On 05/21/2012 04:51 PM, Christian Ehrhardt wrote: > [...] > >>> [missing patch #3] >>> I tried to get a similar patch working for swap out in >>> shrink_page_list. And >>> it worked in functional terms, but the additional mergin was negligible. >> >> >> I think we have already done it. >> Look at shrink_mem_cgroup_zone which ends up calling shrink_page_list >> so we already have applied >> I/O plugging. >> > > I saw that code and it is part of the kernel I used to test my patches. > But despite that code and my additional experiments of plug/unplug in > shrink_page_list the effective I/O size of swap write stays at almost 4k. I meant your plugging in shrink_page_list is redundant > > Thereby so far I can tell you that the plugs in shrink_page_list and > shrink_mem_cgroup_zone aren't sufficient - at least for my case. Yeb. > You saw the blocktrace summaries in my first mail, an excerpt of a write > submission stream looks like that: > > 94,4 10 465 0.023520923 116 A W 28868648 + 8 <- (94,5) > 28868456 > 94,5 10 466 0.023521173 116 Q W 28868648 + 8 [kswapd0] > 94,5 10 467 0.023522048 116 G W 28868648 + 8 [kswapd0] > 94,5 10 468 0.023522235 116 P N [kswapd0] > 94,5 10 469 0.023759892 116 I W 28868648 + 8 ( 237844) > [kswapd0] > 94,5 10 470 0.023760079 116 U N [kswapd0] 1 > 94,5 10 471 0.023760360 116 D W 28868648 + 8 ( 468) > [kswapd0] > 94,4 10 472 0.023891235 116 A W 28868656 + 8 <- (94,5) > 28868464 > 94,5 10 473 0.023891454 116 Q W 28868656 + 8 [kswapd0] > 94,5 10 474 0.023892110 116 G W 28868656 + 8 [kswapd0] > 94,5 10 475 0.023944610 116 I W 28868656 + 8 ( 52500) > [kswapd0] > 94,5 10 476 0.023944735 116 U N [kswapd0] 1 > 94,5 10 477 0.023944892 116 D W 28868656 + 8 ( 282) > [kswapd0] > 94,5 16 19 0.024023192 16033 C W 28868648 + 8 ( 262832) [0] > 94,5 24 37 0.024196752 14526 C W 28868656 + 8 ( 251860) [0] > [...] > > But we can split this discussion from my other two patches and I would > be happy to provide my test environment for further tests if there are > new suggestions/patches/... > >>> Maybe the cond_resched triggers much mor often than I expected, I'm >>> open for >>> suggestions regarding improving the pagout I/O sizes as well. >> >> >> We could enhance write out by batch like ext4_bio_write_page. >> > > Do you mean the changes brought by "bd2d0210 ext4: use bio layer instead > of buffer layer in mpage_da_submit_io" ? Yeb, I think it's helpful for your case but it's not trivial to implement it, IMHO. > > > -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>