[systemd-devel] [PATCH] cgroups: Cache controller masks and optimize queues.
david at davidstrauss.net
david at davidstrauss.net
Mon Nov 18 23:04:10 PST 2013
From: David Strauss <david at davidstrauss.net>
---
.gitignore | 1 +
Makefile.am | 13 +++++++
src/core/cgroup.c | 94 +++++++++++++++++++++++++++++++--------------
src/core/cgroup.h | 2 +
src/core/unit.c | 8 +++-
src/core/unit.h | 1 +
src/test/test-cgroup-mask.c | 83 +++++++++++++++++++++++++++++++++++++++
test/daughter.service | 7 ++++
test/parent.slice | 5 +++
test/son.service | 8 ++++
10 files changed, 192 insertions(+), 30 deletions(-)
create mode 100644 src/test/test-cgroup-mask.c
create mode 100644 test/daughter.service
create mode 100644 test/parent.slice
create mode 100644 test/son.service
diff --git a/.gitignore b/.gitignore
index 458cea5..20edf32 100644
--- a/.gitignore
+++ b/.gitignore
@@ -104,6 +104,7 @@
/test-calendarspec
/test-catalog
/test-cgroup
+/test-cgroup-mask
/test-cgroup-util
/test-daemon
/test-date
diff --git a/Makefile.am b/Makefile.am
index 82e46a9..df3e810 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1139,6 +1139,7 @@ tests += \
test-calendarspec \
test-strip-tab-ansi \
test-cgroup-util \
+ test-cgroup-mask \
test-prioq \
test-fileio \
test-time \
@@ -1358,6 +1359,18 @@ test_cgroup_LDADD = \
libsystemd-label.la \
libsystemd-shared.la
+test_cgroup_mask_SOURCES = \
+ src/test/test-cgroup-mask.c
+
+test_cgroup_mask_CFLAGS = \
+ $(AM_CFLAGS) \
+ $(DBUS_CFLAGS) \
+ -D"STR(s)=\#s" -D"TEST_DIR=STR($(abs_top_srcdir)/test/)"
+
+test_cgroup_mask_LDADD = \
+ libsystemd-core.la \
+ $(RT_LIBS)
+
test_cgroup_util_SOURCES = \
src/test/test-cgroup-util.c
diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 1a8fd37..c2b1b7d 100644
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -346,21 +346,8 @@ static CGroupControllerMask unit_get_cgroup_mask(Unit *u) {
}
static CGroupControllerMask unit_get_members_mask(Unit *u) {
- CGroupControllerMask mask = 0;
- Unit *m;
- Iterator i;
-
assert(u);
-
- SET_FOREACH(m, u->dependencies[UNIT_BEFORE], i) {
-
- if (UNIT_DEREF(m->slice) != u)
- continue;
-
- mask |= unit_get_cgroup_mask(m) | unit_get_members_mask(m);
- }
-
- return mask;
+ return u->cgroup_members_mask;
}
static CGroupControllerMask unit_get_siblings_mask(Unit *u) {
@@ -375,6 +362,26 @@ static CGroupControllerMask unit_get_siblings_mask(Unit *u) {
(CGROUP_CPU|CGROUP_BLKIO|CGROUP_CPUACCT);
}
+static CGroupControllerMask unit_get_target_mask(Unit *u) {
+ CGroupControllerMask mask;
+
+ mask = unit_get_cgroup_mask(u) | unit_get_members_mask(u) | unit_get_siblings_mask(u);
+ mask &= u->manager->cgroup_supported;
+
+ return mask;
+}
+
+/* Recurse from a unit up through its containing slices, propagating
+ * mask bits upward. A unit is also member of itself. */
+void unit_update_member_masks(Unit *u) {
+ u->cgroup_members_mask |= unit_get_cgroup_mask(u);
+ if (UNIT_ISSET(u->slice)) {
+ Unit *s = UNIT_DEREF(u->slice);
+ s->cgroup_members_mask |= u->cgroup_members_mask;
+ unit_update_member_masks(s);
+ }
+}
+
static int unit_create_cgroups(Unit *u, CGroupControllerMask mask) {
_cleanup_free_ char *path;
int r;
@@ -422,8 +429,19 @@ static int unit_create_cgroups(Unit *u, CGroupControllerMask mask) {
return 0;
}
+static bool unit_has_mask_realized(Unit *u, CGroupControllerMask mask) {
+ return u->cgroup_realized && u->cgroup_mask == mask;
+}
+
+/* Check if necessary controllers and attributes for a unit are in place.
+ *
+ * If so, do nothing.
+ * If not, create paths, move processes over, and set attributes.
