btw, I noticed that the same dd is constantly running from different CPUs. It's multi-core CPUs on the same socket, so should not be a big problem. I'll test NUMA setup later. This trace is for single dd case. dd-2893 [005] 3535.182111: balance_dirty_pages: bdi=8:0 dd-2893 [001] 3535.230125: balance_dirty_pages: bdi=8:0 dd-2893 [005] 3535.274805: balance_dirty_pages: bdi=8:0 dd-2893 [005] 3535.289337: balance_dirty_pages: bdi=8:0 dd-2893 [005] 3535.497863: balance_dirty_pages: bdi=8:0 dd-2893 [005] 3535.585510: balance_dirty_pages: bdi=8:0 dd-2893 [005] 3535.622001: balance_dirty_pages: bdi=8:0 dd-2893 [005] 3535.645003: balance_dirty_pages: bdi=8:0 dd-2893 [001] 3535.659603: balance_dirty_pages: bdi=8:0 dd-2893 [001] 3535.669497: balance_dirty_pages: bdi=8:0 dd-2893 [001] 3535.731294: balance_dirty_pages: bdi=8:0 dd-2893 [001] 3535.785879: balance_dirty_pages: bdi=8:0 dd-2893 [001] 3535.827724: balance_dirty_pages: bdi=8:0 dd-2893 [001] 3535.853108: balance_dirty_pages: bdi=8:0 dd-2893 [001] 3535.875667: balance_dirty_pages: bdi=8:0 dd-2893 [005] 3535.895731: balance_dirty_pages: bdi=8:0 dd-2893 [005] 3535.914920: balance_dirty_pages: bdi=8:0 dd-2893 [005] 3535.925765: balance_dirty_pages: bdi=8:0 dd-2893 [005] 3535.935545: balance_dirty_pages: bdi=8:0 dd-2893 [001] 3536.015888: balance_dirty_pages: bdi=8:0 dd-2893 [001] 3536.085571: balance_dirty_pages: bdi=8:0 Here is another run (1-dd): dd-3014 [001] 1248.388001: balance_dirty_pages: bdi=8:0 bdi_dirty=122640 avg_dirty=122643 dd-3014 [002] 1248.465999: balance_dirty_pages: bdi=8:0 bdi_dirty=122400 avg_dirty=122625 dd-3014 [007] 1248.531451: balance_dirty_pages: bdi=8:0 bdi_dirty=122240 avg_dirty=122600 dd-3014 [007] 1248.599260: balance_dirty_pages: bdi=8:0 bdi_dirty=122000 avg_dirty=122561 dd-3014 [003] 1248.667152: balance_dirty_pages: bdi=8:0 bdi_dirty=120840 avg_dirty=122447 dd-3014 [007] 1248.734848: balance_dirty_pages: bdi=8:0 bdi_dirty=120640 avg_dirty=122328 dd-3014 [007] 1248.798652: balance_dirty_pages: bdi=8:0 bdi_dirty=120440 avg_dirty=122210 dd-3014 [007] 1248.862456: balance_dirty_pages: bdi=8:0 bdi_dirty=120240 avg_dirty=122087 dd-3014 [003] 1248.926280: balance_dirty_pages: bdi=8:0 bdi_dirty=120040 avg_dirty=121960 dd-3014 [005] 1248.986091: balance_dirty_pages: bdi=8:0 bdi_dirty=119760 avg_dirty=121832 dd-3014 [005] 1249.045841: balance_dirty_pages: bdi=8:0 bdi_dirty=119600 avg_dirty=121702 And this 100 dd case looks much better (however it's not always the case): dd-2775 [007] 454.844907: balance_dirty_pages: bdi=8:0 bdi_dirty=104040 avg_dirty=409468930 dd-2775 [007] 455.048108: balance_dirty_pages: bdi=8:0 bdi_dirty=103800 avg_dirty=409676055 dd-2775 [007] 455.252347: balance_dirty_pages: bdi=8:0 bdi_dirty=103720 avg_dirty=409676055 dd-2775 [007] 455.455538: balance_dirty_pages: bdi=8:0 bdi_dirty=103800 avg_dirty=409676055 dd-2775 [007] 455.658597: balance_dirty_pages: bdi=8:0 bdi_dirty=103880 avg_dirty=409676055 dd-2775 [007] 455.862631: balance_dirty_pages: bdi=8:0 bdi_dirty=103760 avg_dirty=410276387 dd-2775 [007] 456.068149: balance_dirty_pages: bdi=8:0 bdi_dirty=103800 avg_dirty=410276387 dd-2775 [007] 456.266729: balance_dirty_pages: bdi=8:0 bdi_dirty=103760 avg_dirty=410833633 dd-2775 [007] 456.470184: balance_dirty_pages: bdi=8:0 bdi_dirty=103840 avg_dirty=410833633 dd-2775 [007] 456.668919: balance_dirty_pages: bdi=8:0 bdi_dirty=103960 avg_dirty=410833633 dd-2775 [007] 456.872522: balance_dirty_pages: bdi=8:0 bdi_dirty=103880 avg_dirty=411001977 dd-2775 [007] 457.070753: balance_dirty_pages: bdi=8:0 bdi_dirty=104040 avg_dirty=411001977 dd-2775 [007] 457.275970: balance_dirty_pages: bdi=8:0 bdi_dirty=103960 avg_dirty=411227747 dd-2775 [007] 457.473736: balance_dirty_pages: bdi=8:0 bdi_dirty=103920 avg_dirty=411534633 dd-2775 [007] 457.677204: balance_dirty_pages: bdi=8:0 bdi_dirty=103920 avg_dirty=412195106 dd-2775 [007] 457.881156: balance_dirty_pages: bdi=8:0 bdi_dirty=104040 avg_dirty=412195106 dd-2775 [007] 458.085173: balance_dirty_pages: bdi=8:0 bdi_dirty=103920 avg_dirty=412295260 dd-2775 [007] 458.285146: balance_dirty_pages: bdi=8:0 bdi_dirty=104000 avg_dirty=412295260 dd-2775 [007] 458.490109: balance_dirty_pages: bdi=8:0 bdi_dirty=103960 avg_dirty=412789184 dd-2775 [007] 458.692230: balance_dirty_pages: bdi=8:0 bdi_dirty=103960 avg_dirty=412789184 Thanks, Fengguang -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>