Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753137Ab0LQEQn (ORCPT ); Thu, 16 Dec 2010 23:16:43 -0500 Received: from ganesha.gnumonks.org ([213.95.27.120]:37581 "EHLO ganesha.gnumonks.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751803Ab0LQEQi (ORCPT ); Thu, 16 Dec 2010 23:16:38 -0500 From: KyongHo Cho To: KyongHo Cho Cc: Kyungmin Park , Kukjin Kim , Inho Lee , Inki Dae , Andrew Morton , Ankita Garg , Daniel Walker , Johan MOSSBERG , KAMEZAWA Hiroyuki , Marek Szyprowski , Mel Gorman , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-samsung-soc@vger.kernel.org, Michal Nazarewicz Subject: [RFCv2,3/8] mm: vcm: physical memory allocator added Date: Fri, 17 Dec 2010 12:56:22 +0900 Message-Id: <1292558187-17348-4-git-send-email-pullip.cho@samsung.com> X-Mailer: git-send-email 1.6.2.5 In-Reply-To: <1292558187-17348-3-git-send-email-pullip.cho@samsung.com> References: <1292558187-17348-1-git-send-email-pullip.cho@samsung.com> <1292558187-17348-2-git-send-email-pullip.cho@samsung.com> <1292558187-17348-3-git-send-email-pullip.cho@samsung.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 13551 Lines: 440 From: Michal Nazarewicz This commits adds vcm_phys_alloc() function with some accompanying functions which allocates physical memory. This should be used from withing alloc or phys callback of a VCM driver if one does not want to provide its own allocator. Signed-off-by: Michal Nazarewicz Signed-off-by: Kyungmin Park --- Documentation/virtual-contiguous-memory.txt | 31 ++++ include/linux/vcm-drv.h | 88 ++++++++++ mm/Kconfig | 9 + mm/vcm.c | 249 +++++++++++++++++++++++++++ 4 files changed, 377 insertions(+), 0 deletions(-) diff --git a/Documentation/virtual-contiguous-memory.txt b/Documentation/virtual-contiguous-memory.txt index 2008465..10a0638 100644 --- a/Documentation/virtual-contiguous-memory.txt +++ b/Documentation/virtual-contiguous-memory.txt @@ -672,6 +672,37 @@ Both phys and alloc callbacks need to provide a free callbakc along with the vc_phys structure, which will, as one may imagine, free allocated space when user calls vcm_free(). +Unless VCM driver needs some special handling of physical memory, the +vcm_phys_alloc() function can be used: + + struct vcm_phys *__must_check + vcm_phys_alloc(resource_size_t size, unsigned flags, + const unsigned char *orders); + +The last argument of this function (orders) is an array of orders of +page sizes that function should try to allocate. This array must be +sorted from highest order to lowest and the last entry must be zero. + +For instance, an array { 8, 4, 0 } means that the function should try +and allocate 1MiB, 64KiB and 4KiB pages (this is assuming PAGE_SIZE is +4KiB which is true for all supported architectures). For example, if +requested size is 2MiB and 68 KiB, the function will try to allocate +two 1MiB pages, one 64KiB page and one 4KiB page. This may be useful +when the mapping is written to the MMU since the largest possible +pages will be used reducing the number of entries. + +The function allocates memory from DMA32 zone. If driver has some +other requirements (that is require different GFP flags) it can use +__vcm_phys_alloc() function which, besides arguments that +vcm_phys_alloc() accepts, take GFP flags as the last argument: + + struct vcm_phys *__must_check + __vcm_phys_alloc(resource_size_t size, unsigned flags, + const unsigned char *orders, gfp_t gfp); + +However, if those functions are used, VCM driver needs to select an +VCM_PHYS Kconfig option or oterwise they won't be available. + All those operations may assume that size is a non-zero and divisible by PAGE_SIZE. diff --git a/include/linux/vcm-drv.h b/include/linux/vcm-drv.h index d7ae660..536b051 100644 --- a/include/linux/vcm-drv.h +++ b/include/linux/vcm-drv.h @@ -114,4 +114,92 @@ struct vcm_phys { */ struct vcm *__must_check vcm_init(struct vcm *vcm); +#ifdef CONFIG_VCM_PHYS + +/** + * __vcm_phys_alloc() - allocates physical discontiguous space + * @size: size of the block to allocate. + * @flags: additional allocation flags; XXX FIXME: document + * @orders: array of orders of pages supported by the MMU sorted from + * the largest to the smallest. The last element is always + * zero (which means 4K page). + * @gfp: the gfp flags for pages to allocate. + * + * This function tries to allocate a physical discontiguous space in + * such a way that it allocates the largest possible blocks from the + * sizes donated by the @orders array. So if @orders is { 8, 0 } + * (which means 1MiB and 4KiB pages are to be used) and requested + * @size is 2MiB and 12KiB the function will try to allocate two 1MiB + * pages and three 4KiB pages (in