu_map[0]));
+        ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]);
+
+        ptr = alloc_bootmem_nopanic(PFN_ALIGN(ai_size));
+        if (!ptr)
+                return NULL;
+        ai = ptr;
+        ptr += base_size;
+
+        ai->groups[0].cpu_map = ptr;
+
+        for (unit = 0; unit < nr_units; unit++)
+                ai->groups[0].cpu_map[unit] = NR_CPUS;
+
+        ai->nr_groups = nr_groups;
+        ai->__ai_size = PFN_ALIGN(ai_size);
+
+        return ai;
+}
+
+/**
+ * pcpu_free_alloc_info - free percpu allocation info
+ * @ai: pcpu_alloc_info to free
+ *
+ * Free @ai which was allocated by pcpu_alloc_alloc_info().
+ */
+void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
+{
+        free_bootmem(__pa(ai), ai->__ai_size);
+}
+
+/**
+ * pcpu_build_alloc_info - build alloc_info considering distances between CPUs
  * @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
+ * @dyn_size: free size for dynamic allocation in bytes, -1 for auto
+ * @atom_size: allocation atom size
+ * @cpu_distance_fn: callback to determine distance between cpus, optional
  *
- * This function builds cpu -> unit map and determine other parameters
- * considering needed percpu size, large page size and distances
- * between CPUs in NUMA.
+ * This function determines grouping of units, their mappings to cpus
+ * and other parameters considering needed percpu size, allocation
+ * atom size and distances between CPUs.
  *
- * 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.
+ * Groups are always mutliples of atom size and CPUs which are of
+ * LOCAL_DISTANCE both ways are grouped together and share space for
+ * units in the same group.  The returned configuration is guaranteed
+ * to have CPUs on different nodes on different groups 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.
+ * On success, pointer to the new allocation_info is returned.  On
+ * failure, ERR_PTR value is returned.
  */
-int __init pcpu_lpage_build_unit_map(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)
+struct pcpu_alloc_info * __init pcpu_build_alloc_info(
+                                size_t reserved_size, ssize_t dyn_size,
+                                size_t atom_size,
+                                pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
 {
         static int group_map[NR_CPUS] __initdata;
         static int group_cnt[NR_CPUS] __initdata;
         const size_t static_size = __per_cpu_end - __per_cpu_start;
-        int group_cnt_max = 0;
+        int group_cnt_max = 0, nr_groups = 1, nr_units = 0;
         size_t size_sum, min_unit_size, alloc_size;
         int upa, max_upa, uninitialized_var(best_upa);  /* units_per_alloc */
-        int last_allocs;
+        int last_allocs, group, unit;
         unsigned int cpu, tcpu;
-        int group, unit;
+        struct pcpu_alloc_info *ai;
+        unsigned int *cpu_map;
 
         /*
          * Determine min_unit_size, alloc_size and max_upa such that
-         * alloc_size is multiple of lpage_size and is the smallest
+         * alloc_size is multiple of atom_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);
+        size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size);
         min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
 
-        alloc_size = roundup(min_unit_size, lpage_size);
+        alloc_size = roundup(min_unit_size, atom_size);
         upa = alloc_size / min_unit_size;
         while (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
                 upa--;
@@ -1304,10 +1360,11 @@ int __init pcpu_lpage_build_unit_map(size_t reserved_size, ssize_t *dyn_sizep,
                 for_each_possible_cpu(tcpu) {
                         if (cpu == tcpu)
                                 break;
-                        if (group_map[tcpu] == group &&
+                        if (group_map[tcpu] == group && cpu_distance_fn &&
                             (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE ||
                              cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) {
                                 group++;
+                                nr_groups = max(nr_groups, group + 1);
                                 goto next_group;
                         }
                 }
@@ -1328,7 +1385,7 @@ int __init pcpu_lpage_build_unit_map(size_t reserved_size, ssize_t *dyn_sizep,
                 if (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
                         continue;
 
