Change eats memory on my server

[Eli Cohen]

On Mon, Jan 18, 2021 at 08:54:07AM +0100, Thomas Zimmermann wrote:
> Hi
> 
> Am 18.01.21 um 08:43 schrieb Christian König:
> > Hi Eli,
> > 
> > have you already tried using kmemleak?
> > 
> > This sounds like a leak of memory allocated using kmalloc(), so kmemleak
> > should be able to catch it.
> 
> I have an idea what happens here. When the refcount is 0 in kmap, a new page
> mapping for the BO is being established. But VRAM helpers unmap the previous
> pages only on BO moves or frees; not in kunmap. So the old mapping might
> still be around. I'll send out a test patch later today.
> 

Great! Looking forward to test it.

> Best regards
> Thomas
> 
> > 
> > Regards,
> > Christian.
> > 
> > Am 17.01.21 um 06:08 schrieb Eli Cohen:
> > > On Fri, Jan 15, 2021 at 10:03:50AM +0100, Thomas Zimmermann wrote:
> > > > Could you please double-check that 3fb91f56aea4 ("drm/udl: Retrieve USB
> > > > device from struct drm_device.dev") works correctly
> > > Checked again, it does not seem to leak.
> > > 
> > > > and that 823efa922102
> > > > ("drm/cma-helper: Remove empty drm_gem_cma_prime_vunmap()") is broken?
> > > > 
> > > Yes, this one leaks, as does the one preceding it:
> > > 
> > > 1086db71a1db ("drm/vram-helper: Remove invariant parameters from
> > > internal kmap function")
> > > > For one of the broken commits, could you please send us the output of
> > > > 
> > > >    dmesg | grep -i drm
> > > > 
> > > > after most of the memory got leaked?
> > > > 
> > > I ran the following script in the shell:
> > > 
> > > while true; do cat /proc/meminfo | grep MemFree:; sleep 5; done
> > > 
> > > and this is what I saw before I got disconnected from the shell:
> > > 
> > > MemFree:          148208 kB
> > > MemFree:          148304 kB
> > > MemFree:          146660 kB
> > > Connection to nps-server-24 closed by remote host.
> > > Connection to nps-server-24 closed.
> > > 
> > > 
> > > I also mointored the output of dmesg | grep -i drm
> > > The last output I was able to save on disk is this:
> > > 
> > > [   46.140720] ast 0000:03:00.0: [drm] Using P2A bridge for configuration
> > > [   46.140737] ast 0000:03:00.0: [drm] AST 2500 detected
> > > [   46.140754] ast 0000:03:00.0: [drm] Analog VGA only
> > > [   46.140772] ast 0000:03:00.0: [drm] dram MCLK=800 Mhz type=7
> > > bus_width=16
> > > [   46.153553] [drm] Initialized ast 0.1.0 20120228 for 0000:03:00.0
> > > on minor 0
> > > [   46.165097] fbcon: astdrmfb (fb0) is primary device
> > > [   46.391381] ast 0000:03:00.0: [drm] fb0: astdrmfb frame buffer device
> > > [   56.097697] systemd[1]: Starting Load Kernel Module drm...
> > > [   56.343556] systemd[1]: modprobe at drm.service: Succeeded.
> > > [   56.350382] systemd[1]: Finished Load Kernel Module drm.
> > > [13319.469462] [   2683] 70889  2683    55586        0    73728
> > > 138             0 tdrm
> > > [13320.658386] [   2683] 70889  2683    55586        0    73728
> > > 138             0 tdrm
> > > [13321.800970] [   2683] 70889  2683    55586        0    73728
> > > 138             0 tdrm
> > 
> > _______________________________________________
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> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> 
> -- 
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Maxfeldstr. 5, 90409 Nürnberg, Germany
> (HRB 36809, AG Nürnberg)
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>