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authorLennart Poettering <lennart@poettering.net>2016-06-08 20:45:32 +0200
committerLennart Poettering <lennart@poettering.net>2016-06-14 20:01:45 +0200
commitd8cf2ac79b524d7784bccb428295ebc9c5e8548c (patch)
tree43a03ab780ccc0b130dc57322c816f99e3f09754 /src
parent799ec13412e2f6649fd69ce4f1ca1674a40039b0 (diff)
util: introduce physical_memory_scale() to unify how we scale by physical memory
The various bits of code did the scaling all different, let's unify this, given that the code is not trivial.
Diffstat (limited to 'src')
-rw-r--r--src/basic/util.c27
-rw-r--r--src/basic/util.h1
-rw-r--r--src/core/load-fragment.c2
-rw-r--r--src/login/logind-user.c2
-rw-r--r--src/login/logind.c2
-rw-r--r--src/test/test-util.c38
6 files changed, 68 insertions, 4 deletions
diff --git a/src/basic/util.c b/src/basic/util.c
index 88d58cd94a..09d16697b7 100644
--- a/src/basic/util.c
+++ b/src/basic/util.c
@@ -805,6 +805,33 @@ uint64_t physical_memory(void) {
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;
+}
+
int update_reboot_parameter_and_warn(const char *param) {
int r;
diff --git a/src/basic/util.h b/src/basic/util.h
index 9e6df19ef1..db105197e8 100644
--- a/src/basic/util.h
+++ b/src/basic/util.h
@@ -184,6 +184,7 @@ int namespace_open(pid_t pid, int *pidns_fd, int *mntns_fd, int *netns_fd, int *
int namespace_enter(int pidns_fd, int mntns_fd, int netns_fd, int userns_fd, int root_fd);
uint64_t physical_memory(void);
+uint64_t physical_memory_scale(uint64_t v, uint64_t max);
int update_reboot_parameter_and_warn(const char *param);
diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
index 05852cc7e3..58d7275a96 100644
--- a/src/core/load-fragment.c
+++ b/src/core/load-fragment.c
@@ -2821,7 +2821,7 @@ int config_parse_memory_limit(
return 0;
}
} else
- bytes = (((physical_memory() / page_size()) * (uint64_t) r) / 100) * page_size();
+ bytes = physical_memory_scale(r, 100U);
if (bytes < 1) {
log_syntax(unit, LOG_ERR, filename, line, 0, "Memory limit '%s' too small. Ignoring.", rvalue);
diff --git a/src/login/logind-user.c b/src/login/logind-user.c
index 6d0904f5ca..de44d369cf 100644
--- a/src/login/logind-user.c
+++ b/src/login/logind-user.c
@@ -853,7 +853,7 @@ int config_parse_tmpfs_size(
/* First, try to parse as percentage */
r = parse_percent(rvalue);
if (r > 0 && r < 100)
- *sz = PAGE_ALIGN((size_t) ((physical_memory() * (uint64_t) r) / 100U));
+ *sz = physical_memory_scale(r, 100U);
else {
uint64_t k;
diff --git a/src/login/logind.c b/src/login/logind.c
index caf149cfb7..d01dd110ea 100644
--- a/src/login/logind.c
+++ b/src/login/logind.c
@@ -61,7 +61,7 @@ static void manager_reset_config(Manager *m) {
m->idle_action_usec = 30 * USEC_PER_MINUTE;
m->idle_action = HANDLE_IGNORE;
- m->runtime_dir_size = PAGE_ALIGN((size_t) (physical_memory() / 10)); /* 10% */
+ m->runtime_dir_size = physical_memory_scale(10U, 100U); /* 10% */
m->user_tasks_max = 12288;
m->sessions_max = 8192;
m->inhibitors_max = 8192;
diff --git a/src/test/test-util.c b/src/test/test-util.c
index 5b3fbcff53..e177612a9f 100644
--- a/src/test/test-util.c
+++ b/src/test/test-util.c
@@ -273,7 +273,42 @@ static void test_physical_memory(void) {
assert_se(p < UINT64_MAX);
assert_se(p % page_size() == 0);
- log_info("Memory: %s", format_bytes(buf, sizeof(buf), p));
+ log_info("Memory: %s (%" PRIu64 ")", format_bytes(buf, sizeof(buf), p), p);
+}
+
+static void test_physical_memory_scale(void) {
+ uint64_t p;
+
+ p = physical_memory();
+
+ assert_se(physical_memory_scale(0, 100) == 0);
+ assert_se(physical_memory_scale(100, 100) == p);
+
+ log_info("Memory original: %" PRIu64, physical_memory());
+ log_info("Memory scaled by 50%%: %" PRIu64, physical_memory_scale(50, 100));
+ log_info("Memory divided by 2: %" PRIu64, physical_memory() / 2);
+ log_info("Page size: %zu", page_size());
+
+ /* There might be an uneven number of pages, hence permit these calculations to be half a page off... */
+ assert_se(page_size()/2 + physical_memory_scale(50, 100) - p/2 <= page_size());
+ assert_se(physical_memory_scale(200, 100) == p*2);
+
+ assert_se(physical_memory_scale(0, 1) == 0);
+ assert_se(physical_memory_scale(1, 1) == p);
+ assert_se(physical_memory_scale(2, 1) == p*2);
+
+ assert_se(physical_memory_scale(0, 2) == 0);
+
+ assert_se(page_size()/2 + physical_memory_scale(1, 2) - p/2 <= page_size());
+ assert_se(physical_memory_scale(2, 2) == p);
+ assert_se(physical_memory_scale(4, 2) == p*2);
+
+ assert_se(physical_memory_scale(0, UINT32_MAX) == 0);
+ assert_se(physical_memory_scale(UINT32_MAX, UINT32_MAX) == p);
+
+ /* overflow */
+ assert_se(physical_memory_scale(UINT64_MAX/4, UINT64_MAX) == UINT64_MAX);
+
}
int main(int argc, char *argv[]) {
@@ -291,6 +326,7 @@ int main(int argc, char *argv[]) {
test_execute_directory();
test_raw_clone();
test_physical_memory();
+ test_physical_memory_scale();
return 0;
}