[Mesa-dev] [PATCH 2/4] i965/drm: Round down buffer size and calculate the bucket index

[James Xiong]

From: "Xiong, James" <james.xiong at intel.com>

a buffer is now put in cached bucket #n when its size is between
bucket[n].size and bucket[n+1].size - 1

Signed-off-by: Xiong, James <james.xiong at intel.com>
---
 src/mesa/drivers/dri/i965/brw_bufmgr.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_bufmgr.c b/src/mesa/drivers/dri/i965/brw_bufmgr.c
index e68da26..6a9b005 100644
--- a/src/mesa/drivers/dri/i965/brw_bufmgr.c
+++ b/src/mesa/drivers/dri/i965/brw_bufmgr.c
@@ -189,8 +189,8 @@ bo_tile_pitch(struct brw_bufmgr *bufmgr, uint32_t pitch, uint32_t tiling)
 static struct bo_cache_bucket *
 bucket_for_size(struct brw_bufmgr *bufmgr, uint64_t size)
 {
-   /* Calculating the pages and rounding up to the page size. */
-   const unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
+   /* Calculating the pages and rounding down to the  page size. */
+   const unsigned pages = (size < PAGE_SIZE) ? 1 : size / PAGE_SIZE;
 
    /* Row  Bucket sizes    clz((x-1) | 3)   Row    Column
     *        in pages                      stride   size
@@ -211,8 +211,7 @@ bucket_for_size(struct brw_bufmgr *bufmgr, uint64_t size)
    int col_size_log2 = row - 1;
    col_size_log2 += (col_size_log2 < 0);
 
-   const unsigned col = (pages - prev_row_max_pages +
-                        ((1 << col_size_log2) - 1)) >> col_size_log2;
+   const unsigned col = (pages - prev_row_max_pages) >> col_size_log2;
 
    /* Calculating the index based on the row and column. */
    const unsigned index = (row * 4) + (col - 1);
@@ -1285,9 +1284,9 @@ add_bucket(struct brw_bufmgr *bufmgr, int size)
    bufmgr->cache_bucket[i].size = size;
    bufmgr->num_buckets++;
 
+   assert(bucket_for_size(bufmgr, size - 1) == &bufmgr->cache_bucket[i==0?0:i-1]);
    assert(bucket_for_size(bufmgr, size) == &bufmgr->cache_bucket[i]);
-   assert(bucket_for_size(bufmgr, size - 2048) == &bufmgr->cache_bucket[i]);
-   assert(bucket_for_size(bufmgr, size + 1) != &bufmgr->cache_bucket[i]);
+   assert(bucket_for_size(bufmgr, size + 1) == &bufmgr->cache_bucket[i]);
 }
 
 static void
-- 
2.7.4