+ *
+ * Returns 0 on success and < 0 on failure. */
static int unit_realize_cgroup_now(Unit *u) {
CGroupControllerMask mask;
+ int r;
assert(u);
@@ -432,19 +450,28 @@ static int unit_realize_cgroup_now(Unit *u) {
u->in_cgroup_queue = false;
}
- mask = unit_get_cgroup_mask(u) | unit_get_members_mask(u) | unit_get_siblings_mask(u);
- mask &= u->manager->cgroup_supported;
+ mask = unit_get_target_mask(u);
- if (u->cgroup_realized &&
- u->cgroup_mask == mask)
+ /* TODO: Consider skipping this check. It may be redundant. */
+ if (unit_has_mask_realized(u, mask))
return 0;
/* First, realize parents */
- if (UNIT_ISSET(u->slice))
- unit_realize_cgroup_now(UNIT_DEREF(u->slice));
+ if (UNIT_ISSET(u->slice)) {
+ r = unit_realize_cgroup_now(UNIT_DEREF(u->slice));
+ if (r < 0)
+ return r;
+ }
/* And then do the real work */
- return unit_create_cgroups(u, mask);
+ r = unit_create_cgroups(u, mask);
+ if (r < 0)
+ return r;
+
+ /* Finally, apply the necessary attributes. */
+ cgroup_context_apply(unit_get_cgroup_context(u), mask, u->cgroup_path);
+
+ return 0;
}
static void unit_add_to_cgroup_queue(Unit *u) {
@@ -459,12 +486,14 @@ static void unit_add_to_cgroup_queue(Unit *u) {
unsigned manager_dispatch_cgroup_queue(Manager *m) {
Unit *i;
unsigned n = 0;
+ int r;
while ((i = m->cgroup_queue)) {
assert(i->in_cgroup_queue);
- if (unit_realize_cgroup_now(i) >= 0)
- cgroup_context_apply(unit_get_cgroup_context(i), i->cgroup_mask, i->cgroup_path);
+ r = unit_realize_cgroup_now(i);
+ if (r < 0)
+ log_warning("Failed to realize cgroups for queued unit %s: %s", i->id, strerror(-r));
n++;
}
@@ -487,9 +516,22 @@ static void unit_queue_siblings(Unit *u) {
if (m == u)
continue;
+ /* Skip units that have a dependency on the slice
+ * but aren't actually in it. */
if (UNIT_DEREF(m->slice) != slice)
continue;
+ /* No point in doing cgroup application for units
+ * without active processes. */
+ if (UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(m)))
+ continue;
+
+ /* If the unit doesn't need any new controllers
+ * and has current ones realized, it doesn't need
+ * any changes. */
+ if (unit_has_mask_realized(m, unit_get_target_mask(m)))
+ continue;
+
unit_add_to_cgroup_queue(m);
}
@@ -521,13 +563,9 @@ int unit_realize_cgroup(Unit *u) {
/* Add all sibling slices to the cgroup queue. */
unit_queue_siblings(u);
- /* And realize this one now */
+ /* And realize this one now (and apply the values) */
r = unit_realize_cgroup_now(u);
- /* And apply the values */
- if (r >= 0)
- cgroup_context_apply(c, u->cgroup_mask, u->cgroup_path);
-
return r;
}
diff --git a/src/core/cgroup.h b/src/core/cgroup.h
index 0a079e9..25f40f7 100644
--- a/src/core/cgroup.h
+++ b/src/core/cgroup.h
@@ -113,3 +113,5 @@ int manager_notify_cgroup_empty(Manager *m, const char *group);
const char* cgroup_device_policy_to_string(CGroupDevicePolicy i) _const_;
CGroupDevicePolicy cgroup_device_policy_from_string(const char *s) _pure_;
+
+void unit_update_member_masks(Unit *u);
diff --git a/src/core/unit.c b/src/core/unit.c
index 7f463f3..7e2f402 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -740,7 +740,8 @@ void unit_dump(Unit *u, FILE *f, const char *prefix) {
"%s\tSlice: %s\n"
"%s\tCGroup: %s\n"
"%s\tCGroup realized: %s\n"
- "%s\tCGroup mask: 0x%x\n",
+ "%s\tCGroup mask: 0x%x\n"
+ "%s\tCGroup members mask: 0x%x\n",
prefix, u->id,
prefix, unit_description(u),
prefix, strna(u->instance),
@@ -756,7 +757,8 @@ void unit_dump(Unit *u, FILE *f, const char *prefix) {
prefix, strna(unit_slice_name(u)),
prefix, strna(u->cgroup_path),
prefix, yes_no(u->cgroup_realized),
- prefix, u->cgroup_mask);
+ prefix, u->cgroup_mask,
