From 875ae5661a011b757f0eaa468dea6ba91cbe5437 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Wed, 8 Jun 2016 19:36:09 +0200 Subject: core: optionally, accept a percentage value for MemoryLimit= and related settings If a percentage is used, it is taken relative to the installed RAM size. This should make it easier to write generic unit files that adapt to the local system. --- man/systemd.resource-control.xml | 36 +++++++++++++++++++----------------- src/core/load-fragment.c | 16 +++++++++++++--- 2 files changed, 32 insertions(+), 20 deletions(-) diff --git a/man/systemd.resource-control.xml b/man/systemd.resource-control.xml index d4c8fa7091..0551d75026 100644 --- a/man/systemd.resource-control.xml +++ b/man/systemd.resource-control.xml @@ -228,9 +228,11 @@ reclaimed as long as memory can be reclaimed from unprotected units. Takes a memory size in bytes. If the value is suffixed with K, M, G or T, the specified memory size is - parsed as Kilobytes, Megabytes, Gigabytes, or Terabytes (with the base 1024), respectively. This controls the - memory.low control group attribute. For details about this control group attribute, see - cgroup-v2.txt. + parsed as Kilobytes, Megabytes, Gigabytes, or Terabytes (with the base 1024), respectively. Alternatively, a + percentage value may be specified, which is taken relative to the installed physical memory on the + system. This controls the memory.low control group attribute. For details about this + control group attribute, see cgroup-v2.txt. Implies MemoryAccounting=true. @@ -247,7 +249,9 @@ aggressively in such cases. This is the main mechanism to control memory usage of a unit. Takes a memory size in bytes. If the value is suffixed with K, M, G or T, the specified memory size is - parsed as Kilobytes, Megabytes, Gigabytes, or Terabytes (with the base 1024), respectively. If assigned the + parsed as Kilobytes, Megabytes, Gigabytes, or Terabytes (with the base 1024), respectively. Alternatively, a + percentage value may be specified, which is taken relative to the installed physical memory on the + system. If assigned the special value infinity, no memory limit is applied. This controls the memory.high control group attribute. For details about this control group attribute, see cgroup-v2.txt. @@ -268,8 +272,9 @@ last line of defense. Takes a memory size in bytes. If the value is suffixed with K, M, G or T, the specified memory size is - parsed as Kilobytes, Megabytes, Gigabytes, or Terabytes (with the base 1024), respectively. If assigned the - special value infinity, no memory limit is applied. This controls the + parsed as Kilobytes, Megabytes, Gigabytes, or Terabytes (with the base 1024), respectively. Alternatively, a + percentage value may be specified, which is taken relative to the installed physical memory on the system. If + assigned the special value infinity, no memory limit is applied. This controls the memory.max control group attribute. For details about this control group attribute, see cgroup-v2.txt. @@ -284,17 +289,14 @@ MemoryLimit=bytes - Specify the limit on maximum memory usage of the - executed processes. The limit specifies how much process and - kernel memory can be used by tasks in this unit. Takes a - memory size in bytes. If the value is suffixed with K, M, G - or T, the specified memory size is parsed as Kilobytes, - Megabytes, Gigabytes, or Terabytes (with the base 1024), - respectively. If assigned the special value - infinity, no memory limit is applied. This - controls the memory.limit_in_bytes - control group attribute. For details about this control - group attribute, see Specify the limit on maximum memory usage of the executed processes. The limit specifies how much + process and kernel memory can be used by tasks in this unit. Takes a memory size in bytes. If the value is + suffixed with K, M, G or T, the specified memory size is parsed as Kilobytes, Megabytes, Gigabytes, or + Terabytes (with the base 1024), respectively. Alternatively, a percentage value may be specified, which is + taken relative to the installed physical memory on the system. If assigned the special value + infinity, no memory limit is applied. This controls the + memory.limit_in_bytes control group attribute. For details about this control group + attribute, see memory.txt. Implies MemoryAccounting=true. diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c index fe60bee789..05852cc7e3 100644 --- a/src/core/load-fragment.c +++ b/src/core/load-fragment.c @@ -2812,9 +2812,19 @@ int config_parse_memory_limit( int r; if (!isempty(rvalue) && !streq(rvalue, "infinity")) { - r = parse_size(rvalue, 1024, &bytes); - if (r < 0 || bytes < 1) { - log_syntax(unit, LOG_ERR, filename, line, r, "Memory limit '%s' invalid. Ignoring.", rvalue); + + r = parse_percent(rvalue); + if (r < 0) { + r = parse_size(rvalue, 1024, &bytes); + if (r < 0) { + log_syntax(unit, LOG_ERR, filename, line, r, "Memory limit '%s' invalid. Ignoring.", rvalue); + return 0; + } + } else + bytes = (((physical_memory() / page_size()) * (uint64_t) r) / 100) * page_size(); + + if (bytes < 1) { + log_syntax(unit, LOG_ERR, filename, line, 0, "Memory limit '%s' too small. Ignoring.", rvalue); return 0; } } -- cgit v1.2.3-54-g00ecf