> On Tue 19-11-24 20:29:22, Jim Zhao wrote: > > Thanks, Jan, I just sent patch v2, could you please review it ? > > Yes, the patch looks good to me. > > > > > And I found the debug info in the bdi stats. > > The BdiDirtyThresh value may be greater than DirtyThresh, and after > > applying this patch, the value of BdiDirtyThresh could become even > > larger. > > > > without patch: > > --- > > root@ubuntu:/sys/kernel/debug/bdi/8:0# cat stats > > BdiWriteback: 0 kB > > BdiReclaimable: 96 kB > > BdiDirtyThresh: 1346824 kB > > But this is odd. The machine appears to have around 3GB of memory, doesn't > it? I suspect this is caused by multiple cgroup-writeback contexts > contributing to BdiDirtyThresh - in fact I think the math in > bdi_collect_stats() is wrong as it is adding wb_thresh() calculated based > on global dirty_thresh for each cgwb whereas it should be adding > wb_thresh() calculated based on per-memcg dirty_thresh... You can have a > look at /sys/kernel/debug/bdi/8:0/wb_stats file which should have correct > limits as far as I'm reading the code. Thanks for review! Yes, It should be caused by multiple cgroup-writeback with bdi_collect_stats issue. @Andrew, I sent patch v2 according Jan's suggestion. Since patch v1 already in tree. So I sent out the diff of v1 -> v2: https://lore.kernel.org/all/20241121100539.605818-1-jimzhao.ai@xxxxxxxxx/ Could you please review it, thanks! Jim Zhao
