v01: core: add MemorySwapLimit= to limit memory+swap#2171
Closed
walyong wants to merge 1 commit intosystemd:masterfrom
walyong:memcg_v01
Closed
v01: core: add MemorySwapLimit= to limit memory+swap#2171walyong wants to merge 1 commit intosystemd:masterfrom walyong:memcg_v01
walyong wants to merge 1 commit intosystemd:masterfrom
walyong:memcg_v01
Conversation
Similar to MemoryLimit=, MemorySwapLimit= limits memory+swap usage. This controls the "memory.memsw.limit_in_bytes" control group attribute. And when MemorySwapLimit= was set, if MemoryLimit= was not set or bigger than MemorySwapLimit= then set MemoryLimit= as same amount of value with MemorySwapLimit=.
Contributor
|
Are there any tests? |
Contributor
Author
|
I wrote local test code memory-swap-limit-test.c: #define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <limits.h>
static int get_memory_cgroup_of_my(char **path) {
char *p = NULL, *proc_cgroup = NULL;
pid_t pid = getpid();
char buf[LINE_MAX];
FILE *f = NULL;
asprintf(&proc_cgroup, "/proc/%d/cgroup", pid);
f = fopen(proc_cgroup, "re");
if (!f)
return -errno;
for (;;) {
char *name = NULL;
int i;
if (!fgets(buf, sizeof(buf), f)) {
if (ferror(f))
return -errno;
break;
}
sscanf(buf, "%d:%m[^:]:%ms", &i, &name, &p);
if (!strcmp(name, "memory")) {
*path = p;
free(proc_cgroup);
fclose(f);
return 0;
}
}
free(proc_cgroup);
fclose(f);
return -ENODATA;
}
static int find_cgroup_path(char **path) {
char *cg_node = NULL;
char *p = NULL;
int r;
r = get_memory_cgroup_of_my(&cg_node);
if (r < 0)
return r;
if (!strcmp(cg_node, "/")) {
fprintf(stderr, "Should be run as systemd service\n");
free(cg_node);
return -ENOTSUP;
}
asprintf(&p, "/sys/fs/cgroup/memory%s", cg_node);
*path = p;
free(cg_node);
return 0;
}
static void display_memcg_info(const char *path) {
char *list[] = {
"memory.usage_in_bytes",
"memory.limit_in_bytes",
"memory.failcnt",
"memory.memsw.usage_in_bytes",
"memory.memsw.limit_in_bytes",
"memory.memsw.failcnt",
NULL
};
char node[PATH_MAX];
char buf[LINE_MAX];
int i;
for (i = 0; list[i] != NULL; i++) {
FILE *f = NULL;
snprintf(node, PATH_MAX, "%s/%s", path, list[i]);
f = fopen(node, "re");
for (;;) {
if (!fgets(buf, sizeof(buf), f))
break;
printf("%s: %s\n",list[i], buf);
}
fclose(f);
}
}
int main(int argc, char *argv[]) {
char *cg_path = NULL;
void *p = NULL;
int i, r;
r = find_cgroup_path(&cg_path);
if (r < 0)
return EXIT_FAILURE;
printf("cgroup path: %s\n", cg_path);
display_memcg_info(cg_path);
for (i = 0;; i++) {
p = malloc(500 << 10);
if (!p) {
fprintf(stderr, "!!! malloc failed: %s\n", strerror(errno));
continue;
}
memset(p, 0x0, 500 << 10);
fprintf(stdout, "!!! malloc successed. Count %d\n", i+1);
display_memcg_info(cg_path);
sleep(1);
}
return 0;
}And also I wrote a service file to test as memory-swap-limit-test.service: [Unit]
Description=Test MemorySwapLimit=
[Service]
ExecStart=/home/walyong/tmp/memory-swap-limit/memory-swap-limit-test
MemoryLimit=5M
MemorySwapLimit=10M
StandardOutput=journal
StandardError=inheritAnd run: [root@laptop system]# systemctl daemon-reload
[root@laptop system]# systemctl start memory-swap-limit.service; systemctl status memory-swap-limit.service
● memory-swap-limit.service - Test MemorySwapLimit=
Loaded: loaded (/usr/lib/systemd/system/memory-swap-limit.service; static; vendor preset: disabled)
Active: active (running) since Wed 2015-12-16 13:37:44 KST; 96ms ago
Main PID: 14870 (memory-swap-lim)
Memory: 596.0K (limit: 5.0M) (with swap limit: 10.0M)
CGroup: /system.slice/memory-swap-limit.service
└─14870 /home/walyong/tmp/memory-swap-limit/memory-swap-limit-test
Dec 16 13:37:44 laptop.walyong.com systemd[1]: Started Test MemorySwapLimit=.Finally, I can get below logs: And I'd also tested with only MemoryLimit= option: [Unit]
Description=Test MemorySwapLimit=
[Service]
ExecStart=/home/walyong/tmp/memory-swap-limit/memory-swap-limit-test
MemoryLimit=5M
StandardOutput=journal
StandardError=inheritThen, the service was not killed well: So I had to stop that. |
Member
|
At this point, I don't think we should support cgroups properties that have no future in the unified hierarchy. Or does this one have a counterpart on the unified hierarchy? |
poettering
added
cgroups
pid1
needs-reporter-feedback ❓
Contributor
Author
|
It seems currently being implemented now: I will create new PR after kernel has facility for accounting swap. |
Member
|
Well, basically, I think we shouldn't add new support for something that has no future. I am fine howeve, to add support for something that has a clear future and then adding compat for old setups, if that's possible. Or in other words, as soon as it is clear how the settings will look like in the unified hierarchy, we can add support for this setting, and then also make it work on the legacy hierararchy too. But I am not keen on adding support for the legacy hierarchy before the unified hierarchy support is clear, because the exposed knobs should follow the new design, not the old design. I hope this makes sense? Let's delay this until the swap memory knobs land in the kernel hence! Sorry! |
poettering
added
postponed
and removed
needs-reporter-feedback ❓
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Similar to MemoryLimit=, MemorySwapLimit= limits memory+swap usage. This
controls the "memory.memsw.limit_in_bytes" control group attribute.
And when MemorySwapLimit= was set, if MemoryLimit= was not set or bigger
than MemorySwapLimit= then set MemoryLimit= as same amount of
value with MemorySwapLimit=.
https://www.kernel.org/doc/Documentation/cgroups/memory.txt: