Messages in this thread | | | Date | Mon, 25 Jan 2016 15:54:26 +0100 | From | Andrea Arcangeli <> | Subject | Re: [lkp] [ksm] 40e318e509: ltp.ksm01.fail |
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Hello,
On Mon, Jan 25, 2016 at 11:04:18AM +0800, kernel test robot wrote: > FYI, we noticed the below changes on > > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > commit 40e318e509d2c9f3cdb00ef32d2c14b9868af16b ("ksm: introduce ksm_max_page_sharing per page deduplication limit") > > We found LKP KSM test case failed for your patch. > > ========================================================================================= > compiler/kconfig/rootfs/tbox_group/test/testcase: > gcc-5/x86_64-nfsroot/debian-x86_64-2015-02-07.cgz/vm-lkp-wsx03-4G/mm_functional_positive/otc_kernel_qa-ts_ltp_ddt > > commit: > 77505a33e539477f1fbe5e6136df5b265f39cccf > 40e318e509d2c9f3cdb00ef32d2c14b9868af16b > > 77505a33e539477f 40e318e509d2c9f3cdb00ef32d > ---------------- -------------------------- > fail:runs %reproduction fail:runs > | | | > :4 100% 4:4 otc_kernel_qa-ts_ltp_ddt.ksm01.fail > :4 100% 4:4 otc_kernel_qa-ts_ltp_ddt.ksm01_1.fail
In this case it's one rare case of false positive. The change in the merging levels is a "feature" not a "bug".
LTP validation math on ksm sysfs levels shall be updated to account for the runtime value of /sys/kernel/mm/ksm/max_page_sharing which in turn affects pages_sharing/pages_shared. In fact you could add validation for the new fields like stable_node_dups and stable_node_chains on top of the existing verifications on pages_shar*.
For now you should re-run the test after:
echo 2 >/sys/kernel/mm/ksm/run echo 10000000 > /sys/kernel/mm/ksm/max_page_sharing echo 1 >/sys/kernel/mm/ksm/run
And then LTP will pass as usual.
Thanks for the greatly valuable regression testing work, Andrea
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