mm/vmalloc.c: remove dead code in vb_alloc

Space in a vmap block that was once allocated is considered dirty and
not made available for allocation again before the whole block is
recycled.  The result is that free space within a vmap block is always
contiguous.

So if a vmap block has enough free space for allocation, the allocation
is impossible to fail.  Thus, the fragmented block purging was never
invoked from vb_alloc().  So remove this dead code.

[ Same patches also sent by:

    Chanho Min <chanho.min@lge.com>
    Johannes Weiner <hannes@cmpxchg.org>

  but git doesn't do "multiple authors" ]

Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 15 deletions

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 96b77a982545..a35f4f5bb908 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -910,7 +910,6 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
         struct vmap_block *vb;
         unsigned long addr = 0;
         unsigned int order;
-        int purge = 0;
 
         BUG_ON(size & ~PAGE_MASK);
         BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
@@ -934,17 +933,7 @@ again:
                 if (vb->free < 1UL << order)
                         goto next;
 
-                i = bitmap_find_free_region(vb->alloc_map,
-                                                VMAP_BBMAP_BITS, order);
-
-                if (i < 0) {
-                        if (vb->free + vb->dirty == VMAP_BBMAP_BITS) {
-                                /* fragmented and no outstanding allocations */
-                                BUG_ON(vb->dirty != VMAP_BBMAP_BITS);
-                                purge = 1;
-                        }
-                        goto next;
-                }
+                i = VMAP_BBMAP_BITS - vb->free;
                 addr = vb->va->va_start + (i << PAGE_SHIFT);
                 BUG_ON(addr_to_vb_idx(addr) !=
                                 addr_to_vb_idx(vb->va->va_start));
@@ -960,9 +949,6 @@ next:
                 spin_unlock(&vb->lock);
         }
 
-        if (purge)
-                purge_fragmented_blocks_thiscpu();
-
         put_cpu_var(vmap_block_queue);
         rcu_read_unlock();