gpu: ion: Add support for cached mappings that don't fault
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.
Change-Id: I227561f49e0f382a481728fb55ac5c930fc26025
Signed-off-by: Rebecca Schultz Zavin <rebecca@android.com>
Git-commit: 71545d66cc5afa4c930523810e62ba8ce391f621
Git-repo: https://android.googlesource.com/kernel/common
[mitchelh@codeaurora.org: merge conflicts in ion_buffer]
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
diff --git a/drivers/gpu/ion/ion.c b/drivers/gpu/ion/ion.c
index e068058..a5df149 100644
--- a/drivers/gpu/ion/ion.c
+++ b/drivers/gpu/ion/ion.c
@@ -227,7 +227,8 @@
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)
@@ -1320,7 +1321,8 @@
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);
@@ -1413,19 +1415,23 @@
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;
vma->vm_flags |= VM_MIXEDMAP;
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__);
@@ -1582,7 +1588,9 @@
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;
}