On 5/30/2018 1:50 PM, Eric Dumazet wrote:
On Wed, May 30, 2018 at 4:30 PM Qing Huang <qing.huang@xxxxxxxxxx> wrote:
On 5/29/2018 9:11 PM, Eric Dumazet wrote:
Commit 1383cb8103bb ("mlx4_core: allocate ICM memory in page size chunks")
brought a regression caught in our regression suite, thanks to KASAN.
If KASAN reported issue was really caused by smaller chunk sizes,
changing allocation
order dynamically will eventually hit the same issue.
Sigh, you have little idea of what your patch really did...
The KASAN part only shows the tip of the iceberg, but our main concern
is an increase of memory overhead.
Well, the commit log only mentioned KASAN and but the change here didn't
seem to solve
the issue.
Alternative is to revert your patch, since we are now very late in 4.17 cycle.
Memory usage has grown a lot with your patch, since each 4KB page needs a full
struct mlx4_icm_chunk (256 bytes of overhead !)
Going to smaller chunks will have some overhead. It depends on the
application though.
What's the total increased memory consumption in your env?
Really we have no choice here, your patch went too far and increased
memory consumption quite a lot.
My patch is simply the best way to address your original concern, and
not increase overall overhead.
( each struct mlx4_icm_chunk should be able to store
MLX4_ICM_CHUNK_LEN pages, instead of one page of 4KB )
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