From: Simon Horman <horms@kernel•org>
To: Jakub Kicinski <kuba@kernel•org>
Cc: davem@davemloft•net, netdev@vger•kernel.org, edumazet@google•com,
pabeni@redhat•com,
Alexander Lobakin <aleksander.lobakin@intel•com>,
alexs@kernel•org, siyanteng@loongson•cn,
jesse.brandeburg@intel•com, anthony.l.nguyen@intel•com,
alexandre.torgue@foss•st.com, joabreu@synopsys•com,
mcoquelin.stm32@gmail•com, intel-wired-lan@lists•osuosl.org
Subject: Re: [PATCH net-next v2] net: remove gfp_mask from napi_alloc_skb()
Date: Thu, 28 Mar 2024 11:32:02 +0000 [thread overview]
Message-ID: <20240328113202.GH403975@kernel.org> (raw)
In-Reply-To: <20240327040213.3153864-1-kuba@kernel.org>
On Tue, Mar 26, 2024 at 09:02:12PM -0700, Jakub Kicinski wrote:
> __napi_alloc_skb() is napi_alloc_skb() with the added flexibility
> of choosing gfp_mask. This is a NAPI function, so GFP_ATOMIC is
> implied. The only practical choice the caller has is whether to
> set __GFP_NOWARN. But that's a false choice, too, allocation failures
> in atomic context will happen, and printing warnings in logs,
> effectively for a packet drop, is both too much and very likely
> non-actionable.
>
> This leads me to a conclusion that most uses of napi_alloc_skb()
> are simply misguided, and should use __GFP_NOWARN in the first
> place. We also have a "standard" way of reporting allocation
> failures via the queue stat API (qstats::rx-alloc-fail).
>
> The direct motivation for this patch is that one of the drivers
> used at Meta calls napi_alloc_skb() (so prior to this patch without
> __GFP_NOWARN), and the resulting OOM warning is the top networking
> warning in our fleet.
>
> Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel•com>
> Signed-off-by: Jakub Kicinski <kuba@kernel•org>
Reviewed-by: Simon Horman <horms@kernel•org>
next prev parent reply other threads:[~2024-03-28 11:32 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-27 4:02 [PATCH net-next v2] net: remove gfp_mask from napi_alloc_skb() Jakub Kicinski
2024-03-28 11:32 ` Simon Horman [this message]
2024-03-28 11:48 ` Eric Dumazet
2024-03-29 1:50 ` patchwork-bot+netdevbpf
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