Hi All, We've had a report[1] of an existing hugetlb setup that worked in Fedora 14 (2.6.35.x) and Fedora 15 (2.6.38-3.0?) that no longer works when using the 3.1.x kernel. The details in the bug are somewhat sparse on exactly which kernel version(s) worked and when it stopped working, but I thought I'd include some of the relevant comments to see if anyone can think of why this would stop working: 1. Allocate large pages through sysctl.conf, with the following: # Enable large page memory kernel.shmmax=25769803776 vm.nr_hugepages=10752 vm.hugetlb_shm_group=1001 There is 24 GB of memory on the server, and I'm allocating 21GB (I have done this on Fedora 14 and 15 with no issues. 2. Set /etc/security/limits.conf to allow for memlock to be unlimited for the user. 3. Create the hugetlb group, and put the users in that group. 4. Turn off transparent huge pages through a boot parameter transparent_hugepage=never 5. Run the following java command: java -XX:+UseLargePages -Xms8g -Xmx8g -version Actual results: java -XX:+UseLargePages -Xms8g -Xmx8g -version OpenJDK 64-Bit Server VM warning: Failed to reserve shared memory (errno = 28). java version "1.6.0_22" OpenJDK Runtime Environment (IcedTea6 1.10.4) (fedora-60.1.10.4.fc16-x86_64) Apparently dropping it to use 7G works though: java -XX:+UseLargePages -Xms7g -Xmx7g -version java version "1.6.0_22" OpenJDK Runtime Environment (IcedTea6 1.10.4) (fedora-60.1.10.4.fc16-x86_64) OpenJDK 64-Bit Server VM (build 20.0-b11, mixed mode) I'd appreciate any thoughts or further questions to ask for follow up. josh [1] https://bugzilla.redhat.com/show_bug.cgi?id=761262 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>