From: Jakub Kicinski <kuba@kernel.org>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com,
pabeni@redhat.com, alexander.duyck@gmail.com,
hkallweit1@gmail.com, andrew@lunn.ch, willemb@google.com,
michael.chan@broadcom.com, jesse.brandeburg@intel.com,
anthony.l.nguyen@intel.com
Subject: Re: [PATCH net-next v3 7/7] net: piggy back on the memory barrier in bql when waking queues
Date: Thu, 6 Apr 2023 17:41:40 -0700 [thread overview]
Message-ID: <20230406174140.36930b15@kernel.org> (raw)
In-Reply-To: <ZC52VRfUOOObx2fw@gondor.apana.org.au>
On Thu, 6 Apr 2023 15:35:49 +0800 Herbert Xu wrote:
> Minor nit, I would write this as
>
> if (IS_ENABLED(CONFIG_BQL))
> netdev_tx_completed_queue(dev_queue, pkts, bytes);
> else if (bytes)
> smp_mb();
Will do!
> Actually, why is this checking bytes while the caller is checking
> pkts? Do we need to check them at all? If pkts/bytes is commonly
> non-zero, then we should just do a barrier unconditionally and make
> the uncommon path pay the penalty.
I wanted to keep the same semantics as netdev_tx_completed_queue()
which only barriers if (bytes). Not in the least to make it obvious
to someone looking at the code of netdev_txq_completed_mb() (and not
the comment above it) that it doesn't _always_ put a barrier in.
next prev parent reply other threads:[~2023-04-07 0:41 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-05 22:31 [PATCH net-next v3 0/7] net: lockless stop/wake combo macros Jakub Kicinski
2023-04-05 22:31 ` [PATCH net-next v3 1/7] docs: net: reformat driver.rst from a list to sections Jakub Kicinski
2023-04-05 22:31 ` [PATCH net-next v3 2/7] docs: net: move the probe and open/close sections of driver.rst up Jakub Kicinski
2023-04-05 22:31 ` [PATCH net-next v3 3/7] docs: net: use C syntax highlight in driver.rst Jakub Kicinski
2023-04-05 22:31 ` [PATCH net-next v3 4/7] net: provide macros for commonly copied lockless queue stop/wake code Jakub Kicinski
2023-04-06 7:22 ` Herbert Xu
2023-04-05 22:31 ` [PATCH net-next v3 5/7] ixgbe: use new queue try_stop/try_wake macros Jakub Kicinski
2023-04-05 22:31 ` [PATCH net-next v3 6/7] bnxt: " Jakub Kicinski
2023-04-05 22:31 ` [PATCH net-next v3 7/7] net: piggy back on the memory barrier in bql when waking queues Jakub Kicinski
2023-04-06 7:35 ` Herbert Xu
2023-04-07 0:41 ` Jakub Kicinski [this message]
2023-04-12 6:06 ` Herbert Xu
2023-04-12 13:54 ` Jakub Kicinski
2023-04-13 2:31 ` Herbert Xu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230406174140.36930b15@kernel.org \
--to=kuba@kernel.org \
--cc=alexander.duyck@gmail.com \
--cc=andrew@lunn.ch \
--cc=anthony.l.nguyen@intel.com \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=herbert@gondor.apana.org.au \
--cc=hkallweit1@gmail.com \
--cc=jesse.brandeburg@intel.com \
--cc=michael.chan@broadcom.com \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=willemb@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.