-                for (group = 0; group_cnt[group]; group++) {
+                for (group = 0; group < nr_groups; group++) {
                         int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
                         allocs += this_allocs;
                         wasted += this_allocs * upa - group_cnt[group];
@@ -1348,75 +1405,122 @@ int __init pcpu_lpage_build_unit_map(size_t reserved_size, ssize_t *dyn_sizep,
                 last_allocs = allocs;
                 best_upa = upa;
         }
-        *unit_sizep = alloc_size / best_upa;
+        upa = best_upa;
+
+        /* allocate and fill alloc_info */
+        for (group = 0; group < nr_groups; group++)
+                nr_units += roundup(group_cnt[group], upa);
+
+        ai = pcpu_alloc_alloc_info(nr_groups, nr_units);
+        if (!ai)
+                return ERR_PTR(-ENOMEM);
+        cpu_map = ai->groups[0].cpu_map;
+
+        for (group = 0; group < nr_groups; group++) {
+                ai->groups[group].cpu_map = cpu_map;
+                cpu_map += roundup(group_cnt[group], upa);
+        }
+
+        ai->static_size = static_size;
+        ai->reserved_size = reserved_size;
+        ai->dyn_size = dyn_size;
+        ai->unit_size = alloc_size / upa;
+        ai->atom_size = atom_size;
+        ai->alloc_size = alloc_size;
+
+        for (group = 0, unit = 0; group_cnt[group]; group++) {
+                struct pcpu_group_info *gi = &ai->groups[group];
+
+                /*
+                 * Initialize base_offset as if all groups are located
+                 * back-to-back.  The caller should update this to
+                 * reflect actual allocation.
+                 */
+                gi->base_offset = unit * ai->unit_size;
 
-        /* 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);
+                                gi->cpu_map[gi->nr_units++] = cpu;
+                gi->nr_units = roundup(gi->nr_units, upa);
+                unit += gi->nr_units;
         }
+        BUG_ON(unit != nr_units);
 
-        return unit;    /* unit contains aligned number of units */
+        return ai;
 }
 
-static bool __init pcpul_unit_to_cpu(int unit, const int *unit_map,
-                                     unsigned int *cpup);
-
-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)
+/**
+ * pcpu_dump_alloc_info - print out information about pcpu_alloc_info
+ * @lvl: loglevel
+ * @ai: allocation info to dump
+ *
+ * Print out information about @ai using loglevel @lvl.
+ */
+static void pcpu_dump_alloc_info(const char *lvl,
+                                 const struct pcpu_alloc_info *ai)
 {
-        int width = 1, v = nr_units;
+        int group_width = 1, cpu_width = 1, width;
         char empty_str[] = "--------";
-        int upl, lpl;   /* units per lpage, lpage per line */
-        unsigned int cpu;
-        int lpage, unit;
+        int alloc = 0, alloc_end = 0;
+        int group, v;
+        int upa, apl;   /* units per alloc, allocs per line */
+
+        v = ai->nr_groups;
+        while (v /= 10)
+                group_width++;
 
+        v = num_possible_cpus();
         while (v /= 10)
-                width++;
-        empty_str[min_t(int, width, sizeof(empty_str) - 1)] = '\0';
+                cpu_width++;
+        empty_str[min_t(int, cpu_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));
+        upa = ai->alloc_size / ai->unit_size;
+        width = upa * (cpu_width + 1) + group_width + 3;
+        apl = rounddown_pow_of_two(max(60 / width, 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);
+        printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
+               lvl, ai->static_size, ai->reserved_size, ai->dyn_size,
+               ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size);
 
