On 03/25/20 at 12:45pm, David Rientjes wrote: > On Wed, 25 Mar 2020, Baoquan He wrote: > > > > Even this can break existing parsers. Fixing that up is likely not hard > > > and existing parsers would be mostly debugging hacks here and there but > > > I do miss any actual justification except for you considering it more > > > sensible. I do not remember this would be a common pain point for people > > > parsing this file. If anything the overal structure of the file makes it > > > hard to parse and your patches do not really address that. We are likely > > > too late to make the output much more sensible TBH. > > > > > > That being said, I haven't looked more closely on your patches because I > > > do not have spare cycles for that. Your justification for touching the > > > code which seems to be working relatively well is quite weak IMHO, yet > > > it adds a non zero risk for breaking existing parsers. > > > > I would take the saying of non zero risk for breaking existing parsers. > > When considering this change, I thought about the possible risk. However, > > found out the per-node stats was added in 2016 which is not so late, and > > assume nobody will rely on the order of per-node stats embeded into a > > zone. But I have to admit any concern or worry of risk is worth being > > considerred carefully since /proc/zoneinfo is a classic interface. > > > > For context, we started parsing /proc/zoneinfo in initscripts to be able > to determine the order in which vm.lowmem_reserve_ratio needs to be set > and this required my kernel change from 2017: > > commit b2bd8598195f1b2a72130592125ac6b4218988a2 > Author: David Rientjes <rientjes@xxxxxxxxxx> > Date: Wed May 3 14:52:59 2017 -0700 > > mm, vmstat: print non-populated zones in zoneinfo > > Otherwise, we found, it's much more difficult to determine how this array > should be structured. So at least we parse this file very carefully, I'm > not sure how much others do, but it seems like an unnecessary risk for > little reward. I'm happy to see it has been decided to drop this patch > and patch 5. OK, I see why it is in such a situation, the empty zones were not printed. I could still not get how vm.lowmem_reserve_ratio is set with /proc/zoneinfo in the old initscripts, do you see any risk if not filling and showing the ->lowmem_reserve[] of empty zone in patch 2 and 3? Thanks in advance.