that order). If big page cannot be + * allocated the function will still try to allocate more smaller + * pages. + */ +struct vcm_phys *__must_check +__vcm_phys_alloc(resource_size_t size, unsigned flags, + const unsigned char *orders, gfp_t gfp); + +/** + * vcm_phys_alloc() - allocates physical discontiguous space + * @size: size of the block to allocate. + * @flags: additional allocation flags; XXX FIXME: document + * @orders: array of orders of pages supported by the MMU sorted from + * the largest to the smallest. The last element is always + * zero (which means 4K page). + * + * This function tries to allocate a physical discontiguous space in + * such a way that it allocates the largest possible blocks from the + * sizes donated by the @orders array. So if @orders is { 8, 0 } + * (which means 1MiB and 4KiB pages are to be used) and requested + * @size is 2MiB and 12KiB the function will try to allocate two 1MiB + * pages and three 4KiB pages (in that order). If big page cannot be + * allocated the function will still try to allocate more smaller + * pages. + */ +static inline struct vcm_phys *__must_check +vcm_phys_alloc(resource_size_t size, unsigned flags, + const unsigned char *orders) { + return __vcm_phys_alloc(size, flags, orders, GFP_DMA32); +} + +/** + * vcm_phys_walk() - helper function for mapping physical pages + * @vaddr: virtual address to map/unmap physical space to/from + * @phys: physical space + * @orders: array of orders of pages supported by the MMU sorted from + * the largest to the smallest. The last element is always + * zero (which means 4K page). + * @callback: function called for each page. + * @recover: function called for each page when @callback returns + * negative number; if it also returns negative number + * function terminates; may be NULL. + * @priv: private data for the callbacks. + * + * This function walks through @phys trying to mach largest possible + * page size donated by @orders. For each such page @callback is + * called. If @callback returns negative number the function calls + * @recover for each page @callback was called successfully. + * + * So, for instance, if we have a physical memory which consist of + * 1Mib part and 8KiB part and @orders is { 8, 0 } (which means 1MiB + * and 4KiB pages are to be used), @callback will be called first with + * 1MiB page and then two times with 4KiB page. This is of course + * provided that @vaddr has correct alignment. + * + * The idea is for hardware MMU drivers to call this function and + * provide a callbacks for mapping/unmapping a single page. The + * function divides the region into pages that the MMU can handle. + * + * If @callback at one point returns a negative number this is the + * return value of the function; otherwise zero is returned. + */ +int vcm_phys_walk(dma_addr_t vaddr, const struct vcm_phys *phys, + const unsigned char *orders, + int (*callback)(dma_addr_t vaddr, dma_addr_t paddr, + unsigned order, void *priv), + int (*recovery)(dma_addr_t vaddr, dma_addr_t paddr, + unsigned order, void *priv), + void *priv); + +#endif + #endif diff --git a/mm/Kconfig b/mm/Kconfig index b937f32..00d975e 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -360,6 +360,15 @@ config VCM_RES_REFCNT This enables reference counting on a reservation to make sharing and migrating the ownership of the reservation easier. +config VCM_PHYS + bool "VCM physical allocation wrappers" + depends on VCM && MODULES + help + This enables the vcm_phys family of functions provided for VCM + drivers. If a VCM driver is built that requires this option, it + will be automatically selected. You select it if you are going to + build external modules that will use this functionality. + # # UP and nommu archs use km based percpu allocator # diff --git a/mm/vcm.c b/mm/vcm.c index 5819f0f..6804114 100644 --- a/mm/vcm.c +++ b/mm/vcm.c @@ -319,3 +319,252 @@ struct vcm *__must_check vcm_init(struct vcm *vcm) return vcm; } EXPORT_SYMBOL_GPL(vcm_init); + + +/************************ Physical memory management ************************/ + +#ifdef CONFIG_VCM_PHYS + +struct vcm_phys_list { + struct vcm_phys_list *next; + unsigned count; + struct vcm_phys_part parts[31]; +}; + +static struct vcm_phys_list *__must_check +vcm_phys_alloc_list_order(struct vcm_phys_list *last, resource_size_t *pages, + unsigned flags, unsigned order, unsigned *total, + gfp_t gfp) +{ + unsigned count; + + count = *pages >> order; + + do { + struct page *page = alloc_pages(gfp, order); + + if (!page) + /* + * If allocation failed we may still + * try to continua allocating smaller + * pages. + */ + break; + + if (last->count == ARRAY_SIZE(last->parts)) { + struct