-        for (lpage = 0, unit = 0; unit < nr_units; unit++) {
-                if (!(unit % upl)) {
-                        if (!(lpage++ % lpl)) {
+        for (group = 0; group < ai->nr_groups; group++) {
+                const struct pcpu_group_info *gi = &ai->groups[group];
+                int unit = 0, unit_end = 0;
+
+                BUG_ON(gi->nr_units % upa);
+                for (alloc_end += gi->nr_units / upa;
+                     alloc < alloc_end; alloc++) {
+                        if (!(alloc % apl)) {
                                 printk("\n");
-                                printk("%spcpu-lpage: ", lvl);
-                        } else
-                                printk("| ");
+                                printk("%spcpu-alloc: ", lvl);
+                        }
+                        printk("[%0*d] ", group_width, group);
+
+                        for (unit_end += upa; unit < unit_end; unit++)
+                                if (gi->cpu_map[unit] != NR_CPUS)
+                                        printk("%0*d ", cpu_width,
+                                               gi->cpu_map[unit]);
+                                else
+                                        printk("%s ", empty_str);
                 }
-                if (pcpul_unit_to_cpu(unit, unit_map, &cpu))
-                        printk("%0*d ", width, cpu);
-                else
-                        printk("%s ", empty_str);
         }
         printk("\n");
 }
-#endif
 
 /**
  * pcpu_setup_first_chunk - initialize the first percpu chunk
- * @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
- * @unit_size: unit size in bytes, must be multiple of PAGE_SIZE
+ * @ai: pcpu_alloc_info describing how to percpu area is shaped
  * @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.
  *
- * @reserved_size, if non-zero, specifies the amount of bytes to
+ * @ai contains all information necessary to initialize the first
+ * chunk and prime the dynamic percpu allocator.
+ *
+ * @ai->static_size is the size of static percpu area.
+ *
+ * @ai->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
  * percpu allocation.  This is primarily used to serve module percpu
@@ -1424,13 +1528,26 @@ static void __init pcpul_lpage_dump_cfg(const char *lvl, size_t static_size,
  * limited offset range for symbol relocations to guarantee module
  * percpu symbols fall inside the relocatable range.
  *
- * @dyn_size determines the number of bytes available for dynamic
- * allocation in the first chunk.  The area between @static_size +
- * @reserved_size + @dyn_size and @unit_size is unused.
+ * @ai->dyn_size determines the number of bytes available for dynamic
+ * allocation in the first chunk.  The area between @ai->static_size +
+ * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
  *
- * @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.
+ * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
+ * and equal to or larger than @ai->static_size + @ai->reserved_size +
+ * @ai->dyn_size.
+ *
+ * @ai->atom_size is the allocation atom size and used as alignment
+ * for vm areas.
+ *
+ * @ai->alloc_size is the allocation size and always multiple of
+ * @ai->atom_size.  This is larger than @ai->atom_size if
+ * @ai->unit_size is larger than @ai->atom_size.
+ *
+ * @ai->nr_groups and @ai->groups describe virtual memory layout of
+ * percpu areas.  Units which should be colocated are put into the
+ * same group.  Dynamic VM areas will be allocated according to these
+ * groupings.  If @ai->nr_groups is zero, a single group containing
+ * all units is assumed.
  *
  * The caller should have mapped the first chunk at @base_addr and
  * copied static data to each unit.
@@ -1446,70 +1563,63 @@ static void __init pcpul_lpage_dump_cfg(const char *lvl, size_t static_size,
  * The determined pcpu_unit_size which can be used to initialize
  * percpu access.
  */
-size_t __init pcpu_setup_first_chunk(size_t static_size, size_t reserved_size,
-                                     size_t dyn_size, size_t unit_size,
-                                     void *base_addr, const int *unit_map)
+size_t __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
+                                     void *base_addr)
 {
         static struct vm_struct first_vm;
         static int smap[2], dmap[2];
-        size_t size_sum = static_size + reserved_size + dyn_size;
+        size_t dyn_size = ai->dyn_size;
+        size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
         struct pcpu_chunk *schunk, *dchunk = NULL;
-        unsigned int cpu, tcpu;
-        int i;
+        unsigned int cpu;
+        int *unit_map;
+        int group, unit, i;
 
