10 files changed, 136 insertions, 96 deletions

diff --git a/mm/Kconfig b/mm/Kconfig
index 247760729593..edd300aca173 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -244,10 +244,12 @@ config DEFAULT_MMAP_MIN_ADDR
           This value can be changed after boot using the
           /proc/sys/vm/mmap_min_addr tunable.
 
+config ARCH_SUPPORTS_MEMORY_FAILURE
+        bool
 
 config MEMORY_FAILURE
         depends on MMU
-        depends on X86_MCE
+        depends on ARCH_SUPPORTS_MEMORY_FAILURE
         bool "Enable recovery from hardware memory errors"
         help
           Enables code to recover from some memory failures on systems
diff --git a/mm/filemap.c b/mm/filemap.c
index 6c84e598b4a9..ef169f37156d 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1611,7 +1611,7 @@ page_not_uptodate:
 }
 EXPORT_SYMBOL(filemap_fault);
 
-struct vm_operations_struct generic_file_vm_ops = {
+const struct vm_operations_struct generic_file_vm_ops = {
         .fault          = filemap_fault,
 };
 
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index 427dfe3ce78c..1888b2d71bb8 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -296,7 +296,7 @@ out:
         }
 }
 
-static struct vm_operations_struct xip_file_vm_ops = {
+static const struct vm_operations_struct xip_file_vm_ops = {
         .fault  = xip_file_fault,
 };
 
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 6f048fcc749c..5d7601b02874 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1721,7 +1721,7 @@ static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
         return 0;
 }
 
-struct vm_operations_struct hugetlb_vm_ops = {
+const struct vm_operations_struct hugetlb_vm_ops = {
         .fault = hugetlb_vm_op_fault,
         .open = hugetlb_vm_op_open,
         .close = hugetlb_vm_op_close,
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e2b98a6875c0..f99f5991d6bb 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -313,7 +313,8 @@ soft_limit_tree_from_page(struct page *page)
 static void
 __mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
                                 struct mem_cgroup_per_zone *mz,
-                                struct mem_cgroup_tree_per_zone *mctz)
+                                struct mem_cgroup_tree_per_zone *mctz,
+                                unsigned long long new_usage_in_excess)
 {
         struct rb_node **p = &mctz->rb_root.rb_node;
         struct rb_node *parent = NULL;
@@ -322,7 +323,9 @@ __mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
         if (mz->on_tree)
                 return;
 
-        mz->usage_in_excess = res_counter_soft_limit_excess(&mem->res);
+        mz->usage_in_excess = new_usage_in_excess;
+        if (!mz->usage_in_excess)
+                return;
         while (*p) {
                 parent = *p;
                 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
@@ -353,16 +356,6 @@ __mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
 }
 
 static void
-mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
-                                struct mem_cgroup_per_zone *mz,
-                                struct mem_cgroup_tree_per_zone *mctz)
-{
-        spin_lock(&mctz->lock);
-        __mem_cgroup_insert_exceeded(mem, mz, mctz);
-        spin_unlock(&mctz->lock);
-}
-
-static void
 mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
                                 struct mem_cgroup_per_zone *mz,
                                 struct mem_cgroup_tree_per_zone *mctz)
@@ -392,34 +385,36 @@ static bool mem_cgroup_soft_limit_check(struct mem_cgroup *mem)
 
 static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
 {
-        unsigned long long prev_usage_in_excess, new_usage_in_excess;
-        bool updated_tree = false;
+        unsigned long long excess;
         struct mem_cgroup_per_zone *mz;
         struct mem_cgroup_tree_per_zone *mctz;
-
-        mz = mem_cgroup_zoneinfo(mem, page_to_nid(page), page_zonenum(page));
+        int nid = page_to_nid(page);
+        int zid = page_zonenum(page);
         mctz = soft_limit_tree_from_page(page);
 
