Re: [Crash-utility] [RFC PATCH v3 0/2] Show memory overcommit data in dump_kmeminfo()

The first patch changes dump_kmeminfo() to report overcommit information similar to that displayed under the proc/meminfo file. It may be useful to indicate memory over commitment abuse, for example with forced vmcores from system hangs due to shortage of memory. The intended output is as follows: crash> kmem -i PAGES TOTAL PERCENTAGE TOTAL MEM 1965332 7.5 GB ---- FREE 78080 305 MB 3% of TOTAL MEM USED 1887252 7.2 GB 96% of TOTAL MEM SHARED 789954 3 GB 40% of TOTAL MEM BUFFERS 110606 432.1 MB 5% of TOTAL MEM CACHED 1212645 4.6 GB 61% of TOTAL MEM SLAB 146563 572.5 MB 7% of TOTAL MEM TOTAL SWAP 1970175 7.5 GB ---- SWAP USED 5 20 KB 0% of TOTAL SWAP SWAP FREE 1970170 7.5 GB 99% of TOTAL SWAP COMMIT LIMIT 2952841 11.3 GB ---- COMMITTED 1150595 4.4 GB 38% of TOTAL LIMIT The second patch simply removes the mention of dump_zone_page_usage() availability from kmem's help page. Tested under 3.16.4-200.fc20.x86_64 only. Though this should work under RHEL4 (2.6.9-5) and above whereby the kernel symbol sysctl_overcommit_memory is available. Changelog: v2 -> v3: - Appropriately avoid a divide-by-zero when the "allowed" variable is correctly set to 0 (e.g. overcommit_ratio is 0 and swap device is off) - Initialised the following members of offset_table in vm_init(): hstate_order, hstate_nr_huge_pages, hstate_free_huge_pages and hstate_name - percpu_counter_struct_count and atomic_t_counter have been added to offset_table and each initialised in kernel_init()