From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753750Ab3LMW05 (ORCPT ); Fri, 13 Dec 2013 17:26:57 -0500 Received: from mail-pb0-f51.google.com ([209.85.160.51]:36007 "EHLO mail-pb0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753728Ab3LMW0z (ORCPT ); Fri, 13 Dec 2013 17:26:55 -0500 From: John Stultz To: LKML Cc: Greg KH , Android Kernel Team , Sumit Semwal , Jesse Barker , Colin Cross , Rebecca Schultz Zavin , John Stultz Subject: [PATCH 031/115] gpu: ion: Add support for cached mappings that don't fault Date: Fri, 13 Dec 2013 14:24:05 -0800 Message-Id: <1386973529-4884-32-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1386973529-4884-1-git-send-email-john.stultz@linaro.org> References: <1386973529-4884-1-git-send-email-john.stultz@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rebecca Schultz Zavin We have found that faulting in the mappings for cached allocations has a significant performance impact and is only a benefit if only a small part of the buffer is touched by the cpu (an uncommon case for software rendering). This patch introduces a ION_FLAG_CACHED_NEEDS_SYNC which determines whether a mapping should be created by faulting or at mmap time. If this flag is set, userspace must manage the caches explictly using the SYNC ioctl. Signed-off-by: Rebecca Schultz Zavin [jstultz: modified patch to apply to staging directory] Signed-off-by: John Stultz --- drivers/staging/android/ion/ion.c | 28 ++++++++++++++++++---------- drivers/staging/android/ion/ion.h | 3 +++ 2 files changed, 21 insertions(+), 10 deletions(-) diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c index 3aeb41c..d1c7b84 100644 --- a/drivers/staging/android/ion/ion.c +++ b/drivers/staging/android/ion/ion.c @@ -164,7 +164,8 @@ static struct ion_buffer *ion_buffer_create(struct ion_heap *heap, return ERR_PTR(PTR_ERR(table)); } buffer->sg_table = table; - if (buffer->flags & ION_FLAG_CACHED) { + if (buffer->flags & ION_FLAG_CACHED && + !(buffer->flags & ION_FLAG_CACHED_NEEDS_SYNC)) { for_each_sg(buffer->sg_table->sgl, sg, buffer->sg_table->nents, i) { if (sg_dma_len(sg) == PAGE_SIZE) @@ -763,7 +764,8 @@ static void ion_buffer_sync_for_device(struct ion_buffer *buffer, pr_debug("%s: syncing for device %s\n", __func__, dev ? dev_name(dev) : "null"); - if (!(buffer->flags & ION_FLAG_CACHED)) + if (!(buffer->flags & ION_FLAG_CACHED) || + (buffer->flags & ION_FLAG_CACHED_NEEDS_SYNC)) return; mutex_lock(&buffer->lock); @@ -853,18 +855,22 @@ static int ion_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) return -EINVAL; } - if (buffer->flags & ION_FLAG_CACHED) { + if (buffer->flags & ION_FLAG_CACHED && + !(buffer->flags & ION_FLAG_CACHED_NEEDS_SYNC)) { vma->vm_private_data = buffer; vma->vm_ops = &ion_vma_ops; ion_vm_open(vma); - } else { - vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); - mutex_lock(&buffer->lock); - /* now map it to userspace */ - ret = buffer->heap->ops->map_user(buffer->heap, buffer, vma); - mutex_unlock(&buffer->lock); + return 0; } + if (!(buffer->flags & ION_FLAG_CACHED)) + vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); + + mutex_lock(&buffer->lock); + /* now map it to userspace */ + ret = buffer->heap->ops->map_user(buffer->heap, buffer, vma); + mutex_unlock(&buffer->lock); + if (ret) pr_err("%s: failure mapping buffer to userspace\n", __func__); @@ -1021,7 +1027,9 @@ static int ion_sync_for_device(struct ion_client *client, int fd) return -EINVAL; } buffer = dmabuf->priv; - ion_buffer_sync_for_device(buffer, NULL, DMA_BIDIRECTIONAL); + + dma_sync_sg_for_device(NULL, buffer->sg_table->sgl, + buffer->sg_table->nents, DMA_BIDIRECTIONAL); dma_buf_put(dmabuf); return 0; } diff --git a/drivers/staging/android/ion/ion.h b/drivers/staging/android/ion/ion.h index 83baa38..072d64d 100644 --- a/drivers/staging/android/ion/ion.h +++ b/drivers/staging/android/ion/ion.h @@ -50,6 +50,9 @@ enum ion_heap_type { cached, ion will do cache maintenance when the buffer is mapped for dma */ +#define ION_FLAG_CACHED_NEEDS_SYNC 2 /* mappings of this buffer will created + at mmap time, if this is set + caches must be managed manually */ #ifdef __KERNEL__ struct ion_device; -- 1.8.3.2