From 2cb7e0aaedad73b076ea18c6900b0e86c5760d79 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 15:00:47 +0200 Subject: Adding upstream version 247.3. Signed-off-by: Daniel Baumann --- src/basic/limits-util.c | 154 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 154 insertions(+) create mode 100644 src/basic/limits-util.c (limited to 'src/basic/limits-util.c') diff --git a/src/basic/limits-util.c b/src/basic/limits-util.c new file mode 100644 index 0000000..259c311 --- /dev/null +++ b/src/basic/limits-util.c @@ -0,0 +1,154 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include "alloc-util.h" +#include "cgroup-util.h" +#include "limits-util.h" +#include "memory-util.h" +#include "parse-util.h" +#include "process-util.h" +#include "procfs-util.h" +#include "string-util.h" + +uint64_t physical_memory(void) { + _cleanup_free_ char *root = NULL, *value = NULL; + uint64_t mem, lim; + size_t ps; + long sc; + int r; + + /* We return this as uint64_t in case we are running as 32bit process on a 64bit kernel with huge amounts of + * memory. + * + * In order to support containers nicely that have a configured memory limit we'll take the minimum of the + * physically reported amount of memory and the limit configured for the root cgroup, if there is any. */ + + sc = sysconf(_SC_PHYS_PAGES); + assert(sc > 0); + + ps = page_size(); + mem = (uint64_t) sc * (uint64_t) ps; + + r = cg_get_root_path(&root); + if (r < 0) { + log_debug_errno(r, "Failed to determine root cgroup, ignoring cgroup memory limit: %m"); + return mem; + } + + r = cg_all_unified(); + if (r < 0) { + log_debug_errno(r, "Failed to determine root unified mode, ignoring cgroup memory limit: %m"); + return mem; + } + if (r > 0) { + r = cg_get_attribute("memory", root, "memory.max", &value); + if (r == -ENOENT) /* Field does not exist on the system's top-level cgroup, hence don't + * complain. (Note that it might exist on our own root though, if we live + * in a cgroup namespace, hence check anyway instead of not even + * trying.) */ + return mem; + if (r < 0) { + log_debug_errno(r, "Failed to read memory.max cgroup attribute, ignoring cgroup memory limit: %m"); + return mem; + } + + if (streq(value, "max")) + return mem; + } else { + r = cg_get_attribute("memory", root, "memory.limit_in_bytes", &value); + if (r < 0) { + log_debug_errno(r, "Failed to read memory.limit_in_bytes cgroup attribute, ignoring cgroup memory limit: %m"); + return mem; + } + } + + r = safe_atou64(value, &lim); + if (r < 0) { + log_debug_errno(r, "Failed to parse cgroup memory limit '%s', ignoring: %m", value); + return mem; + } + if (lim == UINT64_MAX) + return mem; + + /* Make sure the limit is a multiple of our own page size */ + lim /= ps; + lim *= ps; + + return MIN(mem, lim); +} + +uint64_t physical_memory_scale(uint64_t v, uint64_t max) { + uint64_t p, m, ps, r; + + assert(max > 0); + + /* Returns the physical memory size, multiplied by v divided by max. Returns UINT64_MAX on overflow. On success + * the result is a multiple of the page size (rounds down). */ + + ps = page_size(); + assert(ps > 0); + + p = physical_memory() / ps; + assert(p > 0); + + m = p * v; + if (m / p != v) + return UINT64_MAX; + + m /= max; + + r = m * ps; + if (r / ps != m) + return UINT64_MAX; + + return r; +} + +uint64_t system_tasks_max(void) { + uint64_t a = TASKS_MAX, b = TASKS_MAX; + _cleanup_free_ char *root = NULL; + int r; + + /* Determine the maximum number of tasks that may run on this system. We check three sources to determine this + * limit: + * + * a) the maximum tasks value the kernel allows on this architecture + * b) the cgroups pids_max attribute for the system + * c) the kernel's configured maximum PID value + * + * And then pick the smallest of the three */ + + r = procfs_tasks_get_limit(&a); + if (r < 0) + log_debug_errno(r, "Failed to read maximum number of tasks from /proc, ignoring: %m"); + + r = cg_get_root_path(&root); + if (r < 0) + log_debug_errno(r, "Failed to determine cgroup root path, ignoring: %m"); + else { + r = cg_get_attribute_as_uint64("pids", root, "pids.max", &b); + if (r < 0) + log_debug_errno(r, "Failed to read pids.max attribute of cgroup root, ignoring: %m"); + } + + return MIN3(TASKS_MAX, + a <= 0 ? TASKS_MAX : a, + b <= 0 ? TASKS_MAX : b); +} + +uint64_t system_tasks_max_scale(uint64_t v, uint64_t max) { + uint64_t t, m; + + assert(max > 0); + + /* Multiply the system's task value by the fraction v/max. Hence, if max==100 this calculates percentages + * relative to the system's maximum number of tasks. Returns UINT64_MAX on overflow. */ + + t = system_tasks_max(); + assert(t > 0); + + m = t * v; + if (m / t != v) /* overflow? */ + return UINT64_MAX; + + return m / max; +} -- cgit v1.2.3