On Thu 14-07-16 19:36:59, Michal Hocko wrote: > On Thu 14-07-16 19:07:52, Ondrej Kozina wrote: > > On 07/14/2016 05:31 PM, Michal Hocko wrote: > > > On Thu 14-07-16 16:08:28, Ondrej Kozina wrote: > > > [...] > > > > As Mikulas pointed out, this doesn't work. The system froze as well with the > > > > patch above. Will try to tweak the patch with Mikulas's suggestion... > > > > > > Thank you for testing! Do you happen to have traces of the frozen > > > processes? Does the flusher still gets throttled because the bias it > > > gets is not sufficient. Or does it get throttled at a different place? > > > > > > > Sure. Here it is (including sysrq+t and sysrq+w output): https://okozina.fedorapeople.org/bugs/swap_on_dmcrypt/4.7.0-rc7+/1/4.7.0-rc7+.log > > Thanks a lot! This is helpful. > [ 162.716376] active_anon:107874 inactive_anon:108176 isolated_anon:64 > [ 162.716376] active_file:1086 inactive_file:1103 isolated_file:0 > [ 162.716376] unevictable:0 dirty:0 writeback:69824 unstable:0 > [ 162.716376] slab_reclaimable:3119 slab_unreclaimable:24124 > [ 162.716376] mapped:2165 shmem:57 pagetables:1509 bounce:0 > [ 162.716376] free:701 free_pcp:0 free_cma:0 > > No surprise that PF_LESS_THROTTLE didn't help. It gives some bias but > considering how many pages are under writeback it cannot possibly help > to prevent from sleeping in throttle_vm_writeout. I suppose adding > the following on top of the memalloc patch helps, right? > It is an alternative to what you were suggesting in other email but > it doesn't affect current_may_throttle paths which I would rather not > touch. Just read the other email and your patch properly and this is basically equivalent thing. I will think more about potential issues this might cause and send a proper patch for wider review. > --- > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index 7fbb2d008078..a37661f1a11b 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -1971,6 +1971,9 @@ void throttle_vm_writeout(gfp_t gfp_mask) > unsigned long background_thresh; > unsigned long dirty_thresh; > > + if (current->flags & PF_LESS_THROTTLE) > + return; > + > for ( ; ; ) { > global_dirty_limits(&background_thresh, &dirty_thresh); > dirty_thresh = hard_dirty_limit(&global_wb_domain, dirty_thresh); > -- > Michal Hocko > SUSE Labs -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>