2 files changed, 28 insertions, 131 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index f7ac27215512..869d7d301448 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -156,10 +156,6 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK
 config NEED_PER_CPU_PAGE_FIRST_CHUNK
         def_bool y
 
-config NEED_PER_CPU_LPAGE_FIRST_CHUNK
-        def_bool y
-        depends on NEED_MULTIPLE_NODES
-
 config HAVE_CPUMASK_OF_CPU_MAP
         def_bool X86_64_SMP
 
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index 67f6314de9f1..d559af913e1f 100644
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -55,6 +55,7 @@ EXPORT_SYMBOL(__per_cpu_offset);
 #define PERCPU_FIRST_CHUNK_RESERVE      0
 #endif
 
+#ifdef CONFIG_X86_32
 /**
  * pcpu_need_numa - determine percpu allocation needs to consider NUMA
  *
@@ -83,6 +84,7 @@ static bool __init pcpu_need_numa(void)
 #endif
         return false;
 }
+#endif
 
 /**
  * pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu
@@ -136,128 +138,23 @@ static void __init pcpu_fc_free(void *ptr, size_t size)
         free_bootmem(__pa(ptr), size);
 }
 
-/*
- * Large page remapping allocator
- */
-#ifdef CONFIG_NEED_MULTIPLE_NODES
-static void __init pcpul_map(void *ptr, size_t size, void *addr)
-{
-        pmd_t *pmd, pmd_v;
-
-        pmd = populate_extra_pmd((unsigned long)addr);
-        pmd_v = pfn_pmd(page_to_pfn(virt_to_page(ptr)), PAGE_KERNEL_LARGE);
-        set_pmd(pmd, pmd_v);
-}
-
-static int pcpu_lpage_cpu_distance(unsigned int from, unsigned int to)
+static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
 {
+#ifdef CONFIG_NEED_MULTIPLE_NODES
         if (early_cpu_to_node(from) == early_cpu_to_node(to))
                 return LOCAL_DISTANCE;
         else
                 return REMOTE_DISTANCE;
-}
-
-static int __init setup_pcpu_lpage(bool chosen)
-{
-        size_t reserve = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE;
-        size_t dyn_size = reserve - PERCPU_FIRST_CHUNK_RESERVE;
-        struct pcpu_alloc_info *ai;
-        int rc;
-
-        /* on non-NUMA, embedding is better */
-        if (!chosen && !pcpu_need_numa())
-                return -EINVAL;
-
-        /* need PSE */
-        if (!cpu_has_pse) {
-                pr_warning("PERCPU: lpage allocator requires PSE\n");
-                return -EINVAL;
-        }
-
-        /* allocate and build unit_map */
-        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);
-        }
-
-        /* do the parameters look okay? */
-        if (!chosen) {
-                size_t vm_size = VMALLOC_END - VMALLOC_START;
-                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) {
-                        pr_info("PERCPU: too large chunk size %zuMB for "
-                                "large page remap\n", tot_size >> 20);
-                        rc = -EINVAL;
-                        goto out_free;
-                }
-        }
-
-        rc = pcpu_lpage_first_chunk(ai, pcpu_fc_alloc, pcpu_fc_free, pcpul_map);
-out_free:
-        pcpu_free_alloc_info(ai);
-        return rc;
-}
 #else
-static int __init setup_pcpu_lpage(bool chosen)
-{
-        return -EINVAL;
-}
+        return LOCAL_DISTANCE;
 #endif
-
-/*
- * Embedding allocator
- *
- * The first chunk is sized to just contain the static area plus
- * module and dynamic reserves and embedded into linear physical
- * mapping so that it can use PMD mapping without additional TLB
- * pressure.
- */
-static int __init setup_pcpu_embed(bool chosen)
-{
-        size_t reserve = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE;
-
-        /*
-         * If large page isn't supported, there's no benefit in doing
-         * this.  Also, embedding allocation doesn't play well with
-         * NUMA.
-         */
-        if (!chosen && (!cpu_has_pse || pcpu_need_numa()))
-                return -EINVAL;
-
-        return pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
-                                      reserve - PERCPU_FIRST_CHUNK_RESERVE,
-                                      PAGE_SIZE, NULL, pcpu_fc_alloc,
-                                      pcpu_fc_free);
 }
 
-/*
- * Page allocator
- *
- * Boring fallback 4k page allocator.  This allocator puts more
- * pressure on PTE TLBs but other than that behaves nicely on both UMA
- * and NUMA.
- */
 static void __init pcpup_populate_pte(unsigned long addr)
 {
         populate_extra_pte(addr);
 }
 
-static int __init setup_pcpu_page(void)
-{
-        return pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
-                                     pcpu_fc_alloc, pcpu_fc_free,
-                                     pcpup_populate_pte);
-}
-
 static inline void setup_percpu_segment(int cpu)
 {
 #ifdef CONFIG_X86_32
@@ -281,30 +178,34 @@ void __init setup_per_cpu_areas(void)
                 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
 
         /*
-         * Allocate percpu area.  If PSE is supported, try to make use
-         * of large page mappings.  Please read comments on top of
-         * each allocator for details.
+         * Allocate percpu area.  Embedding allocator is our favorite;
+         * however, on NUMA configurations, it can result in very
+         * sparse unit mapping and vmalloc area isn't spacious enough
+         * on 32bit.  Use page in that case.
          */
+#ifdef CONFIG_X86_32
+        if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa())
+                pcpu_chosen_fc = PCPU_FC_PAGE;
+#endif
         rc = -EINVAL;
-        if (pcpu_chosen_fc != PCPU_FC_AUTO) {
-                if (pcpu_chosen_fc != PCPU_FC_PAGE) {
-                        if (pcpu_chosen_fc == PCPU_FC_LPAGE)
-                                rc = setup_pcpu_lpage(true);
-                        else
-                                rc = setup_pcpu_embed(true);
-
-                        if (rc < 0)
-                                pr_warning("PERCPU: %s allocator failed (%d), "
-                                           "falling back to page size\n",
-                                           pcpu_fc_names[pcpu_chosen_fc], rc);
-                }
-        } else {
-                rc = setup_pcpu_lpage(false);
+        if (pcpu_chosen_fc != PCPU_FC_PAGE) {
+                const size_t atom_size = cpu_has_pse ? PMD_SIZE : PAGE_SIZE;
+                const size_t dyn_size = PERCPU_MODULE_RESERVE +
+                        PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE;
+
+                rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
+                                            dyn_size, atom_size,
+                                            pcpu_cpu_distance,
+                                            pcpu_fc_alloc, pcpu_fc_free);
                 if (rc < 0)
-                        rc = setup_pcpu_embed(false);
+                        pr_warning("PERCPU: %s allocator failed (%d), "
+                                   "falling back to page size\n",
+                                   pcpu_fc_names[pcpu_chosen_fc], rc);
         }
         if (rc < 0)
-                rc = setup_pcpu_page();
+                rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
+                                           pcpu_fc_alloc, pcpu_fc_free,
+                                           pcpup_populate_pte);
         if (rc < 0)
                 panic("cannot initialize percpu area (err=%d)", rc);