proc_sys_vm(5) File Formats Manual proc_sys_vm(5) (NAME) /proc/sys/vm/ - (DESCRIPTION) /proc/sys/vm/ () . /proc/sys/vm/admin_reserve_kbytes ( 3.10) ( KiB) CAP_SYS_ADMIN . [ ] KiB . (superuser) (kill ) overcommit ( 0 /proc/sys/vm/overcommit_memory). <>> ( 2 /proc/sys/vm/overcommit_memory) ( login(1) ssh(1) top(1)). . x86-64 131072 ( ) . . /proc/sys/vm/compact_memory ( 2.6.35) 1 (zone) . /proc/buddyinfo . CONFIG_COMPACTION . /proc/sys/vm/drop_caches ( 2.6.16) (clean caches) (dentries) (inodes) . . () . pagecache : echo 1 > /proc/sys/vm/drop_caches dentries inodes : echo 2 > /proc/sys/vm/drop_caches pagecache dentries inodes : echo 3 > /proc/sys/vm/drop_caches (dirty objects) sync(1) . /proc/sys/vm/hugetlb_shm_group ( 2.6.7) (GID) (huge pages) . CAP_IPC_LOCK huge-page : memfd_create(2) mmap(2) shmget(2). /proc/sys/vm/legacy_va_layout ( 2.6.9) (2.4) . /proc/sys/vm/memory_failure_early_kill ( 2.6.32) ( ) . ( ) . . : 1 . swap cache . 0 (unmap) . kill SIGBUS si_code BUS_MCEERR_AO . sigaction(2) . / (machine check handling) . memory_failure_early_kill PR_MCE_KILL prctl(2) . CONFIG_MEMORY_FAILURE . /proc/sys/vm/memory_failure_recovery ( 2.6.32) ( ). 1 . 0 (panic) . CONFIG_MEMORY_FAILURE . /proc/sys/vm/oom_dump_tasks ( 2.6.25) ( ) OOM-killing . ( ) : ( ) (resident set size) (CPU) oom_adj ( /proc/pid/oom_adj ) . OOM-killer . . . OOM . OOM- killer . 0 . /proc/sys/vm/oom_kill_allocating_task ( 2.6.24) (out-of-memory) OOM . OOM-killer (tasklist) . . OOM-killer . . /proc/sys/vm/panic_on_oom /proc/sys/vm/oom_kill_allocating_task . 0 . /proc/sys/vm/overcommit_kbytes ( 3.14) /proc/sys/vm/overcommit_ratio CommitLimit /proc/sys/vm/overcommit_memory 2 . overcommitting ( kB) overcommit_ratio . CommitLimit . overcommit_kbytes overcommit_ratio : overcommit_kbytes CommitLimit overcommit_ratio . . /proc/sys/vm/overcommit_memory . : 0: (heuristic overcommit - ) 1: overcommit 2: overcommit 0 mmap(2) MAP_NORESERVE OOM-killer . 1 . (large sparse arrays) . 2.6.0 1 . 2 ( 2.6) (CommitLimit /proc/meminfo) : CommitLimit = (total_RAM - total_huge_TLB) * overcommit_ratio / 100 + total_swap : o total_RAM RAM o total_huge_TLB (huge pages) o overcommit_ratio /proc/sys/vm/overcommit_ratio o total_swap (swap) . RAM swap overcommit_ratio CommitLimit . 3.14 /proc/sys/vm/overcommit_kbytes CommitLimit : CommitLimit = overcommit_kbytes + total_swap /proc/sys/vm/admin_reserve_kbytes /proc/sys/vm/user_reserve_kbytes . /proc/sys/vm/overcommit_ratio ( 2.6.0) (overcommitted ). 50 . /proc/sys/vm/overcommit_memory . /proc/sys/vm/panic_on_oom ( 2.6.18) (panic) (out-of-memory) . 0 OOM-killer . OOM-killer . 1 panic . (mbind(2) MPOL_BIND) cpusets (cpuset(7)) OOM-killer . : . 2 (panic) . 0 . 1 2 (failover) . failover . /proc/sys/vm/swappiness (swap) . . 60 . /proc/sys/vm/user_reserve_kbytes ( 3.10) ( KiB) . ( ). /proc/sys/vm/overcommit_memory 2 ( <>>) . [ user_reserve_kbytes] . [ 128MiB] KiB . ( /proc/sys/vm/admin_reserve_kbytes ). "fork: Cannot allocate memory" . . /proc/sys/vm/unprivileged_userfaultfd ( 5.2) ( ) (unprivileged) userfaultfd(2) . 1 userfaultfd(2) . 0 CAP_SYS_PTRACE userfaultfd(2) . 1 . (SEE ALSO) proc(5), proc_sys(5) Linux man-pages 6.19 2026-02-08 proc_sys_vm(5)