Am 03.12.19 um 14:22 schrieb Thomas Hellström (VMware):
From: Thomas Hellstrom thellstrom@vmware.com
This helper is used to align user-space buffer object addresses to huge page boundaries, minimizing the chance of alignment mismatch between user-space addresses and physical addresses.
Mhm, I'm wondering if that is really such a good idea.
Wouldn't it be sufficient if userspace uses MAP_HUGETLB?
Regards, Christian.
Cc: Andrew Morton akpm@linux-foundation.org Cc: Michal Hocko mhocko@suse.com Cc: "Matthew Wilcox (Oracle)" willy@infradead.org Cc: "Kirill A. Shutemov" kirill.shutemov@linux.intel.com Cc: Ralph Campbell rcampbell@nvidia.com Cc: "Jérôme Glisse" jglisse@redhat.com Cc: "Christian König" christian.koenig@amd.com Signed-off-by: Thomas Hellstrom thellstrom@vmware.com
drivers/gpu/drm/drm_file.c | 130 +++++++++++++++++++++++++++++++++++++ include/drm/drm_file.h | 5 ++ 2 files changed, 135 insertions(+)
diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c index ea34bc991858..e5b4024cd397 100644 --- a/drivers/gpu/drm/drm_file.c +++ b/drivers/gpu/drm/drm_file.c @@ -31,6 +31,8 @@
- OTHER DEALINGS IN THE SOFTWARE.
*/
+#include <uapi/asm/mman.h>
- #include <linux/dma-fence.h> #include <linux/module.h> #include <linux/pci.h>
@@ -41,6 +43,7 @@ #include <drm/drm_drv.h> #include <drm/drm_file.h> #include <drm/drm_print.h> +#include <drm/drm_vma_manager.h>
#include "drm_crtc_internal.h" #include "drm_internal.h" @@ -754,3 +757,130 @@ void drm_send_event(struct drm_device *dev, struct drm_pending_event *e) spin_unlock_irqrestore(&dev->event_lock, irqflags); } EXPORT_SYMBOL(drm_send_event);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE +/*
- drm_addr_inflate() attempts to construct an aligned area by inflating
- the area size and skipping the unaligned start of the area.
- adapted from shmem_get_unmapped_area()
- */
+static unsigned long drm_addr_inflate(unsigned long addr,
unsigned long len,unsigned long pgoff,unsigned long flags,unsigned long huge_size)+{
- unsigned long offset, inflated_len;
- unsigned long inflated_addr;
- unsigned long inflated_offset;
- offset = (pgoff << PAGE_SHIFT) & (huge_size - 1);
- if (offset && offset + len < 2 * huge_size)
return addr;- if ((addr & (huge_size - 1)) == offset)
return addr;- inflated_len = len + huge_size - PAGE_SIZE;
- if (inflated_len > TASK_SIZE)
return addr;- if (inflated_len < len)
return addr;- inflated_addr = current->mm->get_unmapped_area(NULL, 0, inflated_len,
0, flags);- if (IS_ERR_VALUE(inflated_addr))
return addr;- if (inflated_addr & ~PAGE_MASK)
return addr;- inflated_offset = inflated_addr & (huge_size - 1);
- inflated_addr += offset - inflated_offset;
- if (inflated_offset > offset)
inflated_addr += huge_size;- if (inflated_addr > TASK_SIZE - len)
return addr;- return inflated_addr;
+}
+/**
- drm_get_unmapped_area() - Get an unused user-space virtual memory area
- suitable for huge page table entries.
- @file: The struct file representing the address space being mmap()'d.
- @uaddr: Start address suggested by user-space.
- @len: Length of the area.
- @pgoff: The page offset into the address space.
- @flags: mmap flags
- @mgr: The address space manager used by the drm driver. This argument can
- probably be removed at some point when all drivers use the same
- address space manager.
- This function attempts to find an unused user-space virtual memory area
- that can accommodate the size we want to map, and that is properly
- aligned to facilitate huge page table entries matching actual
- huge pages or huge page aligned memory in buffer objects. Buffer objects
- are assumed to start at huge page boundary pfns (io memory) or be
- populated by huge pages aligned to the start of the buffer object
- (system- or coherent memory). Adapted from shmem_get_unmapped_area.
- Return: aligned user-space address.
- */
+unsigned long drm_get_unmapped_area(struct file *file,
unsigned long uaddr, unsigned long len,unsigned long pgoff, unsigned long flags,struct drm_vma_offset_manager *mgr)+{
- unsigned long addr;
- unsigned long inflated_addr;
- struct drm_vma_offset_node *node;
- if (len > TASK_SIZE)
return -ENOMEM;- /* Adjust mapping offset to be zero at bo start */
- drm_vma_offset_lock_lookup(mgr);
- node = drm_vma_offset_lookup_locked(mgr, pgoff, 1);
- if (node)
pgoff -= node->vm_node.start;- drm_vma_offset_unlock_lookup(mgr);
- addr = current->mm->get_unmapped_area(file, uaddr, len, pgoff, flags);
- if (IS_ERR_VALUE(addr))
return addr;- if (addr & ~PAGE_MASK)
return addr;- if (addr > TASK_SIZE - len)
return addr;- if (len < HPAGE_PMD_SIZE)
return addr;- if (flags & MAP_FIXED)
return addr;- /*
* Our priority is to support MAP_SHARED mapped hugely;* and support MAP_PRIVATE mapped hugely too, until it is COWed.* But if caller specified an address hint, respect that as before.*/- if (uaddr)
return addr;- inflated_addr = drm_addr_inflate(addr, len, pgoff, flags,
HPAGE_PMD_SIZE);- if (IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) &&
len >= HPAGE_PUD_SIZE)inflated_addr = drm_addr_inflate(inflated_addr, len, pgoff,flags, HPAGE_PUD_SIZE);- return inflated_addr;
+} +#else /* CONFIG_TRANSPARENT_HUGEPAGE */ +unsigned long drm_get_unmapped_area(struct file *file,
unsigned long uaddr, unsigned long len,unsigned long pgoff, unsigned long flags,struct drm_vma_offset_manager *mgr)+{
- return current->mm->get_unmapped_area(file, uaddr, len, pgoff, flags);
+} +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ +EXPORT_SYMBOL_GPL(drm_get_unmapped_area); diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h index 67af60bb527a..4719cc80d547 100644 --- a/include/drm/drm_file.h +++ b/include/drm/drm_file.h @@ -386,5 +386,10 @@ void drm_event_cancel_free(struct drm_device *dev, struct drm_pending_event *p); void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e); void drm_send_event(struct drm_device *dev, struct drm_pending_event *e); +struct drm_vma_offset_manager; +unsigned long drm_get_unmapped_area(struct file *file,
unsigned long uaddr, unsigned long len,unsigned long pgoff, unsigned long flags,struct drm_vma_offset_manager *mgr);#endif /* _DRM_FILE_H_ */