+ prefix, u->cgroup_members_mask);
SET_FOREACH(t, u->names, i)
fprintf(f, "%s\tName: %s\n", prefix, t);
@@ -1024,6 +1026,8 @@ int unit_load(Unit *u) {
goto fail;
}
+ unit_update_member_masks(u);
+
r = unit_add_mount_links(u);
if (r < 0)
goto fail;
diff --git a/src/core/unit.h b/src/core/unit.h
index 1a55842..4803925 100644
--- a/src/core/unit.h
+++ b/src/core/unit.h
@@ -174,6 +174,7 @@ struct Unit {
/* Counterparts in the cgroup filesystem */
char *cgroup_path;
CGroupControllerMask cgroup_mask;
+ CGroupControllerMask cgroup_members_mask;
UnitRef slice;
diff --git a/src/test/test-cgroup-mask.c b/src/test/test-cgroup-mask.c
new file mode 100644
index 0000000..ecf041f
--- /dev/null
+++ b/src/test/test-cgroup-mask.c
@@ -0,0 +1,83 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2013 David Strauss
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <pwd.h>
+
+#include "manager.h"
+#include "unit.h"
+#include "util.h"
+#include "macro.h"
+#include "test-helper.h"
+
+static int test_cgroup_mask(void) {
+ Manager *m;
+ Unit *son, *daughter, *parent, *root;
+ FILE *serial = NULL;
+ FDSet *fdset = NULL;
+ int r;
+
+ /* Prepare the manager. */
+ assert_se(set_unit_path(TEST_DIR) >= 0);
+ r = manager_new(SYSTEMD_USER, false, &m);
+ if (r == -EPERM || r == -EACCES) {
+ puts("manager_new: Permission denied. Skipping test.");
+ return EXIT_TEST_SKIP;
+ }
+ assert(r >= 0);
+ assert_se(manager_startup(m, serial, fdset) >= 0);
+
+ /* Load units and verify hierarchy. */
+ assert_se(manager_load_unit(m, "parent.slice", NULL, NULL, &parent) >= 0);
+ assert_se(manager_load_unit(m, "son.service", NULL, NULL, &son) >= 0);
+ assert_se(manager_load_unit(m, "daughter.service", NULL, NULL, &daughter) >= 0);
+ assert(parent->load_state == UNIT_LOADED);
+ assert(son->load_state == UNIT_LOADED);
+ assert(daughter->load_state == UNIT_LOADED);
+ assert(UNIT_DEREF(son->slice) == parent);
+ assert(UNIT_DEREF(daughter->slice) == parent);
+ root = UNIT_DEREF(parent->slice);
+
+ /* Verify per-unit cgroups settings. */
+ assert(cgroup_context_get_mask(unit_get_cgroup_context(son)) == (CGROUP_CPU | CGROUP_CPUACCT));
+ assert(cgroup_context_get_mask(unit_get_cgroup_context(daughter)) == 0);
+ assert(cgroup_context_get_mask(unit_get_cgroup_context(parent)) == CGROUP_BLKIO);
+ assert(cgroup_context_get_mask(unit_get_cgroup_context(root)) == 0);
+
+ /* Verify aggregation of controller masks. */
+ assert(son->cgroup_members_mask == (CGROUP_CPU | CGROUP_CPUACCT));
+ assert(daughter->cgroup_members_mask == 0);
+ assert(parent->cgroup_members_mask == (CGROUP_CPU | CGROUP_CPUACCT | CGROUP_BLKIO));
+ assert(root->cgroup_members_mask == (CGROUP_CPU | CGROUP_CPUACCT | CGROUP_BLKIO));
+
+ manager_free(m);
+
+ return 0;
+}
+
+int main(int argc, char* argv[]) {
+ int rc = 0;
+ TEST_REQ_RUNNING_SYSTEMD(rc = test_cgroup_mask());
+ return rc;
+}
diff --git a/test/daughter.service b/test/daughter.service
new file mode 100644
index 0000000..aebedca
--- /dev/null
+++ b/test/daughter.service
@@ -0,0 +1,7 @@
+[Unit]
+Description=Daughter Service
+
+[Service]
+Slice=parent.slice
+Type=oneshot
+ExecStart=/bin/true
diff --git a/test/parent.slice b/test/parent.slice
new file mode 100644
index 0000000..0222f8e
--- /dev/null
+++ b/test/parent.slice
@@ -0,0 +1,5 @@
+[Unit]
+Description=Parent Slice
+
+[Slice]
+BlockIOWeight=200
diff --git a/test/son.service b/test/son.service
new file mode 100644
index 0000000..50bb96a
--- /dev/null
+++ b/test/son.service
@@ -0,0 +1,8 @@
+[Unit]
+Description=Son Service
+
+[Service]
+Slice=parent.slice
+Type=oneshot
+ExecStart=/bin/true
+CPUShares=100
--
1.8.3.1
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