On 23/03/17 06:26 PM, Julien Isorce wrote: > Hi Michel, > > When it happens, the main thread of our gl based app is stuck on a > ioctl(RADEON_CS). I set RADEON_THREAD=false to ease the debugging but > same thing happens if true. Other threads are only si_shader:0,1,2,3 and > are doing nothing, just waiting for jobs. I can also do sudo gdb -p > $(pidof Xorg) to block the X11 server, to make sure there is no ping > pong between 2 processes. All other processes are not loading > dri/radeonsi_dri.so . And adding a few traces shows that the above ioctl > call is looping for ever on > https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/ttm/ttm_bo.c#L819 > <https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/ttm/ttm_bo.c#L819> and > comes from > mesa https://cgit.freedesktop.org/mesa/mesa/tree/src/gallium/winsys/radeon/drm/radeon_drm_cs.c#n454 > . > > After adding even more traces I can see that the bo, which is being > indefinitely evicted, has the flag RADEON_GEM_NO_CPU_ACCESS. > And it gets 3 potential placements after calling "radeon_evict_flags". > 1: VRAM cpu inaccessible, fpfn is 65536 > 2: VRAM cpu accessible, fpfn is 0 > 3: GTT, fpfn is 0 > > And it looks like it continuously succeeds to move on the second > placement. So I might be wrong but it looks it is not even a ping pong > between VRAM accessible / not accessible, it just keeps being blited in > the CPU accessible part of the VRAM. Thanks for the detailed description! AFAICT this can only happen due to a silly mistake I made in this code. Does this fix it? diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c index 5c7cf644ba1d..37d68cd1f272 100644 --- a/drivers/gpu/drm/radeon/radeon_ttm.c +++ b/drivers/gpu/drm/radeon/radeon_ttm.c @@ -213,8 +213,8 @@ static void radeon_evict_flags(struct ttm_buffer_object *bo, rbo->placement.num_busy_placement = 0; for (i = 0; i < rbo->placement.num_placement; i++) { if (rbo->placements[i].flags & TTM_PL_FLAG_VRAM) { - if (rbo->placements[0].fpfn < fpfn) - rbo->placements[0].fpfn = fpfn; + if (rbo->placements[i].fpfn < fpfn) + rbo->placements[i].fpfn = fpfn; } else { rbo->placement.busy_placement = &rbo->placements[i]; -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer
