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[149.6.153.186]) by smtp.gmail.com with ESMTPSA id a3sm2211571wmb.35.2019.06.14.03.22.50 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Fri, 14 Jun 2019 03:22:50 -0700 (PDT) Date: Fri, 14 Jun 2019 12:22:48 +0200 From: Lorenzo Bianconi To: Stanislaw Gruszka Cc: Lorenzo Bianconi , kvalo@codeaurora.org, linux-wireless@vger.kernel.org, nbd@nbd.name Subject: Re: [PATCH v3 wireless-drivers 3/3] mt76: usb: do not always copy the first part of received frames Message-ID: <20190614102247.GB2669@localhost.localdomain> References: <1a9566c0a41ad0d940487a9d3f0008993c075ef2.1560461404.git.lorenzo@kernel.org> <20190614075303.GB3395@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="O5XBE6gyVG5Rl6Rj" Content-Disposition: inline In-Reply-To: <20190614075303.GB3395@redhat.com> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org --O5XBE6gyVG5Rl6Rj Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > On Thu, Jun 13, 2019 at 11:43:13PM +0200, Lorenzo Bianconi wrote: > > Set usb buffer size taking into account skb_shared_info in order to > > not always copy the first part of received frames if A-MSDU is enabled > > for SG capable devices. Moreover align usb buffer size to max_ep > > boundaries and set buf_size to PAGE_SIZE even for sg case >=20 > I think this should not be applied to wirless-drivers, only first patch > that fix the bug and optimizations should be done in -next. ack, right. I think patch 2/3 and 3/3 can go directly in Felix's tree >=20 > > + int i, data_size; > > =20 > > + data_size =3D rounddown(SKB_WITH_OVERHEAD(q->buf_size), > > + dev->usb.in_ep[MT_EP_IN_PKT_RX].max_packet); > > for (i =3D 0; i < nsgs; i++) { > > struct page *page; > > void *data; > > @@ -302,7 +304,7 @@ mt76u_fill_rx_sg(struct mt76_dev *dev, struct mt76_= queue *q, struct urb *urb, > > =20 > > page =3D virt_to_head_page(data); > > offset =3D data - page_address(page); > > - sg_set_page(&urb->sg[i], page, q->buf_size, offset); > > + sg_set_page(&urb->sg[i], page, data_size, offset); > > > - q->buf_size =3D dev->usb.sg_en ? MT_RX_BUF_SIZE : PAGE_SIZE; > > q->ndesc =3D MT_NUM_RX_ENTRIES; > > + q->buf_size =3D PAGE_SIZE; > > + >=20 > This should be associated with decrease of MT_SG_MAX_SIZE to value that > is actually needed and currently this is 2 for 4k AMSDU. MT_SG_MAX_SIZE is used even on tx side and I do not think we will end up wi= th a huge difference here >=20 > However I don't think allocating 2 pages to avoid ieee80211 header and SN= AP > copy is worth to do. For me best approach would be allocate 1 page for > 4k AMSDU, 2 for 8k and 3 for 12k (still using sg, but without data_size > change to avoid 32B copying). =46rom my point of view it is better to avoid copying if it is possible. Ar= e you sure there is no difference? Regards, Lorenzo >=20 > Stanislaw --O5XBE6gyVG5Rl6Rj Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTquNwa3Txd3rGGn7Y6cBh0uS2trAUCXQN1dAAKCRA6cBh0uS2t rI7pAP0ebDhzTgKi0vXfNqezYTetbQ2W3unzKo1krbgT/Et01QD/Y3azDk75Y/Hd PdzSONdGoeQQI8GGk+rBEMS90gz2OQ0= =YcOb -----END PGP SIGNATURE----- --O5XBE6gyVG5Rl6Rj--