         /* sanity checks */
         BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC ||
                      ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC);
-        BUG_ON(!static_size);
+        BUG_ON(ai->nr_groups <= 0);
+        BUG_ON(!ai->static_size);
         BUG_ON(!base_addr);
-        BUG_ON(unit_size < size_sum);
-        BUG_ON(unit_size & ~PAGE_MASK);
-        BUG_ON(unit_size < PCPU_MIN_UNIT_SIZE);
+        BUG_ON(ai->unit_size < size_sum);
+        BUG_ON(ai->unit_size & ~PAGE_MASK);
+        BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
+
+        pcpu_dump_alloc_info(KERN_DEBUG, ai);
 
         /* 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);
-                        }
+        unit_map = alloc_bootmem(nr_cpu_ids * sizeof(unit_map[0]));
 
-                        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;
+        for (cpu = 0; cpu < nr_cpu_ids; cpu++)
+                unit_map[cpu] = NR_CPUS;
+        pcpu_first_unit_cpu = NR_CPUS;
 
-                /* #units == #cpus, identity mapped */
-                identity_map = alloc_bootmem(nr_cpu_ids *
-                                             sizeof(identity_map[0]));
+        for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
+                const struct pcpu_group_info *gi = &ai->groups[group];
 
-                for_each_possible_cpu(cpu)
-                        identity_map[cpu] = cpu;
+                for (i = 0; i < gi->nr_units; i++) {
+                        cpu = gi->cpu_map[i];
+                        if (cpu == NR_CPUS)
+                                continue;
 
-                pcpu_first_unit_cpu = 0;
-                pcpu_last_unit_cpu = pcpu_nr_units - 1;
-                pcpu_nr_units = nr_cpu_ids;
-                pcpu_unit_map = identity_map;
+                        BUG_ON(cpu > nr_cpu_ids || !cpu_possible(cpu));
+                        BUG_ON(unit_map[cpu] != NR_CPUS);
+
+                        unit_map[cpu] = unit + i;
+                        if (pcpu_first_unit_cpu == NR_CPUS)
+                                pcpu_first_unit_cpu = cpu;
+                }
         }
+        pcpu_last_unit_cpu = cpu;
+        pcpu_nr_units = unit;
+
+        for_each_possible_cpu(cpu)
+                BUG_ON(unit_map[cpu] == NR_CPUS);
+
+        pcpu_unit_map = unit_map;
 
         /* determine basic parameters */
-        pcpu_unit_pages = unit_size >> PAGE_SHIFT;
+        pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
         pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
         pcpu_chunk_size = pcpu_nr_units * pcpu_unit_size;
         pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
@@ -1543,17 +1653,17 @@ size_t __init pcpu_setup_first_chunk(size_t static_size, size_t reserved_size,
         schunk->immutable = true;
         bitmap_fill(schunk->populated, pcpu_unit_pages);
 
-        if (reserved_size) {
-                schunk->free_size = reserved_size;
+        if (ai->reserved_size) {
+                schunk->free_size = ai->reserved_size;
                 pcpu_reserved_chunk = schunk;
-                pcpu_reserved_chunk_limit = static_size + reserved_size;
+                pcpu_reserved_chunk_limit = ai->static_size + ai->reserved_size;
         } else {
                 schunk->free_size = dyn_size;
                 dyn_size = 0;                   /* dynamic area covered */
         }
         schunk->contig_hint = schunk->free_size;
 
-        schunk->map[schunk->map_used++] = -static_size;
+        schunk->map[schunk->map_used++] = -ai->static_size;
         if (schunk->free_size)
                 schunk->map[schunk->map_used++] = schunk->free_size;
 
