diff mbox series

[4/5] octeontx2-af: Fix the size of memory allocated for the 'id_bmap' bitmap

Message ID ce2710771939065d68f95d86a27cf7cea7966365.1669378798.git.christophe.jaillet@wanadoo.fr
State New
Headers
Series octeontx2-af: Clean-up some bitmap related usage |

Commit Message

Christophe JAILLET Nov. 25, 2022, 12:24 p.m. UTC 
  This allocation is really spurious.
The size of the bitmap is 'tot_ids' and it is used as such in the driver.

So we could expect something like:
   table->id_bmap = devm_kcalloc(rvu->dev, BITS_TO_LONGS(table->tot_ids),
			         sizeof(long), GFP_KERNEL);

However, when the bitmap is allocated, we allocate:
   BITS_TO_LONGS(table->tot_ids) * table->tot_ids ~=
   table->tot_ids / 32 * table->tot_ids ~=
   table->tot_ids^2 / 32

It is proportional to the square of 'table->tot_ids' which seems to
potentially be big.

Allocate the expected amount of memory, and switch to the bitmap API to
have it more straightforward.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
This patch is speculative.

If I'm right, I'm curious to know if 'able->tot_ids' can really get big
(I'm just guessing) , and if yes, how much.
---
 drivers/net/ethernet/marvell/octeontx2/af/rvu_npc_hash.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_npc_hash.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_npc_hash.c
index 3f94b620ef5a..ae34746341c4 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_npc_hash.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_npc_hash.c
@@ -1914,8 +1914,8 @@  int rvu_npc_exact_init(struct rvu *rvu)
 	dev_dbg(rvu->dev, "%s: Allocated bitmap for 32 entry cam\n", __func__);
 
 	table->tot_ids = (table->mem_table.depth * table->mem_table.ways) + table->cam_table.depth;
-	table->id_bmap = devm_kcalloc(rvu->dev, BITS_TO_LONGS(table->tot_ids),
-				      table->tot_ids, GFP_KERNEL);
+	table->id_bmap = devm_bitmap_zalloc(rvu->dev, table->tot_ids,
+					    GFP_KERNEL);
 
 	if (!table->id_bmap)
 		return -ENOMEM;