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[204.195.112.43]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-896c3107398sm3273361b3a.17.2026.10.11.12.50.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 11 Oct 2026 12:50:18 -0700 (PDT) Date: Sun, 11 Oct 2026 12:50:16 -0700 From: Stephen Hemminger To: Marat Khalili Cc: Konstantin Ananyev , dev@dpdk.org Subject: Re: [PATCH 5/9] bpf: remove redundant memory barrier on unload Message-ID: <20261011125016.15772f7c@phoenix.local> In-Reply-To: <20261011182158.124246-6-qm2k21@gmail.com> References: <20261011182158.124246-1-qm2k21@gmail.com> <20261011182158.124246-6-qm2k21@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On Sun, 11 Oct 2026 18:21:53 +0000 Marat Khalili wrote: > In bpf_eth_cbi_unload(), rte_smp_mb() was called immediately before > bpf_eth_cbi_wait(), which itself starts with rte_smp_mb(). > > Remove the redundant rte_smp_mb() call from bpf_eth_cbi_unload() and > update the unload sequence diagram accordingly. > > Signed-off-by: Marat Khalili > --- > lib/bpf/bpf_pkt.c | 3 --- > 1 file changed, 3 deletions(-) > > diff --git a/lib/bpf/bpf_pkt.c b/lib/bpf/bpf_pkt.c > index 7ee16cfa69..68671848e9 100644 > --- a/lib/bpf/bpf_pkt.c > +++ b/lib/bpf/bpf_pkt.c > @@ -62,8 +62,6 @@ > * | | | | | | > * rte_smp_mb() | | | | | > * | | | | | | > - * rte_smp_mb() | | | | | > - * | | | | | | > * +-if use is odd | | | | if cb not NULL-+ > * | | | | | | | | > * | +------------ fetch odd ------------>| | |<-- execute --+ | > @@ -502,7 +500,6 @@ bpf_eth_cbi_unload(struct bpf_eth_cbi *bc) > { > /* mark this cbi as empty */ > bc->cb = NULL; > - rte_smp_mb(); > > /* make sure datapath doesn't use bpf anymore, then destroy bpf */ > bpf_eth_cbi_wait(bc); I think this already covered by: https://patchwork.dpdk.org/project/dpdk/patch/20261008233649.1260843-2-stephen@networkplumber.org/