On 2016/3/3 9:56, Jerry Lee wrote: > Hi, > > Thanks for sharing the same experience and workaround with me. > But it's kind of hard for me to set all the possible processes to no-kswapd flag > in advance so that they would not trigger kswapd in the future. > > Cheers, > - Jerry > > On 2 March 2016 at 22:21, chen feng <puck.chen@xxxxxxxxxxx <mailto:puck.chen@xxxxxxxxxxx>> wrote: > > > > On 2016/3/2 14:20, Jerry Lee wrote: > > Hi, > > > > I have a x86_64 system with 2G RAM using linux-3.12.x. During copying > > large > > files (e.g. 100GB), kswapd easily consumes 100% CPU until the file is > > deleted > > or the page cache is dropped. With setting the min_free_kbytes from 16384 > > to > > 65536, the symptom is mitigated but I can't totally get rid of the problem. > > > > After some trial and error, I found that highest zone is always unbalanced > > with > > order-0 page request so that pgdat_blanaced() continuously return false and > > kswapd can't sleep. > > > > Here's the watermarks (min_free_kbytes = 65536) in my system: > > Node 0, zone DMA > > pages free 2167 > > min 138 > > low 172 > > high 207 > > scanned 0 > > spanned 4095 > > present 3996 > > managed 3974 > > > > Node 0, zone DMA32 > > pages free 215375 > > min 16226 > > low 20282 > > high 24339 > > scanned 0 > > spanned 1044480 > > present 490971 > > managed 464223 > > > > Node 0, zone Normal > > pages free 7 > > min 18 > > low 22 > > high 27 > > scanned 0 > > spanned 1536 > > present 1536 > > managed 523 > > > > Besides, when the kswapd crazily spins, the value of the following entries > > in vmstat increases quickly even when I stop copying file: > > > > pgalloc_dma 17719 > > pgalloc_dma32 3262823 > > slabs_scanned 937728 > > kswapd_high_wmark_hit_quickly 54333233 > > pageoutrun 54333235 > > > > Is there anything I could do to totally get rid of the problem? > > \ > Yes, I have the same issue on arm64 platform. > > I think you can increase the normal ZONE size. And I think there will be a memory alloc process > in your system which tigger the kswapd too frequently. > > You can set this process to no-kswapd flag will also solve this issue. > > Thanks > > Just hack the process who tigger it too frequenctly. > > -- 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>