Hi Sergey and Rui, On Thu, Oct 29, 2020 at 03:59:27AM +0900, Sergey Senozhatsky wrote: > Cc-ing Andrew > > message-id: 20201028115921.848-1-rsalvaterra@xxxxxxxxx > > On (20/10/28 11:59), Rui Salvaterra wrote: > > There's nothing special about zram and lzo. It works just fine without it, so > > as long as at least one of the other supported compression algorithms is > > selected. > > > > Suggested-by: Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx> > > Signed-off-by: Rui Salvaterra <rsalvaterra@xxxxxxxxx> Sorry for the late. I am still looking for the time to look into this patch. I totally agree with the motivation of Rui. Before that, just a dumb question. Can't we just provide choice/endchoice in Kconfig to select default comp algorithm from admin? > > Minchan, I'm fine with the change. > > Two things from my side: > > 1) The commit message, probably, can be a bit more informative. Something > like this? > > ZRAM always enables CRYPTO_LZO because lzo-rle is the hardcoded > fallback compression algorithm, which means that on systems where > ZRAM always use, for instance, CRYPTO_ZSTD lzo kernel module > becomes unneeded. This patch removes the hardcoded lzo-lre > dependency, instead ZRAM picks the first supported CRYPTO > compression algorithm, should it be ZSTD or LZ4, etc; and only > forcibly enables CRYPTO_LZO (previous behaviour) if none of the > alternative algorithms were selected. > > > 2) The ZRAM_AUTOSEL_ALGO allows to deselect CRYPTO_LZO only if > CRYPTO_LZ4/CRYPTO_LZ4HC/CRYPTO_842/CRYPTO_ZSTD are compiled in (=y). > If any of the algorithms is selected as a module (=m) then CRYPTO_LZO > is selected as the default algorithm. Apparently depends on !(CONFIG_FOO) > means depends on !(CONFIG_FOO=y). > > It appears that the below change fixes it, but it looks a bit ugly. > > --- > diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig > index 141ce0ebad06..f2fd34de9200 100644 > --- a/drivers/block/zram/Kconfig > +++ b/drivers/block/zram/Kconfig > @@ -15,7 +15,7 @@ config ZRAM > > config ZRAM_AUTOSEL_ALGO > def_bool y > - depends on ZRAM && !(CRYPTO_LZ4 || CRYPTO_LZ4HC || CRYPTO_842 || CRYPTO_ZSTD) > + depends on ZRAM && !(CRYPTO_LZ4=m || CRYPTO_LZ4HC=m || CRYPTO_842=m || CRYPTO_ZSTD=m || CRYPTO_LZ4=y || CRYPTO_LZ4HC=y || CRYPTO_842=y || CRYPTO_ZSTD=y) > select CRYPTO_LZO > > config ZRAM_WRITEBACK > --- > > -ss
