Messages in this thread | | | From | Pintu Kumar <> | Date | Mon, 17 Sep 2018 17:25:27 +0530 | Subject | Re: KSM not working in 4.9 Kernel |
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On Mon, Sep 17, 2018 at 11:46 AM Pintu Kumar <pintu.ping@gmail.com> wrote: > > > But still no effect. > > > And I checked LTP test cases. It almost doing the same thing. > > > > > > I observed that [ksmd] thread is not waking up at all. > > > I gave some print inside it, but I could never saw that prints coming. > > > I could not find it running either in top command during the operation. > > > Is there anything needs to be done, to wakw up ksmd? > > > I already set: echo 1 > /sys/kernel/mm/ksm. > > > > It should be echo 1 > /sys/kernel/mm/ksm/run > > > > Oh yes, sorry for the typo. > I tried the same, but still ksm is not getting invoked. > Could someone confirm if KSM was working in 4.9 kernel? >
Ok, it's working now. I have to explicitly stop the ksm thread to see the statistics. Also there was some internal patch that was setting vm_flags to VM_MERGABLE thus causing ksm_advise call to return.
# echo 1 > /sys/kernel/mm/ksm/run # ./malloc-test.out & # echo 0 > /sys/kernel/mm/ksm/run
~ # grep -H '' /sys/kernel/mm/ksm/* /sys/kernel/mm/ksm/full_scans:105 /sys/kernel/mm/ksm/pages_shared:1 /sys/kernel/mm/ksm/pages_sharing:999 /sys/kernel/mm/ksm/pages_to_scan:100 /sys/kernel/mm/ksm/pages_unshared:0 /sys/kernel/mm/ksm/pages_volatile:0 /sys/kernel/mm/ksm/run:0 /sys/kernel/mm/ksm/sleep_millisecs:20
However, I have one doubt. Is the above data correct, for the below program?
int main(int argc, char *argv[]) { int i, n, size, ret; char *buffer; void *addr;
n = 10; size = 100 * getpagesize(); for (i = 0; i < n; i++) { buffer = (char *)malloc(size); memset(buffer, 0xff, size); madvise(buffer, size, MADV_MERGEABLE); addr = mmap(NULL, size, PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); memset(addr, 0xff, size); ret = madvise(addr, size, MADV_MERGEABLE); if (ret < 0) { fprintf(stderr, "madvise failed: ret: %d, reason: %s\n", ret, strerror(errno)); } usleep(500); } printf("Done....press ^C\n");
pause();
return 0; }
Thanks, Pintu
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