         /*
-         * We do updates in lazy mode, mem's are removed
-         * lazily from the per-zone, per-node rb tree
+         * Necessary to update all ancestors when hierarchy is used.
+         * because their event counter is not touched.
          */
-        prev_usage_in_excess = mz->usage_in_excess;
-
-        new_usage_in_excess = res_counter_soft_limit_excess(&mem->res);
-        if (prev_usage_in_excess) {
-                mem_cgroup_remove_exceeded(mem, mz, mctz);
-                updated_tree = true;
-        }
-        if (!new_usage_in_excess)
-                goto done;
-        mem_cgroup_insert_exceeded(mem, mz, mctz);
-
-done:
-        if (updated_tree) {
-                spin_lock(&mctz->lock);
-                mz->usage_in_excess = new_usage_in_excess;
-                spin_unlock(&mctz->lock);
+        for (; mem; mem = parent_mem_cgroup(mem)) {
+                mz = mem_cgroup_zoneinfo(mem, nid, zid);
+                excess = res_counter_soft_limit_excess(&mem->res);
+                /*
+                 * We have to update the tree if mz is on RB-tree or
+                 * mem is over its softlimit.
+                 */
+                if (excess || mz->on_tree) {
+                        spin_lock(&mctz->lock);
+                        /* if on-tree, remove it */
+                        if (mz->on_tree)
+                                __mem_cgroup_remove_exceeded(mem, mz, mctz);
+                        /*
+                         * Insert again. mz->usage_in_excess will be updated.
+                         * If excess is 0, no tree ops.
+                         */
+                        __mem_cgroup_insert_exceeded(mem, mz, mctz, excess);
+                        spin_unlock(&mctz->lock);
+                }
         }
 }
 
@@ -447,9 +442,10 @@ static struct mem_cgroup_per_zone *
 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
 {
         struct rb_node *rightmost = NULL;
-        struct mem_cgroup_per_zone *mz = NULL;
+        struct mem_cgroup_per_zone *mz;
 
 retry:
+        mz = NULL;
         rightmost = rb_last(&mctz->rb_root);
         if (!rightmost)
                 goto done;              /* Nothing to reclaim from */
@@ -1270,9 +1266,9 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
                         gfp_t gfp_mask, struct mem_cgroup **memcg,
                         bool oom, struct page *page)
 {
-        struct mem_cgroup *mem, *mem_over_limit, *mem_over_soft_limit;
+        struct mem_cgroup *mem, *mem_over_limit;
         int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
-        struct res_counter *fail_res, *soft_fail_res = NULL;
+        struct res_counter *fail_res;
 
         if (unlikely(test_thread_flag(TIF_MEMDIE))) {
                 /* Don't account this! */
@@ -1304,17 +1300,16 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
 
                 if (mem_cgroup_is_root(mem))
                         goto done;
-                ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res,
-                                                &soft_fail_res);
+                ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res);
                 if (likely(!ret)) {
                         if (!do_swap_account)
                                 break;
                         ret = res_counter_charge(&mem->memsw, PAGE_SIZE,
-                                                        &fail_res, NULL);
+                                                        &fail_res);
                         if (likely(!ret))
                                 break;
                         /* mem+swap counter fails */
-                        res_counter_uncharge(&mem->res, PAGE_SIZE, NULL);
+                        res_counter_uncharge(&mem->res, PAGE_SIZE);
                         flags |= MEM_CGROUP_RECLAIM_NOSWAP;
                         mem_over_limit = mem_cgroup_from_res_counter(fail_res,
                                                                         memsw);
@@ -1353,16 +1348,11 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
                 }
         }
         /*
-         * Insert just the ancestor, we should trickle down to the correct
-         * cgroup for reclaim, since the other nodes will be below their
-         * soft limit
+         * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
+         * if they exceeds softlimit.
          */
-        if (soft_fail_res) {
-                mem_over_soft_limit =
-                        mem_cgroup_from_res_counter(soft_fail_res, res);
-                if (mem_cgroup_soft_limit_check(mem_over_soft_limit))
-                        mem_cgroup_update_tree(mem_over_soft_limit, page);
-        }
+        if (mem_cgroup_soft_limit_check(mem))
+                mem_cgroup_update_tree(mem, page);
 done:
         return 0;
 nomem:
@@ -1437,10 +1427,9 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
         if (unlikely(PageCgroupUsed(pc))) {
                 unlock_page_cgroup(pc);
                 if (!mem_cgroup_is_root(mem)) {
-                        res_counter_uncharge(&mem->res, PAGE_SIZE, NULL);
+                        res_counter_uncharge(&mem->res, PAGE_SIZE);
                         if (do_swap_account)
-                                res_counter_uncharge(&mem->memsw, PAGE_SIZE,
-                                                        NULL);
+                                res_counter_uncharge(&mem->memsw, PAGE_SIZE);
                 }
                 css_put(&mem->css);
                 return;
@@ -1519,7 +1508,7 @@ static int mem_cgroup_move_account(struct page_cgroup *pc,
                 goto out;
 
