Messages in this thread | | | Date | Tue, 09 Apr 2013 18:05:30 +0800 | From | Simon Jeons <> | Subject | Re: [PATCH] mm: page_alloc: Avoid marking zones full prematurely after zone_reclaim() |
| |
Hi Michal, On 04/05/2013 02:31 PM, Simon Jeons wrote: > Hi Michal, > On 03/21/2013 04:19 PM, Michal Hocko wrote: >> On Thu 21-03-13 10:33:07, Simon Jeons wrote: >>> Hi Mel, >>> On 03/21/2013 02:19 AM, Mel Gorman wrote: >>>> The following problem was reported against a distribution kernel when >>>> zone_reclaim was enabled but the same problem applies to the mainline >>>> kernel. The reproduction case was as follows >>>> >>>> 1. Run numactl -m +0 dd if=largefile of=/dev/null >>>> This allocates a large number of clean pages in node 0 >>> I confuse why this need allocate a large number of clean pages? >> It reads from file and puts pages into the page cache. The pages are not >> modified so they are clean. Output file is /dev/null so no pages are >> written. dd doesn't call fadvise(POSIX_FADV_DONTNEED) on the input file >> by default so pages from the file stay in the page cache > > I try this in v3.9-rc5: > dd if=/dev/sda of=/dev/null bs=1MB > 14813+0 records in > 14812+0 records out > 14812000000 bytes (15 GB) copied, 105.988 s, 140 MB/s > > free -m -s 1 > > total used free shared buffers > cached > Mem: 7912 1181 6731 0 663 239 > -/+ buffers/cache: 277 7634 > Swap: 8011 0 8011 > > It seems that almost 15GB copied before I stop dd, but the used pages > which I monitor during dd always around 1200MB. Weird, why? >
Sorry for waste your time, but the test result is weird, is it?
| |