On 3/16/21 1:30 PM, Yu Zhao wrote: > On Tue, Mar 16, 2021 at 07:50:23AM -0700, Dave Hansen wrote: >> I think it would also be very worthwhile to include some research in >> this series about why the kernel moved away from page table scanning. >> What has changed? Are the workloads we were concerned about way back >> then not around any more? Has faster I/O or larger memory sizes with a >> stagnating page size changed something? > > Sure. Hugh also suggested this too but I personally found that ancient > pre-2.4 history too irrelevant (and uninteresting) to the modern age > and decided to spare audience of the boredom. IIRC, rmap chains showed up in the 2.5 era and the VM was quite bumpy until anon_vmas came around, which was early-ish in the 2.6 era. But, either way, I think there is a sufficient population of nostalgic crusty old folks around to warrant a bit of a history lesson. We'll enjoy the trip down memory lane, fondly remembering the old days in Ottawa... >>> nr_vmscan_write 24900719 >>> nr_vmscan_immediate_reclaim 115535 >>> pgscan_kswapd 320831544 >>> pgscan_direct 23396383 >>> pgscan_direct_throttle 0 >>> pgscan_anon 127491077 >>> pgscan_file 216736850 >>> slabs_scanned 400469680 >>> compact_migrate_scanned 1092813949 >>> compact_free_scanned 4919523035 >>> compact_daemon_migrate_scanned 2372223 >>> compact_daemon_free_scanned 20989310 >>> unevictable_pgs_scanned 307388545 > > 10G swap + 8G anon rss + 6G file rss, hmm... an interesting workload. > The file rss does seem a bit high to me, my wild speculation is there > have been git/make activities in addition to a VM? I wish I was doing more git/make activities. It's been an annoying amount of email and web browsers for 12 days. If anything, I'd suspect that Thunderbird is at fault for keeping a bunch of mail in the page cache. There are a couple of VM's running though.