         if (!mem_cgroup_is_root(from))
-                res_counter_uncharge(&from->res, PAGE_SIZE, NULL);
+                res_counter_uncharge(&from->res, PAGE_SIZE);
         mem_cgroup_charge_statistics(from, pc, false);
 
         page = pc->page;
@@ -1539,7 +1528,7 @@ static int mem_cgroup_move_account(struct page_cgroup *pc,
         }
 
         if (do_swap_account && !mem_cgroup_is_root(from))
-                res_counter_uncharge(&from->memsw, PAGE_SIZE, NULL);
+                res_counter_uncharge(&from->memsw, PAGE_SIZE);
         css_put(&from->css);
 
         css_get(&to->css);
@@ -1610,9 +1599,9 @@ uncharge:
         css_put(&parent->css);
         /* uncharge if move fails */
         if (!mem_cgroup_is_root(parent)) {
-                res_counter_uncharge(&parent->res, PAGE_SIZE, NULL);
+                res_counter_uncharge(&parent->res, PAGE_SIZE);
                 if (do_swap_account)
-                        res_counter_uncharge(&parent->memsw, PAGE_SIZE, NULL);
+                        res_counter_uncharge(&parent->memsw, PAGE_SIZE);
         }
         return ret;
 }
@@ -1803,8 +1792,7 @@ __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
                          * calling css_tryget
                          */
                         if (!mem_cgroup_is_root(memcg))
-                                res_counter_uncharge(&memcg->memsw, PAGE_SIZE,
-                                                        NULL);
+                                res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
                         mem_cgroup_swap_statistics(memcg, false);
                         mem_cgroup_put(memcg);
                 }
@@ -1831,9 +1819,9 @@ void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
         if (!mem)
                 return;
         if (!mem_cgroup_is_root(mem)) {
-                res_counter_uncharge(&mem->res, PAGE_SIZE, NULL);
+                res_counter_uncharge(&mem->res, PAGE_SIZE);
                 if (do_swap_account)
-                        res_counter_uncharge(&mem->memsw, PAGE_SIZE, NULL);
+                        res_counter_uncharge(&mem->memsw, PAGE_SIZE);
         }
         css_put(&mem->css);
 }
@@ -1848,7 +1836,6 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
         struct page_cgroup *pc;
         struct mem_cgroup *mem = NULL;
         struct mem_cgroup_per_zone *mz;
-        bool soft_limit_excess = false;
 
         if (mem_cgroup_disabled())
                 return NULL;
@@ -1888,10 +1875,10 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
         }
 
         if (!mem_cgroup_is_root(mem)) {
-                res_counter_uncharge(&mem->res, PAGE_SIZE, &soft_limit_excess);
+                res_counter_uncharge(&mem->res, PAGE_SIZE);
                 if (do_swap_account &&
                                 (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
-                        res_counter_uncharge(&mem->memsw, PAGE_SIZE, NULL);
+                        res_counter_uncharge(&mem->memsw, PAGE_SIZE);
         }
         if (ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
                 mem_cgroup_swap_statistics(mem, true);
@@ -1908,7 +1895,7 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
         mz = page_cgroup_zoneinfo(pc);
         unlock_page_cgroup(pc);
 
