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Message-ID: <Zs/+hbsyBVHUgoYl@mev-dev.igk.intel.com>
Date: Thu, 29 Aug 2024 06:52:21 +0200
From: Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>
To: Michael Chan <michael.chan@...adcom.com>
Cc: davem@...emloft.net, netdev@...r.kernel.org, edumazet@...gle.com,
kuba@...nel.org, pabeni@...hat.com, pavan.chebbi@...adcom.com,
andrew.gospodarek@...adcom.com, horms@...nel.org,
helgaas@...nel.org, przemyslaw.kitszel@...el.com,
Hongguang Gao <hongguang.gao@...adcom.com>,
Somnath Kotur <somnath.kotur@...adcom.com>
Subject: Re: [PATCH net-next v4 9/9] bnxt_en: Support dynamic MSIX
On Wed, Aug 28, 2024 at 11:32:35AM -0700, Michael Chan wrote:
> A range of MSIX vectors are allocated at initialization for the number
> needed for RocE and L2. During run-time, if the user increases or
> decreases the number of L2 rings, all the MSIX vectors have to be
> freed and a new range has to be allocated. This is not optimal and
> causes disruptions to RoCE traffic every time there is a change in L2
> MSIX.
>
> If the system supports dynamic MSIX allocations, use dynamic
> allocation to add new L2 MSIX vectors or free unneeded L2 MSIX
> vectors. RoCE traffic is not affected using this scheme.
>
> Reviewed-by: Hongguang Gao <hongguang.gao@...adcom.com>
> Reviewed-by: Somnath Kotur <somnath.kotur@...adcom.com>
> Reviewed-by: Simon Horman <horms@...nel.org>
> Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@...el.com>
> Signed-off-by: Michael Chan <michael.chan@...adcom.com>
> ---
> Cc: Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>
> v4: Simplify adding and deleting MSIX
> v2: Fix typo in changelog
> ---
> drivers/net/ethernet/broadcom/bnxt/bnxt.c | 37 +++++++++++++++++++++--
> 1 file changed, 34 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> index fa4115f6dafe..c9248ed9330c 100644
> --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> @@ -10622,6 +10622,30 @@ static void bnxt_setup_msix(struct bnxt *bp)
>
> static int bnxt_init_int_mode(struct bnxt *bp);
>
> +static int bnxt_change_msix(struct bnxt *bp, int total)
> +{
> + struct msi_map map;
> + int i;
> +
> + /* add MSIX to the end if needed */
> + for (i = bp->total_irqs; i < total; i++) {
> + map = pci_msix_alloc_irq_at(bp->pdev, i, NULL);
> + if (map.index < 0)
> + return bp->total_irqs;
> + bp->irq_tbl[i].vector = map.virq;
> + bp->total_irqs++;
> + }
> +
> + /* trim MSIX from the end if needed */
> + for (i = bp->total_irqs; i > total; i--) {
> + map.index = i - 1;
> + map.virq = bp->irq_tbl[i - 1].vector;
> + pci_msix_free_irq(bp->pdev, map);
> + bp->total_irqs--;
> + }
> + return bp->total_irqs;
> +}
> +
> static int bnxt_setup_int_mode(struct bnxt *bp)
> {
> int rc;
> @@ -10788,6 +10812,7 @@ static void bnxt_clear_int_mode(struct bnxt *bp)
> int bnxt_reserve_rings(struct bnxt *bp, bool irq_re_init)
> {
> bool irq_cleared = false;
> + bool irq_change = false;
> int tcs = bp->num_tc;
> int irqs_required;
> int rc;
> @@ -10806,15 +10831,21 @@ int bnxt_reserve_rings(struct bnxt *bp, bool irq_re_init)
> }
>
> if (irq_re_init && BNXT_NEW_RM(bp) && irqs_required != bp->total_irqs) {
> - bnxt_ulp_irq_stop(bp);
> - bnxt_clear_int_mode(bp);
> - irq_cleared = true;
> + irq_change = true;
> + if (!pci_msix_can_alloc_dyn(bp->pdev)) {
> + bnxt_ulp_irq_stop(bp);
> + bnxt_clear_int_mode(bp);
> + irq_cleared = true;
> + }
> }
> rc = __bnxt_reserve_rings(bp);
> if (irq_cleared) {
> if (!rc)
> rc = bnxt_init_int_mode(bp);
> bnxt_ulp_irq_restart(bp, rc);
> + } else if (irq_change && !rc) {
> + if (bnxt_change_msix(bp, irqs_required) != irqs_required)
> + rc = -ENOSPC;
> }
> if (rc) {
> netdev_err(bp->dev, "ring reservation/IRQ init failure rc: %d\n", rc);
> --
> 2.30.1
Thanks,
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>
>
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