If clwb is available on the system, use it in drm_clflush_page. If clwb is not available, fall back to clflushopt if you can. If clflushopt is not supported, fall all the way back to clflush.
Signed-off-by: Ross Zwisler ross.zwisler@linux.intel.com Cc: H Peter Anvin h.peter.anvin@intel.com Cc: Ingo Molnar mingo@kernel.org Cc: Thomas Gleixner tglx@linutronix.de Cc: David Airlie airlied@linux.ie Cc: dri-devel@lists.freedesktop.org Cc: x86@kernel.org --- drivers/gpu/drm/drm_cache.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c index a6b6906..aad9d82 100644 --- a/drivers/gpu/drm/drm_cache.c +++ b/drivers/gpu/drm/drm_cache.c @@ -34,9 +34,9 @@ #if defined(CONFIG_X86)
/* - * clflushopt is an unordered instruction which needs fencing with mfence or - * sfence to avoid ordering issues. For drm_clflush_page this fencing happens - * in the caller. + * clwb and clflushopt are unordered instructions which need fencing with + * mfence or sfence to avoid ordering issues. For drm_clflush_page this + * fencing happens in the caller. */ static void drm_clflush_page(struct page *page) @@ -50,7 +50,7 @@ drm_clflush_page(struct page *page)
page_virtual = kmap_atomic(page); for (i = 0; i < PAGE_SIZE; i += size) - clflushopt(page_virtual + i); + clwb(page_virtual + i); kunmap_atomic(page_virtual); }