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[188.216.41.250]) by smtp.gmail.com with ESMTPSA id t16sm1875652edi.60.2021.03.11.11.44.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 11 Mar 2021 11:44:06 -0800 (PST) From: Matteo Croce To: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jonathan Lemon , "David S. Miller" , Ilias Apalodimas , Jesper Dangaard Brouer , Lorenzo Bianconi , Saeed Mahameed Subject: [RFC net-next 1/6] xdp: reduce size of struct xdp_mem_info Date: Thu, 11 Mar 2021 20:42:51 +0100 Message-Id: <20210311194256.53706-2-mcroce@linux.microsoft.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210311194256.53706-1-mcroce@linux.microsoft.com> References: <20210311194256.53706-1-mcroce@linux.microsoft.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC From: Jesper Dangaard Brouer It is possible to compress/reduce the size of struct xdp_mem_info. This change reduce struct xdp_mem_info from 8 bytes to 4 bytes. The member xdp_mem_info.id can be reduced to u16, as the mem_id_ht rhashtable in net/core/xdp.c is already limited by MEM_ID_MAX=0xFFFE which can safely fit in u16. The member xdp_mem_info.type could be reduced more than u16, as it stores the enum xdp_mem_type, but due to alignment it is only reduced to u16. Signed-off-by: Jesper Dangaard Brouer --- include/net/xdp.h | 4 ++-- net/core/xdp.c | 8 ++++---- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/include/net/xdp.h b/include/net/xdp.h index a5bc214a49d9..c35864d59113 100644 --- a/include/net/xdp.h +++ b/include/net/xdp.h @@ -48,8 +48,8 @@ enum xdp_mem_type { #define XDP_XMIT_FLAGS_MASK XDP_XMIT_FLUSH struct xdp_mem_info { - u32 type; /* enum xdp_mem_type, but known size type */ - u32 id; + u16 type; /* enum xdp_mem_type, but known size type */ + u16 id; }; struct page_pool; diff --git a/net/core/xdp.c b/net/core/xdp.c index 05354976c1fc..3dd47ed83778 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -35,11 +35,11 @@ static struct rhashtable *mem_id_ht; static u32 xdp_mem_id_hashfn(const void *data, u32 len, u32 seed) { - const u32 *k = data; - const u32 key = *k; + const u16 *k = data; + const u16 key = *k; BUILD_BUG_ON(sizeof_field(struct xdp_mem_allocator, mem.id) - != sizeof(u32)); + != sizeof(u16)); /* Use cyclic increasing ID as direct hash key */ return key; @@ -49,7 +49,7 @@ static int xdp_mem_id_cmp(struct rhashtable_compare_arg *arg, const void *ptr) { const struct xdp_mem_allocator *xa = ptr; - u32 mem_id = *(u32 *)arg->key; + u16 mem_id = *(u16 *)arg->key; return xa->mem.id != mem_id; }