> Since your 1MB malloc'ed buffers may not fall on page boundaries, > and there might occasionally be other malloc'ed areas interspersed > amongst them, I'm not surprised that pages_sharing falls a little > short of 98302. But I am surprised that pages_unshared does not > make up the difference; probably pages_volatile does, but I don't > see why some should remain volatile indefinitely. The test program (http://people.redhat.com/qcai/ksm01.c) was changed to use mmap instead of malloc, and pages_sharing was short of the expected value and pages_volatile was indeed non-zero. Those makes it is difficult to predict pages_sharing and pages_volatile although it might be fine to check pages_sharing + pages_volatile with an expected value. Any suggestion to alter the test code to check the stable numbers? Thanks. ksm01 0 TINFO : child 0 allocates 128 MB filled with 'c'. ksm01 0 TINFO : child 1 allocates 128 MB filled with 'a'. ksm01 0 TINFO : child 2 allocates 128 MB filled with 'a'. ksm01 0 TINFO : pages_shared is 2. ksm01 0 TINFO : pages_sharing is 98300. ksm01 0 TINFO : pages_unshared is 0. ksm01 0 TINFO : pages_volatile is 2. ksm01 0 TINFO : child 1 changes memory content to 'b'. ksm01 0 TINFO : pages_shared is 3. ksm01 0 TINFO : pages_sharing is 98291. ksm01 0 TINFO : pages_unshared is 0. ksm01 0 TINFO : pages_volatile is 10. ksm01 0 TINFO : child 0 changes memory content to 'd'. ksm01 0 TINFO : child 1 changes memory content to 'd' ksm01 0 TINFO : child 2 changes memory content to 'd' ksm01 0 TINFO : pages_shared is 1. ksm01 0 TINFO : pages_sharing is 98299. ksm01 0 TINFO : pages_unshared is 0. ksm01 0 TINFO : pages_volatile is 4. ksm01 0 TINFO : child 1 changes one page to 'e'. ksm01 0 TINFO : pages_shared is 1. ksm01 0 TINFO : pages_sharing is 98299. ksm01 0 TINFO : pages_unshared is 1. ksm01 0 TINFO : pages_volatile is 3. CAI Qian -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>