@@ -1643,44 +1753,47 @@ early_param("percpu_alloc", percpu_alloc_setup);
  */
 ssize_t __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size)
 {
-        const size_t static_size = __per_cpu_end - __per_cpu_start;
-        size_t size_sum, unit_size, chunk_size;
+        struct pcpu_alloc_info *ai;
+        size_t size_sum, chunk_size;
         void *base;
-        unsigned int cpu;
+        int unit;
+        ssize_t ret;
 
-        /* determine parameters and allocate */
-        size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size);
+        ai = pcpu_build_alloc_info(reserved_size, dyn_size, PAGE_SIZE, NULL);
+        if (IS_ERR(ai))
+                return PTR_ERR(ai);
+        BUG_ON(ai->nr_groups != 1);
+        BUG_ON(ai->groups[0].nr_units != num_possible_cpus());
 
-        unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
-        chunk_size = unit_size * nr_cpu_ids;
+        size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
+        chunk_size = ai->unit_size * num_possible_cpus();
 
         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;
+                ret = -ENOMEM;
+                goto out_free_ai;
         }
 
         /* return the leftover and copy */
-        for (cpu = 0; cpu < nr_cpu_ids; cpu++) {
-                void *ptr = base + cpu * unit_size;
-
-                if (cpu_possible(cpu)) {
-                        free_bootmem(__pa(ptr + size_sum),
-                                     unit_size - size_sum);
-                        memcpy(ptr, __per_cpu_load, static_size);
-                } else
-                        free_bootmem(__pa(ptr), unit_size);
+        for (unit = 0; unit < num_possible_cpus(); unit++) {
+                void *ptr = base + unit * ai->unit_size;
+
+                free_bootmem(__pa(ptr + size_sum), ai->unit_size - size_sum);
+                memcpy(ptr, __per_cpu_load, ai->static_size);
         }
 
         /* we're ready, commit */
         pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
-                PFN_DOWN(size_sum), base, static_size, reserved_size, dyn_size,
-                unit_size);
+                PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size,
+                ai->dyn_size, ai->unit_size);
 
-        return pcpu_setup_first_chunk(static_size, reserved_size, dyn_size,
-                                      unit_size, base, NULL);
+        ret = pcpu_setup_first_chunk(ai, base);
+out_free_ai:
+        pcpu_free_alloc_info(ai);
+        return ret;
 }
 #endif /* CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK ||
           !CONFIG_HAVE_SETUP_PER_CPU_AREA */
@@ -1709,31 +1822,34 @@ ssize_t __init pcpu_page_first_chunk(size_t reserved_size,
                                      pcpu_fc_populate_pte_fn_t populate_pte_fn)
 {
         static struct vm_struct vm;
-        const size_t static_size = __per_cpu_end - __per_cpu_start;
-        ssize_t dyn_size = -1;
-        size_t size_sum, unit_size;
+        struct pcpu_alloc_info *ai;
         char psize_str[16];
         int unit_pages;
         size_t pages_size;
         struct page **pages;
-        unsigned int cpu;
-        int i, j;
+        int unit, i, j;
         ssize_t ret;
 
         snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10);
 
-        size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size);
-        unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
-        unit_pages = unit_size >> PAGE_SHIFT;
+        ai = pcpu_build_alloc_info(reserved_size, -1, PAGE_SIZE, NULL);
+        if (IS_ERR(ai))
+                return PTR_ERR(ai);
+        BUG_ON(ai->nr_groups != 1);
+        BUG_ON(ai->groups[0].nr_units != num_possible_cpus());
+
+        unit_pages = ai->unit_size >> PAGE_SHIFT;
 
         /* unaligned allocations can't be freed, round up to page size */
-        pages_size = PFN_ALIGN(unit_pages * nr_cpu_ids * sizeof(pages[0]));
+        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 (unit = 0; unit < num_possible_cpus(); unit++)
                 for (i = 0; i < unit_pages; i++) {
+                        unsigned int cpu = ai->groups[0].cpu_map[unit];
                         void *ptr;
 
