From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH 2/5] drm/gem: add shmem get/put page helpers Date: Mon, 8 Jul 2013 22:18:47 +0200 Message-ID: <20130708201847.GL18285@phenom.ffwll.local> References: <1373223531-19058-1-git-send-email-robdclark@gmail.com> <1373223531-19058-3-git-send-email-robdclark@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ee0-f50.google.com (mail-ee0-f50.google.com [74.125.83.50]) by gabe.freedesktop.org (Postfix) with ESMTP id 4850FE5C5F for ; Mon, 8 Jul 2013 13:18:48 -0700 (PDT) Received: by mail-ee0-f50.google.com with SMTP id d49so3046495eek.37 for ; Mon, 08 Jul 2013 13:18:47 -0700 (PDT) Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: Rob Clark Cc: dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org On Mon, Jul 08, 2013 at 02:56:31PM -0400, Rob Clark wrote: > On Mon, Jul 8, 2013 at 4:45 AM, Patrik Jakobsson > wrote: > > On Sun, Jul 7, 2013 at 8:58 PM, Rob Clark wrote: > >> Basically just extracting some code duplicated in gma500, omapdrm, udl, > >> and upcoming msm driver. > >> > >> Signed-off-by: Rob Clark > >> --- > >> drivers/gpu/drm/drm_gem.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++ > >> include/drm/drmP.h | 4 +++ > >> 2 files changed, 95 insertions(+) > >> > >> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c > >> index 443eeff..853dea6 100644 > >> --- a/drivers/gpu/drm/drm_gem.c > >> +++ b/drivers/gpu/drm/drm_gem.c > >> @@ -406,6 +406,97 @@ int drm_gem_create_mmap_offset(struct drm_gem_object *obj) > >> } > >> EXPORT_SYMBOL(drm_gem_create_mmap_offset); > >> > >> +/** > >> + * drm_gem_get_pages - helper to allocate backing pages for a GEM object > >> + * from shmem > >> + * @obj: obj in question > >> + * @gfpmask: gfp mask of requested pages > >> + */ > >> +struct page **drm_gem_get_pages(struct drm_gem_object *obj, gfp_t gfpmask) > >> +{ > >> + struct inode *inode; > >> + struct address_space *mapping; > >> + struct page *p, **pages; > >> + int i, npages; > >> + > >> + /* This is the shared memory object that backs the GEM resource */ > >> + inode = file_inode(obj->filp); > >> + mapping = inode->i_mapping; > >> + > >> + npages = obj->size >> PAGE_SHIFT; > > > > Theoretical issue, but what if obj->size is not page aligned? Perhaps put a > > roundup(obj->size, PAGE_SIZE) here? > > so, drm_gem_object_init() does have: > > BUG_ON((size & (PAGE_SIZE - 1)) != 0); > > so I was kinda assuming that we can count on the size already being > aligned. But I guess in case someone somehow bypasses > drm_gem_object_init() it wouldn't hurt to round up the size.. Would look funny to me to allow it in one place and not in another one. Maybe just throw a new WARN_ON in here (WARN since it's not fatal)? -Daniel > > BR, > -R > > >> + > >> + pages = drm_malloc_ab(npages, sizeof(struct page *)); > >> + if (pages == NULL) > >> + return ERR_PTR(-ENOMEM); > >> + > >> + gfpmask |= mapping_gfp_mask(mapping); > >> + > >> + for (i = 0; i < npages; i++) { > >> + p = shmem_read_mapping_page_gfp(mapping, i, gfpmask); > >> + if (IS_ERR(p)) > >> + goto fail; > >> + pages[i] = p; > >> + > >> + /* There is a hypothetical issue w/ drivers that require > >> + * buffer memory in the low 4GB.. if the pages are un- > >> + * pinned, and swapped out, they can end up swapped back > >> + * in above 4GB. If pages are already in memory, then > >> + * shmem_read_mapping_page_gfp will ignore the gfpmask, > >> + * even if the already in-memory page disobeys the mask. > >> + * > >> + * It is only a theoretical issue today, because none of > >> + * the devices with this limitation can be populated with > >> + * enough memory to trigger the issue. But this BUG_ON() > >> + * is here as a reminder in case the problem with > >> + * shmem_read_mapping_page_gfp() isn't solved by the time > >> + * it does become a real issue. > >> + * > >> + * See this thread: http://lkml.org/lkml/2011/7/11/238 > >> + */ > >> + BUG_ON((gfpmask & __GFP_DMA32) && > >> + (page_to_pfn(p) >= 0x00100000UL)); > >> + } > >> + > >> + return pages; > >> + > >> +fail: > >> + while (i--) > >> + page_cache_release(pages[i]); > >> + > >> + drm_free_large(pages); > >> + return ERR_CAST(p); > >> +} > >> +EXPORT_SYMBOL(drm_gem_get_pages); > >> + > >> +/** > >> + * drm_gem_put_pages - helper to free backing pages for a GEM object > >> + * @obj: obj in question > >> + * @pages: pages to free > >> + * @dirty: if true, pages will be marked as dirty > >> + * @accessed: if true, the pages will be marked as accessed > >> + */ > >> +void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages, > >> + bool dirty, bool accessed) > >> +{ > >> + int i, npages; > >> + > >> + npages = obj->size >> PAGE_SHIFT; > > > > Same thing here. > > > >> + > >> + for (i = 0; i < npages; i++) { > >> + if (dirty) > >> + set_page_dirty(pages[i]); > >> + > >> + if (accessed) > >> + mark_page_accessed(pages[i]); > >> + > >> + /* Undo the reference we took when populating the table */ > >> + page_cache_release(pages[i]); > >> + } > >> + > >> + drm_free_large(pages); > >> +} > >> +EXPORT_SYMBOL(drm_gem_put_pages); > >> + > >> /** Returns a reference to the object named by the handle. */ > >> struct drm_gem_object * > >> drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp, > >> diff --git a/include/drm/drmP.h b/include/drm/drmP.h > >> index 3cb1672..7ec3fa4 100644 > >> --- a/include/drm/drmP.h > >> +++ b/include/drm/drmP.h > >> @@ -1730,6 +1730,10 @@ void drm_gem_free_mmap_offset(struct drm_gem_object *obj); > >> int drm_gem_create_mmap_offset(struct drm_gem_object *obj); > >> int drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size); > >> > >> +struct page **drm_gem_get_pages(struct drm_gem_object *obj, gfp_t gfpmask); > >> +void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages, > >> + bool dirty, bool accessed); > >> + > >> struct drm_gem_object *drm_gem_object_lookup(struct drm_device *dev, > >> struct drm_file *filp, > >> u32 handle); > >> -- > >> 1.8.1.4 > > > > Looks good otherwise, so for all 5 patches: > > Reviewed-by: Patrik Jakobsson > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch