Linaro-mm-sig

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5 participants
2541 discussions

Re: [Linaro-mm-sig] [PATCH] dma-buf: add support for compat ioctl

by Daniel Vetter

On Tue, Feb 21, 2017 at 4:08 PM, Christian König <deathsimple(a)vodafone.de> wrote: > Am 21.02.2017 um 15:55 schrieb Marek Szyprowski: >> >> Dear All, >> >> On 2017-02-21 15:37, Marek Szyprowski wrote: >>> >>> Hi Christian, >>> >>> On 2017-02-21 14:59, Christian König wrote: >>>> >>>> Am 21.02.2017 um 14:21 schrieb Marek Szyprowski: >>>>> >>>>> Add compat ioctl support to dma-buf. This lets one to use >>>>> DMA_BUF_IOCTL_SYNC >>>>> ioctl from 32bit application on 64bit kernel. Data structures for both >>>>> 32 >>>>> and 64bit modes are same, so there is no need for additional >>>>> translation >>>>> layer. >>>> >>>> >>>> Well I might be wrong, but IIRC compat_ioctl was just optional and if >>>> not specified unlocked_ioctl was called instead. >>>> >>>> If that is true your patch wouldn't have any effect at all. >>> >>> >>> Well, then why I got -ENOTTY in the 32bit test app for this ioctl on >>> 64bit ARM64 kernel without this patch? >>> >> >> I've checked in fs/compat_ioctl.c, I see no fallback in >> COMPAT_SYSCALL_DEFINE3, >> so one has to provide compat_ioctl callback to have ioctl working with >> 32bit >> apps. > > > Then my memory cheated on me. > > In this case the patch is Reviewed-by: Christian König > <christian.koenig(a)amd.com>. Since you have commit rights for drm-misc, care to push this to drm-misc-next-fixes pls? Also I think this warrants a cc: stable, clearly an obvious screw-up in creating this api on our side :( So feel free to smash my ack on the patch. Thanks, Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch

7 years, 10 months

Re: [Linaro-mm-sig] [RFCv3][PATCH 3/5] arm64: Implement ARCH_HAS_FORCE_CACHE

by Laura Abbott

On 02/20/2017 10:05 PM, Chen Feng wrote: > Hi Laura, > > When we enable kernel v4.4 or newer version on our platform, we meet the issue > of flushing cache without reference device. It seems that this patch set is > a solution. I'm curious the progress of the discussion. Do you have any plan > to fix it in v4.4 and newer kernel verison? > No, I've abandoned this approach based on feedback. The APIs had too much potential for incorrect usage. I'm ripping out the implicit caching in Ion and switching it to a model where there should always be a device available. What's your use case where you don't have a device structure? Thanks, Laura > On 2016/9/14 2:41, Laura Abbott wrote: >> On 09/13/2016 08:14 AM, Will Deacon wrote: >>> On Tue, Sep 13, 2016 at 08:02:20AM -0700, Laura Abbott wrote: >>>> On 09/13/2016 02:19 AM, Will Deacon wrote: >>>>> On Mon, Sep 12, 2016 at 02:32:56PM -0700, Laura Abbott wrote: >>>>>> >>>>>> arm64 may need to guarantee the caches are synced. Implement versions of >>>>>> the kernel_force_cache API to allow this. >>>>>> >>>>>> Signed-off-by: Laura Abbott <labbott(a)redhat.com> >>>>>> --- >>>>>> v3: Switch to calling cache operations directly instead of relying on >>>>>> DMA mapping. >>>>>> --- >>>>>> arch/arm64/include/asm/cacheflush.h | 8 ++++++++ >>>>>> arch/arm64/mm/cache.S | 24 ++++++++++++++++++++---- >>>>>> arch/arm64/mm/flush.c | 11 +++++++++++ >>>>>> 3 files changed, 39 insertions(+), 4 deletions(-) >>>>> >>>>> I'm really hesitant to expose these cache routines as an API solely to >>>>> support a driver sitting in staging/. I appreciate that there's a chicken >>>>> and egg problem here, but we *really* don't want people using these routines >>>>> in preference to the DMA API, and I fear that we'll simply grow a bunch >>>>> more users of these things if we promote it as an API like you're proposing. >>>>> >>>>> Can the code not be contained under staging/, as part of ion? >>>>> >>>> >>>> I proposed that in V1 and it was suggested I make it a proper API >>>> >>>> http://www.mail-archive.com/driverdev-devel@linuxdriverproject.org/msg47654… >>>> http://www.mail-archive.com/driverdev-devel@linuxdriverproject.org/msg47672… >>> >>> :/ then I guess we're in disagreement. If ion really needs this stuff >>> (which I don't fully grok), perhaps we should be exposing something at >>> a higher level from the architecture, so it really can't be used for >>> anything other than ion. >> >> I talked/complained about this at a past plumbers. The gist is that Ion >> ends up acting as a fake DMA layer for clients. It doesn't match nicely >> because clients can allocate both coherent and non-coherent memory. >> Trying to use dma_map doesn't work because a) a device for coherency isn't >> known at allocation time b) it kills performance. Part of the motivation >> for taking this approach is to avoid the need to rework the existing >> Android userspace and keep the existing behavior, as terrible as it >> is. Having Ion out of staging and not actually usable isn't helpful. >> >> I'll give this all some more thought and hopefully have one or two more >> proposals before Connect/Plumbers. >> >>> >>> Will >>> >> >> Thanks, >> Laura >> _______________________________________________ >> Linaro-mm-sig mailing list >> Linaro-mm-sig(a)lists.linaro.org >> https://lists.linaro.org/mailman/listinfo/linaro-mm-sig > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel(a)lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >

7 years, 10 months

Re: [Linaro-mm-sig] [PATCH] dma-buf: add support for compat ioctl

by Marek Szyprowski

Hi Christian, On 2017-02-21 14:59, Christian König wrote: > Am 21.02.2017 um 14:21 schrieb Marek Szyprowski: >> Add compat ioctl support to dma-buf. This lets one to use >> DMA_BUF_IOCTL_SYNC >> ioctl from 32bit application on 64bit kernel. Data structures for >> both 32 >> and 64bit modes are same, so there is no need for additional translation >> layer. > > Well I might be wrong, but IIRC compat_ioctl was just optional and if > not specified unlocked_ioctl was called instead. > > If that is true your patch wouldn't have any effect at all. Well, then why I got -ENOTTY in the 32bit test app for this ioctl on 64bit ARM64 kernel without this patch? Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland

7 years, 10 months

[PATCH] dma-buf: add support for compat ioctl

by Marek Szyprowski

Add compat ioctl support to dma-buf. This lets one to use DMA_BUF_IOCTL_SYNC ioctl from 32bit application on 64bit kernel. Data structures for both 32 and 64bit modes are same, so there is no need for additional translation layer. Signed-off-by: Marek Szyprowski <m.szyprowski(a)samsung.com> --- drivers/dma-buf/dma-buf.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 718f832a5c71..0007b792827b 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -325,6 +325,9 @@ static long dma_buf_ioctl(struct file *file, .llseek = dma_buf_llseek, .poll = dma_buf_poll, .unlocked_ioctl = dma_buf_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = dma_buf_ioctl, +#endif }; /* -- 1.9.1

7 years, 10 months

[PATCH] allow buffers allocation with DMABUF memory type

by Benjamin Gaignard

Until now the only way to make the driver allocate buffers and share them using dma_buf was to use V4L2_MEMORY_MMAP memory type. Use of MMAP memory type is a problem because vb2 never call dma_buf_map_attachment() to attach itself while queuing the buffer so dma_buf importer will not know that another device use this buffer. This patch allow to allocate buffer even for DMABUF memory type and correctly manage dma_buf buffer attachment. vb2_mem_ops attach_dmabuf() prototype has been changed to be able to distinguish if the attachment is done on a already existing buffer or on imported one. Signed-off-by: Benjamin Gaignard <benjamin.gaignard(a)linaro.org> --- drivers/media/v4l2-core/videobuf2-core.c | 76 ++++++++++++++++++++++++-- drivers/media/v4l2-core/videobuf2-dma-contig.c | 10 ++-- drivers/media/v4l2-core/videobuf2-dma-sg.c | 8 ++- drivers/media/v4l2-core/videobuf2-vmalloc.c | 8 ++- include/media/videobuf2-core.h | 5 +- 5 files changed, 91 insertions(+), 16 deletions(-) diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index 1329dcc..c5968aa 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -337,6 +337,67 @@ static void __setup_offsets(struct vb2_queue *q, unsigned int n) } /** + * __setup_dmabufs() - setup dmabuf fd for every plane in + * every buffer on the queue + */ +static void __setup_dmabufs(struct vb2_queue *q, unsigned int n) +{ + unsigned int buffer, plane; + struct vb2_buffer *vb; + struct vb2_plane *vb_plane; + struct dma_buf *dbuf; + void *mem_priv; + int fd; + int write = !V4L2_TYPE_IS_OUTPUT(q->type); + int flags = write ? O_WRONLY : O_RDONLY; + + for (buffer = q->num_buffers; buffer < q->num_buffers + n; ++buffer) { + vb = q->bufs[buffer]; + if (!vb) + continue; + + for (plane = 0; plane < vb->num_planes; ++plane) { + vb_plane = &vb->planes[plane]; + + dbuf = call_ptr_memop(vb, get_dmabuf, + vb_plane->mem_priv, + flags & O_ACCMODE); + if (IS_ERR_OR_NULL(dbuf)) { + dprintk(1, "Failed to export buffer %d, " \ + "plane %d\n", buffer, plane); + continue; + } + + fd = dma_buf_fd(dbuf, flags & ~O_ACCMODE); + if (fd < 0) { + dprintk(3, "buffer %d, plane %d failed " \ + "to export (%d)\n", buffer, plane, fd); + dma_buf_put(dbuf); + continue; + } + + /* Acquire each plane's memory */ + mem_priv = call_ptr_memop(vb, attach_dmabuf, + q->alloc_ctx[plane], dbuf, + vb->v4l2_planes[plane].length, + write, vb_plane->mem_priv); + if (IS_ERR(mem_priv)) { + dprintk(1, "Buffer %d plane %d failed "\ + "to attach dmabuf\n", buffer, plane); + dma_buf_put(dbuf); + continue; + } + + vb_plane->dbuf = dbuf; + vb->v4l2_planes[plane].m.fd = fd; + + dprintk(3, "Buffer %d, plane %d fd %x\n", + buffer, plane, fd); + } + } +} + +/** * __vb2_queue_alloc() - allocate videobuf buffer structures and (for MMAP type) * video buffer memory for all buffers/planes on the queue and initializes the * queue @@ -369,8 +430,9 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum v4l2_memory memory, vb->v4l2_buf.type = q->type; vb->v4l2_buf.memory = memory; - /* Allocate video buffer memory for the MMAP type */ - if (memory == V4L2_MEMORY_MMAP) { + /* Allocate video buffer memory for the MMAP and DMABUF types */ + if (memory == V4L2_MEMORY_MMAP || + memory == V4L2_MEMORY_DMABUF) { ret = __vb2_buf_mem_alloc(vb); if (ret) { dprintk(1, "failed allocating memory for " @@ -400,6 +462,9 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum v4l2_memory memory, if (memory == V4L2_MEMORY_MMAP) __setup_offsets(q, buffer); + if (memory == V4L2_MEMORY_DMABUF) + __setup_dmabufs(q, buffer); + dprintk(1, "allocated %d buffers, %d plane(s) each\n", buffer, num_planes); @@ -859,7 +924,7 @@ static int __verify_memory_type(struct vb2_queue *q, * to be used during streaming, * 4) allocates internal buffer structures (struct vb2_buffer), according to * the agreed parameters, - * 5) for MMAP memory type, allocates actual video memory, using the + * 5) for MMAP and DMABUF memory types, allocates actual video memory, using the * memory handling/allocation routines provided during queue initialization * * If req->count is 0, all the memory will be freed instead. @@ -885,7 +950,8 @@ static int __reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req) * are not in use and can be freed. */ mutex_lock(&q->mmap_lock); - if (q->memory == V4L2_MEMORY_MMAP && __buffers_in_use(q)) { + if ((q->memory == V4L2_MEMORY_MMAP || + q->memory == V4L2_MEMORY_DMABUF) && __buffers_in_use(q)) { mutex_unlock(&q->mmap_lock); dprintk(1, "memory in use, cannot free\n"); return -EBUSY; @@ -1540,7 +1606,7 @@ static int __qbuf_dmabuf(struct vb2_buffer *vb, const struct v4l2_buffer *b) /* Acquire each plane's memory */ mem_priv = call_ptr_memop(vb, attach_dmabuf, q->alloc_ctx[plane], - dbuf, planes[plane].length, dma_dir); + dbuf, planes[plane].length, dma_dir, NULL); if (IS_ERR(mem_priv)) { dprintk(1, "failed to attach dmabuf\n"); ret = PTR_ERR(mem_priv); diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c index b481d20..8dc945e 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c @@ -793,7 +793,7 @@ static void vb2_dc_detach_dmabuf(void *mem_priv) struct vb2_dc_buf *buf = mem_priv; /* if vb2 works correctly you should never detach mapped buffer */ - if (WARN_ON(buf->dma_addr)) + if (WARN_ON(buf->dma_sgt)) vb2_dc_unmap_dmabuf(buf); /* detach this attachment */ @@ -802,16 +802,18 @@ static void vb2_dc_detach_dmabuf(void *mem_priv) } static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf, - unsigned long size, enum dma_data_direction dma_dir) + unsigned long size, enum dma_data_direction dma_dir, void *buf_priv) { struct vb2_dc_conf *conf = alloc_ctx; - struct vb2_dc_buf *buf; + struct vb2_dc_buf *buf = buf_priv; struct dma_buf_attachment *dba; if (dbuf->size < size) return ERR_PTR(-EFAULT); - buf = kzalloc(sizeof(*buf), GFP_KERNEL); + if (!buf) + buf = kzalloc(sizeof(*buf), GFP_KERNEL); + if (!buf) return ERR_PTR(-ENOMEM); diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c index b1838ab..b9855fd 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-sg.c +++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c @@ -667,16 +667,18 @@ static void vb2_dma_sg_detach_dmabuf(void *mem_priv) } static void *vb2_dma_sg_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf, - unsigned long size, enum dma_data_direction dma_dir) + unsigned long size, enum dma_data_direction dma_dir, void *buf_priv) { struct vb2_dma_sg_conf *conf = alloc_ctx; - struct vb2_dma_sg_buf *buf; + struct vb2_dma_sg_buf *buf = buf_priv; struct dma_buf_attachment *dba; if (dbuf->size < size) return ERR_PTR(-EFAULT); - buf = kzalloc(sizeof(*buf), GFP_KERNEL); + if (!buf) + buf = kzalloc(sizeof(*buf), GFP_KERNEL); + if (!buf) return ERR_PTR(-ENOMEM); diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c b/drivers/media/v4l2-core/videobuf2-vmalloc.c index bcde885..373294c 100644 --- a/drivers/media/v4l2-core/videobuf2-vmalloc.c +++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c @@ -416,14 +416,16 @@ static void vb2_vmalloc_detach_dmabuf(void *mem_priv) } static void *vb2_vmalloc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf, - unsigned long size, enum dma_data_direction dma_dir) + unsigned long size, enum dma_data_direction dma_dir, void *buf_priv) { - struct vb2_vmalloc_buf *buf; + struct vb2_vmalloc_buf *buf = buf_priv; if (dbuf->size < size) return ERR_PTR(-EFAULT); - buf = kzalloc(sizeof(*buf), GFP_KERNEL); + if (!buf) + buf = kzalloc(sizeof(*buf), GFP_KERNEL); + if (!buf) return ERR_PTR(-ENOMEM); diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index a5790fd..374b26b 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -49,6 +49,8 @@ struct vb2_threadio_data; * used for DMABUF memory types; alloc_ctx is the alloc context * dbuf is the shared dma_buf; returns NULL on failure; * allocator private per-buffer structure on success; + * if private per-buffer structure is provided reuse it + * instead of allocating a new one. * this needs to be used for further accesses to the buffer. * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF * buffer is no longer used; the buf_priv argument is the @@ -98,7 +100,8 @@ struct vb2_mem_ops { void *(*attach_dmabuf)(void *alloc_ctx, struct dma_buf *dbuf, unsigned long size, - enum dma_data_direction dma_dir); + enum dma_data_direction dma_dir, + void *buf_priv); void (*detach_dmabuf)(void *buf_priv); int (*map_dmabuf)(void *buf_priv); void (*unmap_dmabuf)(void *buf_priv); -- 1.9.1

7 years, 11 months

[PATCH] dma-buf: Wait on the reservation object when sync'ing before CPU access

by Chris Wilson

Rendering operations to the dma-buf are tracked implicitly via the reservation_object (dmabuf->resv). This is used to allow poll() to wait upon outstanding rendering (or just query the current status of rendering). The dma-buf sync ioctl allows userspace to prepare the dma-buf for CPU access, which should include waiting upon rendering. (Some drivers may need to do more work to ensure that the dma-buf mmap is coherent as well as complete.) Signed-off-by: Chris Wilson <chris(a)chris-wilson.co.uk> Cc: Sumit Semwal <sumit.semwal(a)linaro.org> Cc: Daniel Vetter <daniel.vetter(a)ffwll.ch> Cc: linux-media(a)vger.kernel.org Cc: dri-devel(a)lists.freedesktop.org Cc: linaro-mm-sig(a)lists.linaro.org Cc: linux-kernel(a)vger.kernel.org --- I'm wondering whether it makes sense just to always do the wait first. It is one of the first operations every driver has to make. A driver that wants to implement it differently (e.g. they can special case native waits) will still require a wait on the reservation object to finish external rendering. -Chris --- drivers/dma-buf/dma-buf.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index ddaee60ae52a..123f14b8e882 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -586,6 +586,22 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, } EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); +static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf, + enum dma_data_direction direction) +{ + bool write = (direction == DMA_BIDIRECTIONAL || + direction == DMA_TO_DEVICE); + struct reservation_object *resv = dma_buf->resv; + long ret; + + /* Wait on any implicit rendering fences */ + ret = reservation_object_wait_timeout_rcu(resv, write, true, + MAX_SCHEDULE_TIMEOUT); + if (ret < 0) + return ret; + + return 0; +} /** * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the @@ -607,6 +623,8 @@ int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, if (dmabuf->ops->begin_cpu_access) ret = dmabuf->ops->begin_cpu_access(dmabuf, direction); + else + ret = __dma_buf_begin_cpu_access(dmabuf, direction); return ret; } -- 2.8.1

8 years

[RFC PATCH 0/4] Ion caching (yet again) proof of concept

by Laura Abbott

Hi, I've been (once again) looking at alternate caching models for Ion. Part of this work is also to make Ion fit better in to the dma_buf model. Ion is a bit unusual for dma_buf. Most drivers that support dma_buf have two parts: exporting buffers that a driver allocates and importing buffers allocated elsewhere for use by the driver. Ion is basically designed to export only and not import buffers from other drivers (the need for import is also on my TODO list) Even more unusual, there is no actual 'driver' to map into. Ion currently does nothing except pass back the same sg_table each time without calling dma_map. The description of the .map_dma_buf function in dma_buf_ops * @map_dma_buf: returns list of scatter pages allocated, increases usecount * of the buffer. Requires atleast one attach to be called * before. Returned sg list should already be mapped into * _device_ address space. This call may sleep. May also return * -EINTR. Should return -EINVAL if attach hasn't been called yet. So Ion is definitely not doing this correctly. This ties back into correcting the caching model. If we call dma_map_sg/dma_unmap_sg with begin_cpu_access, this should be enough to allow the caches to always be properly synchronized and means we can drop the various dma_sync calls floating around. This is going to violate one of the big fat comments in ion_buffer_create /* * this will set up dma addresses for the sglist -- it is not * technically correct as per the dma api -- a specific * device isn't really taking ownership here. However, in practice on * our systems the only dma_address space is physical addresses. * Additionally, we can't afford the overhead of invalidating every * allocation via dma_map_sg. The implicit contract here is that * memory coming from the heaps is ready for dma, ie if it has a * cached mapping that mapping has been invalidated */ for_each_sg(buffer->sg_table->sgl, sg, buffer->sg_table->nents, i) { sg_dma_address(sg) = sg_phys(sg); sg_dma_len(sg) = sg->length; } The overhead of invalidating is a valid concern. I'm hoping that the architecture has either evolved such that this won't be a problem or we can figure out some clever use of DMA_ATTR_SKIP_CPU_SYNC. As part of this, I'm considering dropping the fault synchronization. If we have explicit use begin_cpu_access and use of the dma_buf sync ioctls, I don't think it should be necessary. I have a 'pre-RFC' tree at https://pagure.io/kernel-ion/branch/ion_cache_proof_dec14 Yes, the patches are not bisectable and there is more to be done. These have been compile tested only and haven't been hooked up to anything to actually run (another actually big TODO). I'm mostly looking for feedback if this looks like the right direction and if there are going to be major problems with this approach. I don't actually anticipate this getting merged into drivers/staging/android/ion but this is the easiest way to continue discussion. Thanks, Laura Laura Abbott (4): staging: android: ion: Some cleanup staging: android: ion: Duplicate sg_table staging: android: ion: Remove page faulting support staging: android: ion: Call dma_map_sg for syncing and mapping drivers/staging/android/ion/ion-ioctl.c | 6 - drivers/staging/android/ion/ion.c | 251 ++++++++---------------- drivers/staging/android/ion/ion.h | 5 +- drivers/staging/android/ion/ion_carveout_heap.c | 16 +- drivers/staging/android/ion/ion_chunk_heap.c | 15 +- drivers/staging/android/ion/ion_cma_heap.c | 5 +- drivers/staging/android/ion/ion_page_pool.c | 3 - drivers/staging/android/ion/ion_priv.h | 4 +- drivers/staging/android/ion/ion_system_heap.c | 14 +- 9 files changed, 90 insertions(+), 229 deletions(-) -- 2.7.4

8 years

Follow up on Ion from LPC

by Laura Abbott

Hi, At LPC, I proposed a moratorium on new Ion features because of issues preventing Ion ever moving out of staging. Among other problems, the Ion caching model hasn't made much progress to a solution that is widely accepted and there are still problems with devicetree support. There were no strong objections to this proposal so I propose continuing with a moratorium for at least the next 6 months to a year to actually work on a new architecture. If this hasn't made much progress by then I plan to hand off Ion to someone else to try other approaches. There's been some discussion about a Unix Device Memory Allocator https://github.com/cubanismo/allocator . Ideally, this would be a complete replacement for Ion. This means capturing Ion or Ion-like requirements. The current proposal mostly focuses on userspace requirements and assumes Ion is just acting as an enumerator of various memory to allocate. This is a good direction. Ideally some of the Ion kernel code could be leveraged for a 'generic device memory allocator'. This device allocator should also be support use cases such as the SMAF (secure memory allocation framework) which has also been a work in progress. One of the big open problems, as mentioned above, is the caching model. Specifying an uncached buffer at allocation time requires doing cache operations outside of the DMA framework which makes a bunch of maintainers unhappy. None of the arguments I've given for justification have really stuck which is a good sign that Ion should probably not be doing cache operations. If we ignore the Ion page pooling feature, this could be fixed by requiring that drivers call dma_buf_map and calling dma_map there. This gets tricker when drivers want to call mmap from userspace before passing the buffer down to ensure coherency. This model will need some more thought and possibly integration with Android. I'd like to keep using linaro-mm-sig as a mailing list for Ion discussion as well as drivers-devel. If it would help to have another place for tracking/discussion I can see about setting that up as well. Thanks, Laura

8 years, 1 month

[PATCH -next] dma-buf/sw_sync: fix non static symbol warning

by Wei Yongjun

From: Wei Yongjun <weiyongjun1(a)huawei.com> Fixes the following sparse warning: drivers/dma-buf/sw_sync.c:87:22: warning: symbol 'sync_timeline_create' was not declared. Should it be static? Signed-off-by: Wei Yongjun <weiyongjun1(a)huawei.com> --- drivers/dma-buf/sw_sync.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c index 82e0ca4..7aa4d7b 100644 --- a/drivers/dma-buf/sw_sync.c +++ b/drivers/dma-buf/sw_sync.c @@ -84,7 +84,7 @@ static inline struct sync_pt *dma_fence_to_sync_pt(struct dma_fence *fence) * Creates a new sync_timeline. Returns the sync_timeline object or NULL in * case of error. */ -struct sync_timeline *sync_timeline_create(const char *name) +static struct sync_timeline *sync_timeline_create(const char *name) { struct sync_timeline *obj;

8 years, 2 months

[RFC 0/6] Module for tracking/accounting shared memory buffers

by Ruchi Kandoi

This patchstack introduces a new "memtrack" module for tracking and accounting memory exported to userspace as shared buffers, like dma-buf fds or GEM handles. Any process holding a reference to these buffers will keep the kernel from reclaiming its backing pages. mm counters don't provide a complete picture of these allocations, since they only account for pages that are mapped into a process's address space. This problem is especially bad for systems like Android that use dma-buf fds to share graphics and multimedia buffers between processes: these allocations are often large, have complex sharing patterns, and are rarely mapped into every process that holds a reference to them. memtrack maintains a per-process list of shared buffer references, which is exported to userspace as /proc/[pid]/memtrack. Buffers can be optionally "tagged" with a short string: for example, Android userspace would use this tag to identify whether buffers were allocated on behalf of the camera stack, GL, etc. memtrack also exports the VMAs associated with these buffers so that pages already included in the process's mm counters aren't double-counted. Shared-buffer allocators can hook into memtrack by embedding struct memtrack_buffer in their buffer metadata, calling memtrack_buffer_{init,remove} at buffer allocation and free time, and memtrack_buffer_{install,uninstall} when a userspace process takes or drops a reference to the buffer. For fd-backed buffers like dma-bufs, hooks in fdtable.c and fork.c automatically notify memtrack when references are added or removed from a process's fd table. This patchstack adds memtrack hooks into dma-buf and ion. If there's upstream interest in memtrack, it can be extended to other memory allocators as well, such as GEM implementations. Greg Hackmann (1): drivers: staging: ion: add ION_IOC_TAG ioctl Ruchi Kandoi (5): fs: add installed and uninstalled file_operations drivers: misc: add memtrack dma-buf: add memtrack support memtrack: Adds the accounting to keep track of all mmaped/unmapped pages. memtrack: Add memtrack accounting for forked processes. drivers/android/binder.c | 4 +- drivers/dma-buf/dma-buf.c | 37 +++ drivers/misc/Kconfig | 16 + drivers/misc/Makefile | 1 + drivers/misc/memtrack.c | 516 ++++++++++++++++++++++++++++++++ drivers/staging/android/ion/ion-ioctl.c | 17 ++ drivers/staging/android/ion/ion.c | 60 +++- drivers/staging/android/ion/ion_priv.h | 2 + drivers/staging/android/uapi/ion.h | 25 ++ fs/file.c | 38 ++- fs/open.c | 2 +- fs/proc/base.c | 4 + include/linux/dma-buf.h | 5 + include/linux/fdtable.h | 4 +- include/linux/fs.h | 2 + include/linux/memtrack.h | 130 ++++++++ include/linux/mm.h | 3 + include/linux/sched.h | 3 + kernel/fork.c | 23 +- 19 files changed, 875 insertions(+), 17 deletions(-) create mode 100644 drivers/misc/memtrack.c create mode 100644 include/linux/memtrack.h -- 2.8.0.rc3.226.g39d4020

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