-        if (soft_limit_excess && mem_cgroup_soft_limit_check(mem))
+        if (mem_cgroup_soft_limit_check(mem))
                 mem_cgroup_update_tree(mem, page);
         /* at swapout, this memcg will be accessed to record to swap */
         if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
@@ -1986,7 +1973,7 @@ void mem_cgroup_uncharge_swap(swp_entry_t ent)
                  * This memcg can be obsolete one. We avoid calling css_tryget
                  */
                 if (!mem_cgroup_is_root(memcg))
-                        res_counter_uncharge(&memcg->memsw, PAGE_SIZE, NULL);
+                        res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
                 mem_cgroup_swap_statistics(memcg, false);
                 mem_cgroup_put(memcg);
         }
@@ -2233,6 +2220,7 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
         unsigned long reclaimed;
         int loop = 0;
         struct mem_cgroup_tree_per_zone *mctz;
+        unsigned long long excess;
 
         if (order > 0)
                 return 0;
@@ -2284,9 +2272,8 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
                                         break;
                         } while (1);
                 }
-                mz->usage_in_excess =
-                        res_counter_soft_limit_excess(&mz->mem->res);
                 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
+                excess = res_counter_soft_limit_excess(&mz->mem->res);
                 /*
                  * One school of thought says that we should not add
                  * back the node to the tree if reclaim returns 0.
@@ -2295,8 +2282,8 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
                  * memory to reclaim from. Consider this as a longer
                  * term TODO.
                  */
-                if (mz->usage_in_excess)
-                        __mem_cgroup_insert_exceeded(mz->mem, mz, mctz);
+                /* If excess == 0, no tree ops */
+                __mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);
                 spin_unlock(&mctz->lock);
                 css_put(&mz->mem->css);
                 loop++;
diff --git a/mm/mmap.c b/mm/mmap.c
index 21d4029a07b3..73f5e4b64010 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2282,7 +2282,7 @@ static void special_mapping_close(struct vm_area_struct *vma)
 {
 }
 
-static struct vm_operations_struct special_mapping_vmops = {
+static const struct vm_operations_struct special_mapping_vmops = {
         .close = special_mapping_close,
         .fault = special_mapping_fault,
 };
diff --git a/mm/nommu.c b/mm/nommu.c
index c73aa4753d79..5189b5aed8c0 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -79,7 +79,7 @@ static struct kmem_cache *vm_region_jar;
 struct rb_root nommu_region_tree = RB_ROOT;
 DECLARE_RWSEM(nommu_region_sem);
 
-struct vm_operations_struct generic_file_vm_ops = {
+const struct vm_operations_struct generic_file_vm_ops = {
 };
 
 /*
diff --git a/mm/percpu.c b/mm/percpu.c
index 43d8cacfdaa5..4a048abad043 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1043,7 +1043,9 @@ static struct pcpu_chunk *alloc_pcpu_chunk(void)
  */
 static void *pcpu_alloc(size_t size, size_t align, bool reserved)
 {
+        static int warn_limit = 10;
         struct pcpu_chunk *chunk;
+        const char *err;
         int slot, off;
 
         if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
@@ -1059,11 +1061,14 @@ static void *pcpu_alloc(size_t size, size_t align, bool reserved)
         if (reserved && pcpu_reserved_chunk) {
                 chunk = pcpu_reserved_chunk;
                 if (size > chunk->contig_hint ||
-                    pcpu_extend_area_map(chunk) < 0)
+                    pcpu_extend_area_map(chunk) < 0) {
+                        err = "failed to extend area map of reserved chunk";
                         goto fail_unlock;
+                }
                 off = pcpu_alloc_area(chunk, size, align);
                 if (off >= 0)
                         goto area_found;
+                err = "alloc from reserved chunk failed";
                 goto fail_unlock;
         }
 
