Am 10.11.2017 um 13:23 schrieb He, Roger: > > -----Original Message----- > From: Christian König [mailto:ckoenig.leichtzumerken at gmail.com] > Sent: Friday, November 10, 2017 8:02 PM > To: He, Roger <Hongbo.He at amd.com>; amd-gfx at lists.freedesktop.org > Subject: Re: [PATCH] drm/amd/amdgpu: not allow gtt size exceed system memory size > > Am 10.11.2017 um 12:33 schrieb Roger He: >> since sometimes VRAM size is bigger than system memory >> >> Change-Id: I5b14d18ed7a9f79810cc50c023ac9e240bddf101 >> Signed-off-by: Roger He <Hongbo.He at amd.com> >> --- >> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 11 ++++++++--- >> 1 file changed, 8 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c >> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c >> index cdbdf67..f103ccc 100644 >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c >> @@ -1330,9 +1330,14 @@ int amdgpu_ttm_init(struct amdgpu_device *adev) >> DRM_INFO("amdgpu: %uM of VRAM memory ready\n", >> (unsigned) (adev->mc.real_vram_size / (1024 * 1024))); >> >> - if (amdgpu_gtt_size == -1) >> - gtt_size = max((AMDGPU_DEFAULT_GTT_SIZE_MB << 20), >> - adev->mc.mc_vram_size); >> + if (amdgpu_gtt_size == -1) { >> + struct sysinfo si; >> + >> + si_meminfo(&si); >> + gtt_size = min(max((AMDGPU_DEFAULT_GTT_SIZE_MB << 20), >> + adev->mc.mc_vram_size), >> + ((uint64_t)si.totalram * si.mem_unit)); > TTM starts to try to swap things out when more than 50% of system memory are used, 75% is the default hard limit where it starts to block new allocations. > > So I would go with 75% here as well and code this as: > > gtt_size = AMDGPU_DEFAULT_GTT_SIZE_MB << 20; gtt_size = max(gtt_size, adev->mc.mc_vram_size); gtt_size = min(gtt_size, ((uint64_t)si.totalram * si.mem_unit) * 75 / 100); > > [Roger]: but in amdgpu_info_ioctl, for GTT size, reported to UMD already is *3/4 > case AMDGPU_INFO_MEMORY: { > > mem.gtt.heap_usage = > amdgpu_gtt_mgr_usage(&adev->mman.bdev.man[TTM_PL_TT]); > mem.gtt.max_allocation = mem.gtt.usable_heap_size * 3 / 4; > > So is it duplicated if *75/100 here? Good point, but that's only the maximum allocation size of a BO in GTT space, not how big GTT space itself is. And since this is only the available memory and since GTT isn't fragmented this is pretty much a complete useless value. We should probably change it to something like "total gtt size" - "size of pinned objects in gtt". But this is a separate problem I think, Christian. > > > Regards, > Christian. > >> + > >> + } >> else >> gtt_size = (uint64_t)amdgpu_gtt_size << 20; >> r = ttm_bo_init_mm(&adev->mman.bdev, TTM_PL_TT, gtt_size >> >> PAGE_SHIFT); >
