| Message ID | 1637104560-37432-2-git-send-email-quic_c_gdjako@quicinc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RFC,1/2] arm64: Add support for system cache memory type | expand |
On Wed, Nov 17, 2021 at 12:16 AM Georgi Djakov <quic_c_gdjako@quicinc.com> wrote: > > Instead of writing to WC cmdstream buffers that go all the way to the main > memory, let's use the system cache to improve the performance. > > Signed-off-by: Georgi Djakov <quic_c_gdjako@quicinc.com> > --- > drivers/gpu/drm/msm/msm_gem.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c > index 104fdfc14027..921a1c24721e 100644 > --- a/drivers/gpu/drm/msm/msm_gem.c > +++ b/drivers/gpu/drm/msm/msm_gem.c > @@ -214,7 +214,7 @@ void msm_gem_put_pages(struct drm_gem_object *obj) > static pgprot_t msm_gem_pgprot(struct msm_gem_object *msm_obj, pgprot_t prot) > { > if (msm_obj->flags & (MSM_BO_WC|MSM_BO_UNCACHED)) > - return pgprot_writecombine(prot); > + return pgprot_syscached(prot); > return prot; > } Based on the definition in patch 1, doesn't this mean that 32-bit kernels degrade from writecombined to uncached, making them a lot slower? My feeling about this series is that there should be a clearer definition of what exactly happens on systems with and without system cache. Arnd
diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c index 104fdfc14027..921a1c24721e 100644 --- a/drivers/gpu/drm/msm/msm_gem.c +++ b/drivers/gpu/drm/msm/msm_gem.c @@ -214,7 +214,7 @@ void msm_gem_put_pages(struct drm_gem_object *obj) static pgprot_t msm_gem_pgprot(struct msm_gem_object *msm_obj, pgprot_t prot) { if (msm_obj->flags & (MSM_BO_WC|MSM_BO_UNCACHED)) - return pgprot_writecombine(prot); + return pgprot_syscached(prot); return prot; }
Instead of writing to WC cmdstream buffers that go all the way to the main memory, let's use the system cache to improve the performance. Signed-off-by: Georgi Djakov <quic_c_gdjako@quicinc.com> --- drivers/gpu/drm/msm/msm_gem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)