                         ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE);
@@ -1747,18 +1863,18 @@ ssize_t __init pcpu_page_first_chunk(size_t reserved_size,
 
         /* allocate vm area, map the pages and copy static data */
         vm.flags = VM_ALLOC;
-        vm.size = nr_cpu_ids * unit_size;
+        vm.size = num_possible_cpus() * ai->unit_size;
         vm_area_register_early(&vm, PAGE_SIZE);
 
-        for_each_possible_cpu(cpu) {
+        for (unit = 0; unit < num_possible_cpus(); unit++) {
                 unsigned long unit_addr =
-                        (unsigned long)vm.addr + cpu * unit_size;
+                        (unsigned long)vm.addr + unit * ai->unit_size;
 
                 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],
+                ret = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages],
                                        unit_pages);
                 if (ret < 0)
                         panic("failed to map percpu area, err=%zd\n", ret);
@@ -1772,16 +1888,15 @@ ssize_t __init pcpu_page_first_chunk(size_t reserved_size,
                  */
 
                 /* copy static data */
-                memcpy((void *)unit_addr, __per_cpu_load, static_size);
+                memcpy((void *)unit_addr, __per_cpu_load, ai->static_size);
         }
 
         /* we're ready, commit */
         pr_info("PERCPU: %d %s pages/cpu @%p s%zu r%zu d%zu\n",
-                unit_pages, psize_str, vm.addr, static_size, reserved_size,
-                dyn_size);
+                unit_pages, psize_str, vm.addr, ai->static_size,
+                ai->reserved_size, ai->dyn_size);
 
-        ret = pcpu_setup_first_chunk(static_size, reserved_size, dyn_size,
-                                     unit_size, vm.addr, NULL);
+        ret = pcpu_setup_first_chunk(ai, vm.addr);
         goto out_free_ar;
 
 enomem:
@@ -1790,6 +1905,7 @@ enomem:
         ret = -ENOMEM;
 out_free_ar:
         free_bootmem(__pa(pages), pages_size);
+        pcpu_free_alloc_info(ai);
         return ret;
 }
 #endif /* CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK */
@@ -1805,38 +1921,50 @@ 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,
+static bool __init pcpul_unit_to_cpu(int unit, const struct pcpu_alloc_info *ai,
                                      unsigned int *cpup)
 {
-        unsigned int cpu;
+        int group, cunit;
 
-        for_each_possible_cpu(cpu)
-                if (unit_map[cpu] == unit) {
+        for (group = 0, cunit = 0; group < ai->nr_groups; group++) {
+                const struct pcpu_group_info *gi = &ai->groups[group];
+
+                if (unit < cunit + gi->nr_units) {
                         if (cpup)
-                                *cpup = cpu;
+                                *cpup = gi->cpu_map[unit - cunit];
                         return true;
                 }
+                cunit += gi->nr_units;
+        }
 
         return false;
 }
 
+static int __init pcpul_cpu_to_unit(int cpu, const struct pcpu_alloc_info *ai)
+{
+        int group, unit, i;
+
+        for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
+                const struct pcpu_group_info *gi = &ai->groups[group];
+
+                for (i = 0; i < gi->nr_units; i++)
+                        if (gi->cpu_map[i] == cpu)
+                                return unit + i;
+        }
+        BUG();
+}
+
 /**
  * pcpu_lpage_first_chunk - remap the first percpu chunk using large page
- * @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
+ * @ai: pcpu_alloc_info
  * @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
+ * Unlike other helpers, the caller should provide fully initialized
+ * @ai.  This can be done using pcpu_build_alloc_info().  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
@@ -1852,27 +1980,26 @@ static bool __init pcpul_unit_to_cpu(int unit, const int *unit_map,
  * 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 reserved_size, size_t dyn_size,
-                                      size_t unit_size, size_t lpage_size,
-                                      const int *unit_map, int nr_units,
+ssize_t __init pcpu_lpage_first_chunk(const struct pcpu_alloc_info *ai,
                                       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;
-        const size_t static_size = __per_cpu_end - __per_cpu_start;
-        size_t chunk_size = unit_size * nr_units;
-        size_t map_size;
+        const size_t lpage_size = ai->atom_size;
+        size_t chunk_size, map_size;
         unsigned int cpu;
         ssize_t ret;
-        int i, j, unit;
+        int i, j, unit, nr_units;
 
