From: Jakub Kicinski <kuba@kernel.org>
To: Jason Xing <kerneljasonxing@gmail.com>
Cc: davem@davemloft.net, edumazet@google.com, pabeni@redhat.com,
bjorn@kernel.org, magnus.karlsson@intel.com,
maciej.fijalkowski@intel.com, jonathan.lemon@gmail.com,
sdf@fomichev.me, ast@kernel.org, daniel@iogearbox.net,
hawk@kernel.org, john.fastabend@gmail.com, horms@kernel.org,
andrew+netdev@lunn.ch, bpf@vger.kernel.org,
netdev@vger.kernel.org, Jason Xing <kernelxing@tencent.com>
Subject: Re: [PATCH net-next 1/2] xsk: avoid using heavy lock when the pool is not shared
Date: Tue, 28 Oct 2025 17:29:03 -0700 [thread overview]
Message-ID: <20251028172903.677f46ba@kernel.org> (raw)
In-Reply-To: <20251025065310.5676-2-kerneljasonxing@gmail.com>
On Sat, 25 Oct 2025 14:53:09 +0800 Jason Xing wrote:
> static int xsk_cq_reserve_locked(struct xsk_buff_pool *pool)
> {
> + bool lock = !list_is_singular(&pool->xsk_tx_list);
> unsigned long flags;
> int ret;
>
> - spin_lock_irqsave(&pool->cq_lock, flags);
> + if (lock)
> + spin_lock_irqsave(&pool->cq_lock, flags);
> ret = xskq_prod_reserve(pool->cq);
> - spin_unlock_irqrestore(&pool->cq_lock, flags);
> + if (lock)
> + spin_unlock_irqrestore(&pool->cq_lock, flags);
Please explain in the commit message what guarantees that the list will
remain singular until the function exits.
--
pw-bot: cr
next prev parent reply other threads:[~2025-10-29 0:29 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-25 6:53 [PATCH net-next 0/2] xsk: mitigate the side effect of cq_lock Jason Xing
2025-10-25 6:53 ` [PATCH net-next 1/2] xsk: avoid using heavy lock when the pool is not shared Jason Xing
2025-10-29 0:29 ` Jakub Kicinski [this message]
2025-10-29 1:36 ` Jason Xing
2025-10-29 15:48 ` Maciej Fijalkowski
2025-10-29 23:43 ` Jason Xing
2025-10-25 6:53 ` [PATCH net-next 2/2] xsk: use a smaller new lock for shared pool case Jason Xing
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