@@ -1080,6 +1085,7 @@ restart:
                         case 1:
                                 goto restart;   /* pcpu_lock dropped, restart */
                         default:
+                                err = "failed to extend area map";
                                 goto fail_unlock;
                         }
 
@@ -1093,8 +1099,10 @@ restart:
         spin_unlock_irq(&pcpu_lock);
 
         chunk = alloc_pcpu_chunk();
-        if (!chunk)
+        if (!chunk) {
+                err = "failed to allocate new chunk";
                 goto fail_unlock_mutex;
+        }
 
         spin_lock_irq(&pcpu_lock);
         pcpu_chunk_relocate(chunk, -1);
@@ -1107,6 +1115,7 @@ area_found:
         if (pcpu_populate_chunk(chunk, off, size)) {
                 spin_lock_irq(&pcpu_lock);
                 pcpu_free_area(chunk, off);
+                err = "failed to populate";
                 goto fail_unlock;
         }
 
@@ -1119,6 +1128,13 @@ fail_unlock:
         spin_unlock_irq(&pcpu_lock);
 fail_unlock_mutex:
         mutex_unlock(&pcpu_alloc_mutex);
+        if (warn_limit) {
+                pr_warning("PERCPU: allocation failed, size=%zu align=%zu, "
+                           "%s\n", size, align, err);
+                dump_stack();
+                if (!--warn_limit)
+                        pr_info("PERCPU: limit reached, disable warning\n");
+        }
         return NULL;
 }
 
@@ -1347,6 +1363,10 @@ struct pcpu_alloc_info * __init pcpu_build_alloc_info(
         struct pcpu_alloc_info *ai;
         unsigned int *cpu_map;
 
+        /* this function may be called multiple times */
+        memset(group_map, 0, sizeof(group_map));
+        memset(group_cnt, 0, sizeof(group_map));
+
         /*
          * Determine min_unit_size, alloc_size and max_upa such that
          * alloc_size is multiple of atom_size and is the smallest
@@ -1574,6 +1594,7 @@ static void pcpu_dump_alloc_info(const char *lvl,
 int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
                                   void *base_addr)
 {
+        static char cpus_buf[4096] __initdata;
         static int smap[2], dmap[2];
         size_t dyn_size = ai->dyn_size;
         size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
@@ -1585,17 +1606,26 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
         int *unit_map;
         int group, unit, i;
 
+        cpumask_scnprintf(cpus_buf, sizeof(cpus_buf), cpu_possible_mask);
+
+#define PCPU_SETUP_BUG_ON(cond) do {                                    \
+        if (unlikely(cond)) {                                           \
+                pr_emerg("PERCPU: failed to initialize, %s", #cond);    \
+                pr_emerg("PERCPU: cpu_possible_mask=%s\n", cpus_buf);   \
+                pcpu_dump_alloc_info(KERN_EMERG, ai);                   \
+                BUG();                                                  \
+        }                                                               \
+} while (0)
+
         /* sanity checks */
         BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC ||
                      ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC);
-        BUG_ON(ai->nr_groups <= 0);
-        BUG_ON(!ai->static_size);
-        BUG_ON(!base_addr);
-        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);
+        PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
+        PCPU_SETUP_BUG_ON(!ai->static_size);
+        PCPU_SETUP_BUG_ON(!base_addr);
+        PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
+        PCPU_SETUP_BUG_ON(ai->unit_size & ~PAGE_MASK);
+        PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
 
         /* process group information and build config tables accordingly */
         group_offsets = alloc_bootmem(ai->nr_groups * sizeof(group_offsets[0]));
@@ -1604,7 +1634,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
         unit_off = alloc_bootmem(nr_cpu_ids * sizeof(unit_off[0]));
 
         for (cpu = 0; cpu < nr_cpu_ids; cpu++)
-                unit_map[cpu] = NR_CPUS;
+                unit_map[cpu] = UINT_MAX;
         pcpu_first_unit_cpu = NR_CPUS;
 
         for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
@@ -1618,8 +1648,9 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
                         if (cpu == NR_CPUS)
                                 continue;
 
