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? -- Kirill A. Shutemov
