Hi Minchan, On Thu, Aug 15, 2013 at 01:17:53AM +0900, Minchan Kim wrote: >Hi Luigi, > >On Wed, Aug 14, 2013 at 08:53:31AM -0700, Luigi Semenzato wrote: >> During earlier discussions of zswap there was a plan to make it work >> with zsmalloc as an option instead of zbud. Does zbud work for > >AFAIR, it was not an optoin but zsmalloc was must but there were >several objections because zswap's notable feature is to dump >compressed object to real swap storage. For that, zswap needs to >store bounded objects in a zpage so that dumping could be bounded, too. >Otherwise, it could encounter OOM easily. > >> compression factors better than 2:1? I have the impression (maybe >> wrong) that it does not. In our use of zram (Chrome OS) typical > >Since zswap changed allocator from zsmalloc to zbud, I didn't follow >because I had no interest of low compressoin ratio allocator so >I have no idea of status of zswap at a moment but I guess it would be >still 2:1. > >> overall compression ratios are between 2.5:1 and 3:1. We would hate >> to waste that memory if we switch to zswap. > >If you have real swap storage, zswap might be better although I have >no number but real swap is money for embedded system and it has sudden >garbage collection on firmware side if we use eMMC or SSD so that it >could affect system latency. Morever, if we start to use real swap, >maybe we should encrypt the data and it would be severe overhead(CPU >and Power). > Why real swap for embedded system need encrypt the data? I think there is no encrypt for data against server and desktop. >And what I am considering after promoting for zram feature is >asynchronous I/O and it's possible because zram is block device. > >Thanks! >-- >Kind regards, >Minchan Kim > >-- >To unsubscribe, send a message with 'unsubscribe linux-mm' in >the body to majordomo@xxxxxxxxx. For more info on Linux MM, >see: http://www.linux-mm.org/ . >Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>