-        pcpul_lpage_dump_cfg(KERN_DEBUG, static_size, reserved_size, dyn_size,
-                             unit_size, lpage_size, unit_map, nr_units);
+        nr_units = 0;
+        for (i = 0; i < ai->nr_groups; i++)
+                nr_units += ai->groups[i].nr_units;
 
+        chunk_size = ai->unit_size * nr_units;
         BUG_ON(chunk_size % lpage_size);
 
-        pcpul_size = static_size + reserved_size + dyn_size;
+        pcpul_size = ai->static_size + ai->reserved_size + ai->dyn_size;
         pcpul_lpage_size = lpage_size;
         pcpul_nr_lpages = chunk_size / lpage_size;
 
@@ -1883,13 +2010,13 @@ ssize_t __init pcpu_lpage_first_chunk(size_t reserved_size, size_t dyn_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;
+                int first_unit = offset / ai->unit_size;
+                int last_unit = (offset + lpage_size - 1) / ai->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))
+                        if (pcpul_unit_to_cpu(unit, ai, &cpu))
                                 goto found;
                 continue;
         found:
@@ -1905,12 +2032,12 @@ ssize_t __init pcpu_lpage_first_chunk(size_t reserved_size, size_t dyn_size,
 
         /* return unused holes */
         for (unit = 0; unit < nr_units; unit++) {
-                size_t start = unit * unit_size;
-                size_t end = start + unit_size;
+                size_t start = unit * ai->unit_size;
+                size_t end = start + ai->unit_size;
                 size_t off, next;
 
                 /* don't free used part of occupied unit */
-                if (pcpul_unit_to_cpu(unit, unit_map, NULL))
+                if (pcpul_unit_to_cpu(unit, ai, NULL))
                         start += pcpul_size;
 
                 /* unit can span more than one page, punch the holes */
@@ -1925,7 +2052,7 @@ ssize_t __init pcpu_lpage_first_chunk(size_t reserved_size, size_t dyn_size,
         /* allocate address, map and copy */
         vm.flags = VM_ALLOC;
         vm.size = chunk_size;
-        vm_area_register_early(&vm, unit_size);
+        vm_area_register_early(&vm, ai->unit_size);
 
         for (i = 0; i < pcpul_nr_lpages; i++) {
                 if (!pcpul_map[i].ptr)
@@ -1935,15 +2062,15 @@ ssize_t __init pcpu_lpage_first_chunk(size_t reserved_size, size_t dyn_size,
         }
 
         for_each_possible_cpu(cpu)
-                memcpy(vm.addr + unit_map[cpu] * unit_size, __per_cpu_load,
-                       static_size);
+                memcpy(vm.addr + pcpul_cpu_to_unit(cpu, ai) * ai->unit_size,
+                       __per_cpu_load, ai->static_size);
 
         /* we're ready, commit */
         pr_info("PERCPU: large pages @%p s%zu r%zu d%zu u%zu\n",
-                vm.addr, static_size, reserved_size, dyn_size, unit_size);
+                vm.addr, ai->static_size, ai->reserved_size, ai->dyn_size,
+                ai->unit_size);
 
-        ret = pcpu_setup_first_chunk(static_size, reserved_size, dyn_size,
-                                     unit_size, vm.addr, unit_map);
+        ret = pcpu_setup_first_chunk(ai, vm.addr);
 
         /*
          * Sort pcpul_map array for pcpu_lpage_remapped().  Unmapped