mm/percpu.c: optimize the code in pcpu_setup_first_chunk() a little bit

[linux-block.git] / mm / percpu.c

diff --git a/mm/percpu.c b/mm/percpu.c
index 93b1bec2b28d264c46c40b7f09cec54c00049c2a..ab4ba2ac91c724747538d525bf4361fdfe3b23b4 100644 (file)
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -2581,14 +2581,12 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
 {
        size_t size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
        size_t static_size, dyn_size;
-       struct pcpu_chunk *chunk;
        unsigned long *group_offsets;
        size_t *group_sizes;
        unsigned long *unit_off;
        unsigned int cpu;
        int *unit_map;
        int group, unit, i;
-       int map_size;
        unsigned long tmp_addr;
        size_t alloc_size;
 
@@ -2697,7 +2695,7 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
        pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
        pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
        pcpu_atom_size = ai->atom_size;
-       pcpu_chunk_struct_size = struct_size(chunk, populated,
+       pcpu_chunk_struct_size = struct_size((struct pcpu_chunk *)0, populated,
                                             BITS_TO_LONGS(pcpu_unit_pages));
 
        pcpu_stats_save_ai(ai);
@@ -2734,29 +2732,23 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
        dyn_size = ai->dyn_size - (static_size - ai->static_size);
 
        /*
-        * Initialize first chunk.
-        * If the reserved_size is non-zero, this initializes the reserved
-        * chunk.  If the reserved_size is zero, the reserved chunk is NULL
-        * and the dynamic region is initialized here.  The first chunk,
-        * pcpu_first_chunk, will always point to the chunk that serves
-        * the dynamic region.
+        * Initialize first chunk:
+        * This chunk is broken up into 3 parts:
+        *              < static | [reserved] | dynamic >
+        * - static - there is no backing chunk because these allocations can
+        *   never be freed.
+        * - reserved (pcpu_reserved_chunk) - exists primarily to serve
+        *   allocations from module load.
+        * - dynamic (pcpu_first_chunk) - serves the dynamic part of the first
+        *   chunk.
         */
        tmp_addr = (unsigned long)base_addr + static_size;
-       map_size = ai->reserved_size ?: dyn_size;
-       chunk = pcpu_alloc_first_chunk(tmp_addr, map_size);
-
-       /* init dynamic chunk if necessary */
-       if (ai->reserved_size) {
-               pcpu_reserved_chunk = chunk;
-
-               tmp_addr = (unsigned long)base_addr + static_size +
-                          ai->reserved_size;
-               map_size = dyn_size;
-               chunk = pcpu_alloc_first_chunk(tmp_addr, map_size);
-       }
+       if (ai->reserved_size)
+               pcpu_reserved_chunk = pcpu_alloc_first_chunk(tmp_addr,
+                                               ai->reserved_size);
+       tmp_addr = (unsigned long)base_addr + static_size + ai->reserved_size;
+       pcpu_first_chunk = pcpu_alloc_first_chunk(tmp_addr, dyn_size);
 
-       /* link the first chunk in */
-       pcpu_first_chunk = chunk;
        pcpu_nr_empty_pop_pages = pcpu_first_chunk->nr_empty_pop_pages;
        pcpu_chunk_relocate(pcpu_first_chunk, -1);