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. > > +Minchan, Sergey, > > Do you think we can implement this change in zRAM by using PAGE_SIZE instead > > of 2 * PAGE_SIZE? > > Sorry again, what problem are you solving? For compression, there is no point in allocating a destination buffer that is bigger than the original. Cheers, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
