Re: [dpdk-dev] [PATCH 1/2] mempool/octeontx2: fix shift calculation

[Jerin Jacob <jerinjacobk@gmail.com>]

On Tue, Jun 15, 2021 at 12:54 AM <pbhagavatula@marvell.com> wrote:
>
> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>
> Shift is used to generate an 8-bit saturate value from the current
> aura used count. The shift value should be derived from the log2 of
> block count if it is greater than 256 else the shift should be 0.
>
> Fixes: 7bcc47cbe2fa ("mempool/octeontx2: add mempool alloc op")

Cc: stable@dpdk.og

>
> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>

Series applied to dpdk-next-net-eventdev/for-main. Thanks


> ---
>  drivers/mempool/octeontx2/otx2_mempool_ops.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mempool/octeontx2/otx2_mempool_ops.c b/drivers/mempool/octeontx2/otx2_mempool_ops.c
> index 9ff71bcf6b..d827fd8c7b 100644
> --- a/drivers/mempool/octeontx2/otx2_mempool_ops.c
> +++ b/drivers/mempool/octeontx2/otx2_mempool_ops.c
> @@ -611,7 +611,8 @@ npa_lf_aura_pool_pair_alloc(struct otx2_npa_lf *lf, const uint32_t block_size,
>         /* Update aura fields */
>         aura->pool_addr = pool_id;/* AF will translate to associated poolctx */
>         aura->ena = 1;
> -       aura->shift = __builtin_clz(block_count) - 8;
> +       aura->shift = rte_log2_u32(block_count);
> +       aura->shift = aura->shift < 8 ? 0 : aura->shift - 8;
>         aura->limit = block_count;
>         aura->pool_caching = 1;
>         aura->err_int_ena = BIT(NPA_AURA_ERR_INT_AURA_ADD_OVER);
> @@ -626,7 +627,8 @@ npa_lf_aura_pool_pair_alloc(struct otx2_npa_lf *lf, const uint32_t block_size,
>         pool->ena = 1;
>         pool->buf_size = block_size / OTX2_ALIGN;
>         pool->stack_max_pages = stack_size;
> -       pool->shift = __builtin_clz(block_count) - 8;
> +       pool->shift = rte_log2_u32(block_count);
> +       pool->shift = pool->shift < 8 ? 0 : pool->shift - 8;
>         pool->ptr_start = 0;
>         pool->ptr_end = ~0;
>         pool->stack_caching = 1;
> --
> 2.17.1
>