From: "Christian König" <christian.koenig@xxxxxxx> Date: 2020-04-21 15:41:27 To: 1587181464-114215-1-git-send-email-bernard@xxxxxxxx,Felix Kuehling <Felix.Kuehling@xxxxxxx>,Alex Deucher <alexander.deucher@xxxxxxx>,"David (ChunMing) Zhou" <David1.Zhou@xxxxxxx>,David Airlie <airlied@xxxxxxxx>,Daniel Vetter <daniel@xxxxxxxx>,amd-gfx@xxxxxxxxxxxxxxxxxxxxx,dri-devel@xxxxxxxxxxxxxxxxxxxxx,linux-kernel@xxxxxxxxxxxxxxx Cc: opensource.kernel@xxxxxxxx,Bernard Zhao <bernard@xxxxxxxx> Subject: Re: [PATCH V4] amdgpu: reduce no need mutex_lock area>Am 21.04.20 um 09:36 schrieb Bernard Zhao: >> Maybe we could reduce the mutex_lock(&mem->lock)`s protected code area, >> and no need to protect pr_debug. > >Well that change looks rather superfluous to me. > >This is for freeing memory which by definition can only be done once and >so the should be exactly zero contention on the lock except in a case of >an error. > >Regards, >Christian. > >> >> Signed-off-by: Bernard Zhao <bernard@xxxxxxxx> >> >> Changes since V1: >> *commit message improve >> >> Changes since V2: >> *move comment along with the mutex_unlock >> >> Changes since V3: >> *lock protect the if check, there is some possibility of multi-threaded >> racing modify. >> >> Link for V1: >> *https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fpatchwork%2Fpatch%2F1226588%2F&data=02%7C01%7Cchristian.koenig%40amd.com%7C9f2b2080f4174c421e4f08d7e5c6b899%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637230513976133424&sdata=6wezM%2F%2FjM5uuLblJejS9XFlE9DjWQ5zSt5PsqrfvCVo%3D&reserved=0 >> --- >> drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c >> index 327317c54f7c..549bdb429883 100644 >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c >> @@ -1289,9 +1289,9 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu( >> mutex_lock(&mem->lock); >> >> if (mem->mapped_to_gpu_memory > 0) { >> + mutex_unlock(&mem->lock); >> pr_debug("BO VA 0x%llx size 0x%lx is still mapped.\n", >> mem->va, bo_size); >> - mutex_unlock(&mem->lock); >> return -EBUSY; >> } >> > add Markus.Elfring in mail list Regards, Bernard _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
