Hi, Michael. On Monday, 09 August 2010 19:28:23 +0400, Michael Tokarev wrote: >> I'm also using qemu-kvm 0.12.1.2 compiled by myself with the source >> code of SourceForge. > Note that this one has numerous bugs, some of which involves data > corruption. JFYI. Thanks for the observation. >> These are the checks that I was doing in the VMHost: >> >> # ll /sys/kernel/mm/ksm/ >> total 0 >> -r--r--r-- 1 root root 4096 ago 9 06:28 full_scans >> -rw-r--r-- 1 root root 4096 ago 9 06:28 max_kernel_pages >> -r--r--r-- 1 root root 4096 ago 9 06:28 pages_shared >> -r--r--r-- 1 root root 4096 ago 9 06:28 pages_sharing >> -rw-r--r-- 1 root root 4096 ago 9 06:28 pages_to_scan >> -r--r--r-- 1 root root 4096 ago 9 06:28 pages_unshared >> -r--r--r-- 1 root root 4096 ago 9 06:28 pages_volatile >> -rw-r--r-- 1 root root 4096 ago 9 06:27 run >> -rw-r--r-- 1 root root 4096 ago 9 06:28 sleep_millisecs >> >> >> # cat /sys/kernel/mm/ksm/max_kernel_pages >> 253500 >> >> But KSM seems not work: >> >> # cat /sys/kernel/mm/ksm/pages_sharing >> 0 > Did you actually enable it in the kernel? Did you read the ksm docs > shipped with the kernel? Yes, I forgot to mention that I had enabled it: # cat /sys/kernel/mm/ksm/run 1 >> Should I have some additional consideration when compiling qemu-kvm? > Please note what Nikola Ciprich said. If you don't have kernel headers > that defines MADV_MERGEABLE, you'll have to define it when compiling > kvm. > Note again that debian qemu-kvm package (you're asking about debian > after all) includes support for KSM. It also includes a small patch to > #define that symbol. Keeping the kernel I had compiled and installing the qemu-kvm package in Backports, now KSM is working: # cat /sys/kernel/mm/ksm/pages_sharing 181406 This indicates that this was a problem in compiling qemu-kvm since the kernel is still exactly the same. Now, according to what I was seeing, headers of my kernel defines MADV_MERGEABLE: # cat /usr/src/linux-2.6.32.3/debian/linux-headers-2.6.32.3-dgb/usr/src/linux-headers-2.6.32.3-dgb/include/asm-generic/mman-common.h | grep MERGEABLE #define MADV_MERGEABLE 12 /* KSM may merge identical pages */ #define MADV_UNMERGEABLE 13 /* KSM may not merge identical pages */ Would it be that perhaps in my compilation of qemu-kvm, ksm was not working because I would have to indicate the path /usr/src/linux-2.6.32.3/debian/...? Thanks for your reply. Regards, Daniel -- Fingerprint: BFB3 08D6 B4D1 31B2 72B9 29CE 6696 BF1B 14E6 1D37 Powered by Debian GNU/Linux Lenny - Linux user #188.598
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