vcm_phys_list *l; + l = kmalloc(sizeof *l, GFP_KERNEL); + if (!l) + return NULL; + + l->next = NULL; + l->count = 0; + last->next = l; + last = l; + } + + last->parts[last->count].start = page_to_phys(page); + last->parts[last->count].size = (1 << order); + last->parts[last->count].page = page; + ++last->count; + ++*total; + *pages -= 1 << order; + } while (--count); + + return last; +} + +static unsigned __must_check +vcm_phys_alloc_list(struct vcm_phys_list *first, + resource_size_t size, unsigned flags, + const unsigned char *orders, gfp_t gfp) +{ + struct vcm_phys_list *last = first; + unsigned total_parts = 0; + resource_size_t pages; + + /* + * We are trying to allocate as large pages as possible but + * not larger then pages that MMU driver that called us + * supports (ie. the ones provided by page_sizes). This makes + * it possible to map the region using fewest possible number + * of entries. + */ + pages = size >> PAGE_SHIFT; + do { + while (!(pages >> *orders)) + ++orders; + + last = vcm_phys_alloc_list_order(last, &pages, flags, *orders, + &total_parts, gfp); + if (!last) + return 0; + + } while (*orders++ && pages); + + if (pages) + return 0; + + return total_parts; +} + +static void vcm_phys_free_parts(struct vcm_phys_part *parts, unsigned count) +{ + do { + __free_pages(parts->page, ffs(parts->size) - 1 - PAGE_SHIFT); + } while (++parts, --count); +} + +static void vcm_phys_free(struct vcm_phys *phys) +{ + vcm_phys_free_parts(phys->parts, phys->count); + kfree(phys); +} + +struct vcm_phys *__must_check +__vcm_phys_alloc(resource_size_t size, unsigned flags, + const unsigned char *orders, gfp_t gfp) +{ + struct vcm_phys_list *lst, *n; + struct vcm_phys_part *out; + struct vcm_phys *phys; + unsigned count; + + if (WARN_ON((size & (PAGE_SIZE - 1)) || !size || !orders)) + return ERR_PTR(-EINVAL); + + lst = kmalloc(sizeof *lst, GFP_KERNEL); + if (!lst) + return ERR_PTR(-ENOMEM); + + lst->next = NULL; + lst->count = 0; + + count = vcm_phys_alloc_list(lst, size, flags, orders, gfp); + if (!count) + goto error; + + phys = kmalloc(sizeof *phys + count * sizeof *phys->parts, GFP_KERNEL); + if (!phys) + goto error; + + phys->free = vcm_phys_free; + phys->count = count; + phys->size = size; + + out = phys->parts; + do { + memcpy(out, lst->parts, lst->count * sizeof *out); + out += lst->count; + + n = lst->next; + kfree(lst); + lst = n; + } while (lst); + + return phys; + +error: + do { + vcm_phys_free_parts(lst->parts, lst->count); + + n = lst->next; + kfree(lst); + lst = n; + } while (lst); + + return ERR_PTR(-ENOMEM); +} +EXPORT_SYMBOL_GPL(__vcm_phys_alloc); + +static inline bool is_of_order(dma_addr_t size, unsigned order) +{ + return !(size & (((dma_addr_t)PAGE_SIZE << order) - 1)); +} + +static int +__vcm_phys_walk_part(dma_addr_t vaddr, const struct vcm_phys_part *part, + const unsigned char *orders, + int (*callback)(dma_addr_t vaddr, dma_addr_t paddr, + unsigned order, void *priv), void *priv, + unsigned *limit) +{ + resource_size_t size = part->size; + dma_addr_t paddr = part->start; + resource_size_t ps; + + while (!is_of_order(vaddr, *orders)) + ++orders; + while (!is_of_order(paddr, *orders)) + ++orders; + + ps = PAGE_SIZE << *orders; + for (; *limit && size; --*limit) { + int ret; + + while (ps > size) + ps = PAGE_SIZE << *++orders; + + ret = callback(vaddr, paddr, *orders, priv); + if (ret < 0) + return ret; + + ps = PAGE_SIZE << *orders; + vaddr += ps; + paddr += ps; + size -= ps; + } + + return 0; +} + +int vcm_phys_walk(dma_addr_t _vaddr, const struct vcm_phys *phys, + const unsigned char *orders, + int (*callback)(dma_addr_t vaddr, dma_addr_t paddr, + unsigned order, void *arg), + int (*recovery)(dma_addr_t vaddr, dma_addr_t paddr, + unsigned order, void *arg), + void *priv) +{ + unsigned limit = ~0; + int r = 0; + + if (WARN_ON(!phys || ((_vaddr | phys->size) & (PAGE_SIZE - 1)) || + !phys->size || !orders || !callback)) + return -EINVAL; + + for (;;) { + const struct vcm_phys_part *part = phys->parts; + unsigned count = phys->count; + dma_addr_t vaddr = _vaddr; + int ret = 0; + + for (; count && limit; --count, ++part) { + ret = __vcm_phys_walk_part(vaddr, part, orders, + callback, priv, &limit); + if (ret) + break; + + vaddr += part->size; + } + + if (r) + /* We passed error recovery */ + return r; + + /* + * Either operation suceeded or we were not provided + * with a recovery callback -- return. + */ + if (!ret || !recovery) + return ret; + + /* Switch to recovery */ + limit = ~0 - limit; + callback = recovery; + r = ret; + } +} +EXPORT_SYMBOL_GPL(vcm_phys_walk); + +#endif -- 1.6.2.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/