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 F090EDF4C for ; Mon, 15 Jan 2024 09:52:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bgPQwTTe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7CA35C433C7; Mon, 15 Jan 2024 09:52:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1705312321; bh=tq1LvtkAdS6HI+mHnlrvFlhiN8d0NA5zwM1YvZL8ZFk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bgPQwTTe4RTIKeCVwYiJ3gZtH8k9IwZRLxoNXGyudIrDIPo/LLsrsqso1hKgHCCPq 3ycEzmBPIvjcFlId4OAnU/8rcFHZ8S5la9ja47trpHFwGG/xEECGvolMGVTokBMSf5 gauD6KYIiLtyPZhyLHM5P5l7Hi4VbI7/S7KgBk0DlqoUta773ywklm58ApKD0fuuYa lj40KwuWtvA/NU3fSrmGMT2M3bXGuvhIRwJ0bQ7Il9eji6KbPt5vffEy0gRvnDU5mj 3jEjwqHl4/JuraOkUNVKyGJujHdmySkyx62VhL+oxI1huP7sIGyu/NRCbwpHCIndrY SEWKxai0V+XHA== Date: Mon, 15 Jan 2024 17:39:10 +0800 From: Jisheng Zhang To: Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] riscv: mm: still create swiotlb buffer for kmalloc() bouncing if required Message-ID: References: <20231202134224.4029-1-jszhang@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20231202134224.4029-1-jszhang@kernel.org> On Sat, Dec 02, 2023 at 09:42:24PM +0800, Jisheng Zhang wrote: > After commit f51f7a0fc2f4 ("riscv: enable DMA_BOUNCE_UNALIGNED_KMALLOC > for !dma_coherent"), for non-coherent platforms with less than 4GB > memory, we rely on users to pass "swiotlb=mmnn,force" kernel parameters > to enable DMA bouncing for unaligned kmalloc() buffers. Now let's go > further: If no bouncing needed for ZONE_DMA, let kernel automatically > allocate 1MB swiotlb buffer per 1GB of RAM for kmalloc() bouncing on > non-coherent platforms, so that no need to pass "swiotlb=mmnn,force" > any more. > > The math of "1MB swiotlb buffer per 1GB of RAM for kmalloc() bouncing" > is taken from arm64. Users can still force smaller swiotlb buffer by > passing "swiotlb=mmnn". and this one is missed either. let me know if there's something need to be done for merging. Thanks in advance, > > Signed-off-by: Jisheng Zhang > --- > > since v2: > - fix build error if CONFIG_RISCV_DMA_NONCOHERENT=n > > arch/riscv/include/asm/cache.h | 2 +- > arch/riscv/mm/init.c | 16 +++++++++++++++- > 2 files changed, 16 insertions(+), 2 deletions(-) > > diff --git a/arch/riscv/include/asm/cache.h b/arch/riscv/include/asm/cache.h > index 2174fe7bac9a..570e9d8acad1 100644 > --- a/arch/riscv/include/asm/cache.h > +++ b/arch/riscv/include/asm/cache.h > @@ -26,8 +26,8 @@ > > #ifndef __ASSEMBLY__ > > -#ifdef CONFIG_RISCV_DMA_NONCOHERENT > extern int dma_cache_alignment; > +#ifdef CONFIG_RISCV_DMA_NONCOHERENT > #define dma_get_cache_alignment dma_get_cache_alignment > static inline int dma_get_cache_alignment(void) > { > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c > index 2e011cbddf3a..cbcb9918f721 100644 > --- a/arch/riscv/mm/init.c > +++ b/arch/riscv/mm/init.c > @@ -162,11 +162,25 @@ static void print_vm_layout(void) { } > > void __init mem_init(void) > { > + bool swiotlb = max_pfn > PFN_DOWN(dma32_phys_limit); > #ifdef CONFIG_FLATMEM > BUG_ON(!mem_map); > #endif /* CONFIG_FLATMEM */ > > - swiotlb_init(max_pfn > PFN_DOWN(dma32_phys_limit), SWIOTLB_VERBOSE); > + if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && !swiotlb && > + dma_cache_alignment != 1) { > + /* > + * If no bouncing needed for ZONE_DMA, allocate 1MB swiotlb > + * buffer per 1GB of RAM for kmalloc() bouncing on > + * non-coherent platforms. > + */ > + unsigned long size = > + DIV_ROUND_UP(memblock_phys_mem_size(), 1024); > + swiotlb_adjust_size(min(swiotlb_size_or_default(), size)); > + swiotlb = true; > + } > + > + swiotlb_init(swiotlb, SWIOTLB_VERBOSE); > memblock_free_all(); > > print_vm_layout(); > -- > 2.42.0 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv