From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D4BB17E; Tue, 1 Aug 2023 00:31:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0EFA5C433C7; Tue, 1 Aug 2023 00:31:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690849881; bh=edKPUxJSfxSwSgMp4ELrc17mhd6XvhBB05dcUDTu8PM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=o52owDH10zGOWCtUIT8xi646am/uSlnvhQg5alGDBcj6z+WgLHgQr14m1GIENgyko YCmsi6UwSKPXC7H5UCme6ceAfT6mg2qCZwNrxhfhvPhV5FhEMAtNa0LMrkOigaeRNi XTR6LkX+85ifqjNVdK3q2b4/wE0EPneTiOmHgfqx/R9wt+n1Y+4Apn9dxBkwnhDDv+ qedsv/MKItKNBFjYfsI/41KDd7LuNjZNg2g+8G3Rq5DEsWapBovfCf1dr33K9NKSmd vIYfqGXElKeaxFaZo2wKq4pgFgsue0aFEu1FydnI+z4eYoBGQv+g71nN+3Qv2BVXHE 0ju5++uayZdLg== Date: Mon, 31 Jul 2023 17:31:19 -0700 From: Jakub Kicinski To: Haiyang Zhang Cc: linux-hyperv@vger.kernel.org, netdev@vger.kernel.org, decui@microsoft.com, kys@microsoft.com, paulros@microsoft.com, olaf@aepfle.de, vkuznets@redhat.com, davem@davemloft.net, wei.liu@kernel.org, edumazet@google.com, pabeni@redhat.com, leon@kernel.org, longli@microsoft.com, ssengar@linux.microsoft.com, linux-rdma@vger.kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, bpf@vger.kernel.org, ast@kernel.org, sharmaajay@microsoft.com, hawk@kernel.org, tglx@linutronix.de, shradhagupta@linux.microsoft.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH V4,net-next] net: mana: Add page pool for RX buffers Message-ID: <20230731173119.3ca14894@kernel.org> In-Reply-To: <1690580767-18937-1-git-send-email-haiyangz@microsoft.com> References: <1690580767-18937-1-git-send-email-haiyangz@microsoft.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 28 Jul 2023 14:46:07 -0700 Haiyang Zhang wrote: > static void *mana_get_rxfrag(struct mana_rxq *rxq, struct device *dev, > - dma_addr_t *da, bool is_napi) > + dma_addr_t *da, bool *from_pool, bool is_napi) > { > struct page *page; > void *va; > > + *from_pool = false; > + > /* Reuse XDP dropped page if available */ > if (rxq->xdp_save_va) { > va = rxq->xdp_save_va; > @@ -1533,17 +1543,22 @@ static void *mana_get_rxfrag(struct mana_rxq *rxq, struct device *dev, > return NULL; > } > } else { > - page = dev_alloc_page(); > + page = page_pool_dev_alloc_pages(rxq->page_pool); > if (!page) > return NULL; > > + *from_pool = true; > va = page_to_virt(page); > } > > *da = dma_map_single(dev, va + rxq->headroom, rxq->datasize, > DMA_FROM_DEVICE); > if (dma_mapping_error(dev, *da)) { > - put_page(virt_to_head_page(va)); > + if (*from_pool) > + page_pool_put_full_page(rxq->page_pool, page, is_napi); AFAICT you only pass the is_napi to recycle in case of error? It's fine to always pass in false, passing true enables some optimizations but it's not worth trying to optimize error paths. Otherwise you may be passing in true, even tho budget was 0, see the recently added warnings in this doc: https://www.kernel.org/doc/html/next/networking/napi.html In general the driver seems to be processing Rx regardless of budget? This looks like a bug which should be fixed with a separate patch for the net tree.. -- pw-bot: cr