On Thu, Jun 27, 2019 at 09:06:01PM +0300, Kirill A. Shutemov wrote: > On Thu, Jun 27, 2019 at 08:54:00PM +0900, Minchan Kim wrote: > > - Problem > > > > Naturally, cached apps were dominant consumers of memory on the system. > > However, they were not significant consumers of swap even though they are > > good candidate for swap. Under investigation, swapping out only begins > > once the low zone watermark is hit and kswapd wakes up, but the overall > > allocation rate in the system might trip lmkd thresholds and cause a cached > > process to be killed(we measured performance swapping out vs. zapping the > > memory by killing a process. Unsurprisingly, zapping is 10x times faster > > even though we use zram which is much faster than real storage) so kill > > from lmkd will often satisfy the high zone watermark, resulting in very > > few pages actually being moved to swap. > > Maybe we should look if we do The Right Thing™ at system-wide level before > introducing new API? How changing swappiness affects your workloads? What > is swappiness value in your setup? It was 100. Even, I tried 150 and 200 with simple hack of swappiness. However, it caused too excessive swpout. Anyway, systen-level tune is generally good but if process has hint, that should work better and that's why advise API is.
