34c6cf2f40
To check system memory state lmkd is using same files every time vmpressure event is received. Instead of opening and closing these files every time we store the file descriptor and use pread() to reread the file from the beginning. Bug: 77299493 Bug: 75322373 Change-Id: I8e27f8b9526e82e3cc313a02fce215c2e4dd3d29 Signed-off-by: Suren Baghdasaryan <surenb@google.com> |
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| include | ||
| tests | ||
| Android.bp | ||
| OWNERS | ||
| README.md | ||
| liblmkd_utils.c | ||
| lmkd.c | ||
| lmkd.rc | ||
| statslog.c | ||
| statslog.h | ||
README.md
Android Low Memory Killer Daemon
Introduction
Android Low Memory Killer Daemon (lmkd) is a process monitoring memory state of a running Android system and reacting to high memory pressure by killing the least essential process(es) to keep system performing at acceptable levels.
Background
Historically on Android systems memory monitoring and killing of non-essential processes was handled by a kernel lowmemorykiller driver. Since Linux Kernel 4.12 the lowmemorykiller driver has been removed and instead userspace lmkd daemon performs these tasks.
Android Properties
lmkd can be configured on a particular system using the following Android properties:
ro.config.low_ram: choose between low-memory vs high-performance device. Default = false.
ro.lmk.low: min oom_adj score for processes eligible to be killed at low vmpressure level. Default = 1001 (disabled)
ro.lmk.medium: min oom_adj score for processes eligible to be killed at medium vmpressure level. Default = 800 (non-essential processes)
ro.lmk.critical: min oom_adj score for processes eligible to be killed at critical vmpressure level. Default = 0 (all processes)
ro.lmk.critical_upgrade: enables upgrade to critical level. Default = false
ro.lmk.upgrade_pressure: max mem_pressure at which level will be upgraded because system is swapping too much. Default = 100 (disabled)
ro.lmk.downgrade_pressure: min mem_pressure at which vmpressure event will be ignored because enough free memory is still available. Default = 100 (disabled)
ro.lmk.kill_heaviest_task: kill heaviest eligible task (best decision) vs. any eligible task (fast decision). Default = false
ro.lmk.kill_timeout_ms: duration in ms after a kill when no additional kill will be done, Default = 0 (disabled)
ro.lmk.debug: enable lmkd debug logs, Default = false