-                        BUG_ON(cpu > nr_cpu_ids || !cpu_possible(cpu));
-                        BUG_ON(unit_map[cpu] != NR_CPUS);
+                        PCPU_SETUP_BUG_ON(cpu > nr_cpu_ids);
+                        PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
+                        PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);
 
                         unit_map[cpu] = unit + i;
                         unit_off[cpu] = gi->base_offset + i * ai->unit_size;
@@ -1632,7 +1663,11 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
         pcpu_nr_units = unit;
 
         for_each_possible_cpu(cpu)
-                BUG_ON(unit_map[cpu] == NR_CPUS);
+                PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX);
+
+        /* we're done parsing the input, undefine BUG macro and dump config */
+#undef PCPU_SETUP_BUG_ON
+        pcpu_dump_alloc_info(KERN_INFO, ai);
 
         pcpu_nr_groups = ai->nr_groups;
         pcpu_group_offsets = group_offsets;
@@ -1782,7 +1817,7 @@ int __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size,
         void *base = (void *)ULONG_MAX;
         void **areas = NULL;
         struct pcpu_alloc_info *ai;
-        size_t size_sum, areas_size;
+        size_t size_sum, areas_size, max_distance;
         int group, i, rc;
 
         ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
@@ -1832,8 +1867,24 @@ int __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size,
         }
 
         /* base address is now known, determine group base offsets */
-        for (group = 0; group < ai->nr_groups; group++)
+        max_distance = 0;
+        for (group = 0; group < ai->nr_groups; group++) {
                 ai->groups[group].base_offset = areas[group] - base;
+                max_distance = max(max_distance, ai->groups[group].base_offset);
+        }
+        max_distance += ai->unit_size;
+
+        /* warn if maximum distance is further than 75% of vmalloc space */
+        if (max_distance > (VMALLOC_END - VMALLOC_START) * 3 / 4) {
+                pr_warning("PERCPU: max_distance=0x%lx too large for vmalloc "
+                           "space 0x%lx\n",
+                           max_distance, VMALLOC_END - VMALLOC_START);
+#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
+                /* and fail if we have fallback */
+                rc = -EINVAL;
+                goto out_free;
+#endif
+        }
 
         pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
                 PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size,
diff --git a/mm/rmap.c b/mm/rmap.c
index 28aafe2b5306..dd43373a483f 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -242,8 +242,8 @@ vma_address(struct page *page, struct vm_area_struct *vma)
 }
 
 /*
- * At what user virtual address is page expected in vma? checking that the
- * page matches the vma: currently only used on anon pages, by unuse_vma;
+ * At what user virtual address is page expected in vma?
+ * checking that the page matches the vma.
  */
 unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
 {
diff --git a/mm/shmem.c b/mm/shmem.c
index ccf446a9faa1..356dd99566ec 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -218,7 +218,7 @@ static const struct file_operations shmem_file_operations;
 static const struct inode_operations shmem_inode_operations;
 static const struct inode_operations shmem_dir_inode_operations;
 static const struct inode_operations shmem_special_inode_operations;
-static struct vm_operations_struct shmem_vm_ops;
+static const struct vm_operations_struct shmem_vm_ops;
 
 static struct backing_dev_info shmem_backing_dev_info  __read_mostly = {
         .ra_pages       = 0,    /* No readahead */
@@ -2498,7 +2498,7 @@ static const struct super_operations shmem_ops = {
         .put_super      = shmem_put_super,
 };
 
-static struct vm_operations_struct shmem_vm_ops = {
+static const struct vm_operations_struct shmem_vm_ops = {
         .fault          = shmem_fault,
 #ifdef CONFIG_NUMA
         .set_policy     = shmem_set_policy,