Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758443AbaGDNfh (ORCPT ); Fri, 4 Jul 2014 09:35:37 -0400 Received: from mail-wg0-f43.google.com ([74.125.82.43]:63906 "EHLO mail-wg0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753796AbaGDNfg (ORCPT ); Fri, 4 Jul 2014 09:35:36 -0400 Date: Fri, 4 Jul 2014 15:35:22 +0200 From: Thierry Reding To: Laura Abbott Cc: Will Deacon , Catalin Marinas , David Riley , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ritesh Harjain , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCHv4 5/5] arm64: Add atomic pool for non-coherent and CMA allocations. Message-ID: <20140704133517.GA9860@ulmo> References: <1404324218-4743-1-git-send-email-lauraa@codeaurora.org> <1404324218-4743-6-git-send-email-lauraa@codeaurora.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="WIyZ46R2i8wDzkSu" Content-Disposition: inline In-Reply-To: <1404324218-4743-6-git-send-email-lauraa@codeaurora.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --WIyZ46R2i8wDzkSu Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jul 02, 2014 at 11:03:38AM -0700, Laura Abbott wrote: [...] > diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c [...] > +static struct gen_pool *atomic_pool; > + > +#define DEFAULT_DMA_COHERENT_POOL_SIZE SZ_256K > +static size_t atomic_pool_size =3D DEFAULT_DMA_COHERENT_POOL_SIZE; There doesn't seem to be much use for this since it can't be overridden via init_dma_coherent_pool_size like on ARM. > +static int __free_from_pool(void *start, size_t size) > +{ > + if (!__in_atomic_pool(start, size)) > + return 0; > + > + gen_pool_free(atomic_pool, (unsigned long)start, size); > + > + return 1; > +} > + > + There's a gratuituous blank line here. > static void *__dma_alloc_coherent(struct device *dev, size_t size, > dma_addr_t *dma_handle, gfp_t flags, > struct dma_attrs *attrs) > @@ -53,7 +103,8 @@ static void *__dma_alloc_coherent(struct device *dev, = size_t size, > if (IS_ENABLED(CONFIG_ZONE_DMA) && > dev->coherent_dma_mask <=3D DMA_BIT_MASK(32)) > flags |=3D GFP_DMA; > - if (IS_ENABLED(CONFIG_DMA_CMA)) { > + > + if (!(flags & __GFP_WAIT) && IS_ENABLED(CONFIG_DMA_CMA)) { I think the diff would be more readable here if this wasn't introducing a blank linke and kept the IS_ENABLED() first. > struct page *page; > =20 > size =3D PAGE_ALIGN(size); > @@ -73,50 +124,56 @@ static void __dma_free_coherent(struct device *dev, = size_t size, > void *vaddr, dma_addr_t dma_handle, > struct dma_attrs *attrs) > { > + bool freed; > + phys_addr_t paddr =3D dma_to_phys(dev, dma_handle); > + > if (dev =3D=3D NULL) { > WARN_ONCE(1, "Use an actual device structure for DMA allocation\n"); > return; > } > =20 > - if (IS_ENABLED(CONFIG_DMA_CMA)) { > - phys_addr_t paddr =3D dma_to_phys(dev, dma_handle); > =20 > - dma_release_from_contiguous(dev, The above leaves an unnecessary blank line in place. > ptr =3D __dma_alloc_coherent(dev, size, dma_handle, flags, attrs); > if (!ptr) > goto no_mem; > - map =3D kmalloc(sizeof(struct page *) << order, flags & ~GFP_DMA); > - if (!map) > - goto no_map; > =20 > /* remove any dirty cache lines on the kernel alias */ > __dma_flush_range(ptr, ptr + size); > =20 > + Adds an unnecessary blank line. > @@ -332,6 +391,67 @@ static struct notifier_block amba_bus_nb =3D { > =20 > extern int swiotlb_late_init_with_default_size(size_t default_size); > =20 > +static int __init atomic_pool_init(void) > +{ > + pgprot_t prot =3D __pgprot(PROT_NORMAL_NC); > + unsigned long nr_pages =3D atomic_pool_size >> PAGE_SHIFT; > + struct page *page; > + void *addr; > + > + There's another gratuituous blank line here... > + if (dev_get_cma_area(NULL)) > + page =3D dma_alloc_from_contiguous(NULL, nr_pages, > + get_order(atomic_pool_size)); > + else > + page =3D alloc_pages(GFP_KERNEL, get_order(atomic_pool_size)); > + > + and here. > + if (page) { > + int ret; > + > + atomic_pool =3D gen_pool_create(PAGE_SHIFT, -1); > + if (!atomic_pool) > + goto free_page; > + > + addr =3D dma_common_contiguous_remap(page, atomic_pool_size, > + VM_USERMAP, prot, atomic_pool_init); > + > + if (!addr) > + goto destroy_genpool; > + > + memset(addr, 0, atomic_pool_size); > + __dma_flush_range(addr, addr + atomic_pool_size); > + > + ret =3D gen_pool_add_virt(atomic_pool, (unsigned long)addr, > + page_to_phys(page), > + atomic_pool_size, -1); > + if (ret) > + goto remove_mapping; > + > + gen_pool_set_algo(atomic_pool, > + gen_pool_first_fit_order_align, NULL); > + > + pr_info("DMA: preallocated %zd KiB pool for atomic allocations\n", I think this should be "%zu" because atomic_pool_size is a size_t, not a ssize_t. > + atomic_pool_size / 1024); > + return 0; > + } > + goto out; > + > +remove_mapping: > + dma_common_free_remap(addr, atomic_pool_size, VM_USERMAP); > +destroy_genpool: > + gen_pool_destroy(atomic_pool); > + atomic_pool =3D=3D NULL; This probably doesn't belong here. > +free_page: > + if (!dma_release_from_contiguous(NULL, page, nr_pages)) > + __free_pages(page, get_order(atomic_pool_size)); You use get_order(atomic_pool_size) a lot, perhaps it should be a temporary variable? > +out: > + pr_err("DMA: failed to allocate %zx KiB pool for atomic coherent alloca= tion\n", > + atomic_pool_size / 1024); Print in decimal rather than hexadecimal? 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