On (25/02/23 08:24), Herbert Xu wrote: > On Sat, Feb 22, 2025 at 09:31:41PM +0900, Sergey Senozhatsky wrote: > > > > The idea behind zram's code is that incompressible pages are not unusual, > > they are quite usual, in fact, It's not necessarily that the data grew > > in size after compression, the data is incompressible from zsmalloc PoV. > > That is the algorithm wasn't able to compress a PAGE_SIZE buffer to an > > object smaller than zsmalloc's huge-class-watermark (around 3600 bytes, > > depending on zspage chain size). That's why we look at the comp-len. > > Anything else is an error, perhaps a pretty catastrophic error. > > If you're rejecting everything above the watermark then you should > simply pass the watermark as the output length to the algorithm so > that it can stop doing useless work once it gets past that point. Makes sense.
