Hi all,
This is the third RFC. As suggested by Minchan Kim, the API is much simplified now (comparing to vmevent_fd):
- As well as Minchan, KOSAKI Motohiro didn't like the timers, so the timers are gone now; - Pekka Enberg didn't like the complex attributes matching code, and so it is no longer there; - Nobody liked the raw vmstat attributes, and so they were eliminated too.
But, conceptually, it is the exactly the same approach as in v2: three discrete levels of the pressure -- low, medium and oom. The levels are based on the reclaimer inefficiency index as proposed by Mel Gorman, but userland does not see the raw index values. The description why I moved away from reporting the raw 'reclaimer inefficiency index' can be found in v2: http://lkml.org/lkml/2012/10/22/177
While the new API is very simple, it is still extensible (i.e. versioned).
As there are a lot of drastic changes in the API itself, I decided to just add a new files along with vmevent, it is much easier to review it this way (I can prepare a separate patch that removes vmevent files, if we care to preserve the history through the vmevent tree).
Thanks, Anton.
-- Documentation/sysctl/vm.txt | 47 +++++ arch/x86/syscalls/syscall_64.tbl | 1 + include/linux/syscalls.h | 2 + include/linux/vmpressure.h | 128 ++++++++++++ kernel/sys_ni.c | 1 + kernel/sysctl.c | 31 +++ mm/Kconfig | 13 ++ mm/Makefile | 1 + mm/vmpressure.c | 231 +++++++++++++++++++++ mm/vmscan.c | 5 + tools/testing/vmpressure/.gitignore | 1 + tools/testing/vmpressure/Makefile | 30 +++ tools/testing/vmpressure/vmpressure-test.c | 93 +++++++++ 13 files changed, 584 insertions(+)