From: Joe Damato <jdamato@fastly.com>
To: Jakub Kicinski <kuba@kernel.org>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
tariqt@nvidia.com, saeedm@nvidia.com, mkarsten@uwaterloo.ca,
gal@nvidia.com, nalramli@fastly.com,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
"open list:MELLANOX MLX4 core VPI driver"
<linux-rdma@vger.kernel.org>
Subject: Re: [PATCH net-next v2 1/3] net/mlx4: Track RX allocation failures in a stat
Date: Fri, 26 Apr 2024 17:28:03 -0700 [thread overview]
Message-ID: <ZixGk8dy8INWD6PV@LQ3V64L9R2> (raw)
In-Reply-To: <20240426165213.298d8409@kernel.org>
On Fri, Apr 26, 2024 at 04:52:13PM -0700, Jakub Kicinski wrote:
> On Fri, 26 Apr 2024 16:43:53 -0700 Joe Damato wrote:
> > > In case of mlx4 looks like the buffer refill is "async", the driver
> > > tries to refill the buffers to max, but if it fails the next NAPI poll
> > > will try again. Allocation failures are not directly tied to packet
> > > drops. In case of bnxt if "replacement" buffer can't be allocated -
> > > packet is dropped and old buffer gets returned to the ring (although
> > > if I'm 100% honest bnxt may be off by a couple, too, as the OOM stat
> > > gets incremented on ifup pre-fill failures).
> >
> > Yes, I see that now. I'll drop this patch entirely from v3 and just leave
> > the other two and remove alloc_fail from the queue stats patch.
>
> Up to you, but I'd keep alloc_fail itself.
> If mlx4 gets page pool support one day it will be useful to run this:
> https://lore.kernel.org/all/20240426232400.624864-1-kuba@kernel.org/
>
> And I think it's useful to be able to check in case there are Rx
> discards whether the system was also under transient memory pressure
> or not.
Ah, maybe I read what you wrote incorrectly in your previous message.
I think you were saying that I should drop just the
dev->stats.rx_missed_errors = dropped;
due to the definition of rx_missed_errors, but that by the definition of
rx-alloc-fail:
alloc_fail = ring->dropped;
is still valid and can stay.
Is that right or am I just totally off?
next prev parent reply other threads:[~2024-04-27 0:28 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-26 18:33 [PATCH net-next v2 0/3] mlx4: Add support for netdev-genl API Joe Damato
2024-04-26 18:33 ` [PATCH net-next v2 1/3] net/mlx4: Track RX allocation failures in a stat Joe Damato
2024-04-26 20:00 ` Jakub Kicinski
2024-04-26 23:43 ` Joe Damato
2024-04-26 23:52 ` Jakub Kicinski
2024-04-27 0:28 ` Joe Damato [this message]
2024-04-27 0:34 ` Jakub Kicinski
2024-04-26 18:33 ` [PATCH net-next v2 2/3] net/mlx4: link NAPI instances to queues and IRQs Joe Damato
2024-04-26 20:01 ` Jakub Kicinski
2024-04-26 18:33 ` [PATCH net-next v2 3/3] net/mlx4: support per-queue statistics via netlink Joe Damato
2024-04-26 20:01 ` Jakub Kicinski
2024-04-27 0:05 ` Joe Damato
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