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=== Description (from pull-request) ===
Signed-off-by: Christian Brauner <christian.brau...@ubuntu.com>
From 77b37202eb163069ee202c73ad32f4f2d4a340af Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brau...@ubuntu.com>
Date: Thu, 5 Nov 2020 19:19:41 +0100
Subject: [PATCH 1/2] cgfsng: align method implementations
Signed-off-by: Christian Brauner <christian.brau...@ubuntu.com>
---
src/cgroups/cgfsng.c | 38 +++++++++++++++++++-------------------
1 file changed, 19 insertions(+), 19 deletions(-)
diff --git a/src/cgroups/cgfsng.c b/src/cgroups/cgfsng.c
index 824b0e7..2d09f88 100644
--- a/src/cgroups/cgfsng.c
+++ b/src/cgroups/cgfsng.c
@@ -992,33 +992,33 @@ struct cgroup_ops *cgfsng_ops_init(void)
if (!cgfsng_ops)
return ret_set_errno(NULL, ENOMEM);
- cgfsng_ops->cgroup_layout = CGROUP_LAYOUT_UNKNOWN;
- cgfsng_ops->mntns_fd = -EBADF;
- cgfsng_ops->cgroup2_root_fd = -EBADF;
+ cgfsng_ops->cgroup_layout = CGROUP_LAYOUT_UNKNOWN;
+ cgfsng_ops->mntns_fd = -EBADF;
+ cgfsng_ops->cgroup2_root_fd = -EBADF;
if (cg_init(cgfsng_ops))
return NULL;
- cgfsng_ops->num_hierarchies = cgfsng_num_hierarchies;
- cgfsng_ops->get = cgfsng_get;
- cgfsng_ops->get_hierarchies = cgfsng_get_hierarchies;
- cgfsng_ops->get_hierarchy = cgfsng_get_hierarchy;
- cgfsng_ops->driver = "cgfsng";
- cgfsng_ops->version = "1.0.0";
- cgfsng_ops->mount = cgfsng_mount;
+ cgfsng_ops->num_hierarchies = cgfsng_num_hierarchies;
+ cgfsng_ops->get = cgfsng_get;
+ cgfsng_ops->get_hierarchies = cgfsng_get_hierarchies;
+ cgfsng_ops->get_hierarchy = cgfsng_get_hierarchy;
+ cgfsng_ops->driver = "cgfsng";
+ cgfsng_ops->version = "1.0.0";
+ cgfsng_ops->mount = cgfsng_mount;
/* memory */
- cgfsng_ops->get_memory_stats_fd = cgfsng_get_memory_stats_fd;
- cgfsng_ops->get_memory_stats = cgfsng_get_memory_stats;
- cgfsng_ops->get_memory_max = cgfsng_get_memory_max;
- cgfsng_ops->get_memory_swap_max = cgfsng_get_memory_swap_max;
- cgfsng_ops->get_memory_current = cgfsng_get_memory_current;
- cgfsng_ops->get_memory_swap_current = cgfsng_get_memory_swap_current;
- cgfsng_ops->can_use_swap = cgfsng_can_use_swap;
+ cgfsng_ops->get_memory_stats_fd = cgfsng_get_memory_stats_fd;
+ cgfsng_ops->get_memory_stats = cgfsng_get_memory_stats;
+ cgfsng_ops->get_memory_max = cgfsng_get_memory_max;
+ cgfsng_ops->get_memory_swap_max = cgfsng_get_memory_swap_max;
+ cgfsng_ops->get_memory_current = cgfsng_get_memory_current;
+ cgfsng_ops->get_memory_swap_current =
cgfsng_get_memory_swap_current;
+ cgfsng_ops->can_use_swap = cgfsng_can_use_swap;
/* cpuset */
- cgfsng_ops->get_cpuset_cpus = cgfsng_get_cpuset_cpus;
- cgfsng_ops->can_use_cpuview = cgfsng_can_use_cpuview;
+ cgfsng_ops->get_cpuset_cpus = cgfsng_get_cpuset_cpus;
+ cgfsng_ops->can_use_cpuview = cgfsng_can_use_cpuview;
/* blkio */
cgfsng_ops->get_io_service_bytes = cgfsng_get_io_service_bytes;
From 3b9c3c53ee34b908636b534f3eb2807d817f4765 Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brau...@ubuntu.com>
Date: Thu, 5 Nov 2020 20:21:00 +0100
Subject: [PATCH 2/2] meminfo: align swap implementation with docs
Signed-off-by: Christian Brauner <christian.brau...@ubuntu.com>
---
src/cgroups/cgfsng.c | 7 +++++++
src/cgroups/cgroup.h | 2 ++
src/proc_fuse.c | 45 ++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 52 insertions(+), 2 deletions(-)
diff --git a/src/cgroups/cgfsng.c b/src/cgroups/cgfsng.c
index 2d09f88..b369ed2 100644
--- a/src/cgroups/cgfsng.c
+++ b/src/cgroups/cgfsng.c
@@ -602,6 +602,12 @@ static int cgfsng_get_memory_stats_fd(struct cgroup_ops
*ops, const char *cgroup
return openat(h->fd, path, O_RDONLY | O_CLOEXEC | O_NOFOLLOW);
}
+static int cgfsng_get_memory_swappiness(struct cgroup_ops *ops,
+ const char *cgroup, char **value)
+{
+ return cgfsng_get_memory(ops, cgroup, "memory.swappiness", value);
+}
+
static int cgfsng_get_memory_current(struct cgroup_ops *ops, const char
*cgroup,
char **value)
{
@@ -1014,6 +1020,7 @@ struct cgroup_ops *cgfsng_ops_init(void)
cgfsng_ops->get_memory_swap_max = cgfsng_get_memory_swap_max;
cgfsng_ops->get_memory_current = cgfsng_get_memory_current;
cgfsng_ops->get_memory_swap_current =
cgfsng_get_memory_swap_current;
+ cgfsng_ops->get_memory_swappiness = cgfsng_get_memory_swappiness;
cgfsng_ops->can_use_swap = cgfsng_can_use_swap;
/* cpuset */
diff --git a/src/cgroups/cgroup.h b/src/cgroups/cgroup.h
index ad4a3ae..ba29b97 100644
--- a/src/cgroups/cgroup.h
+++ b/src/cgroups/cgroup.h
@@ -153,6 +153,8 @@ struct cgroup_ops {
char **value);
int (*get_memory_swap_max)(struct cgroup_ops *ops, const char *cgroup,
char **value);
+ int (*get_memory_swappiness)(struct cgroup_ops *ops, const char *cgroup,
+ char **value);
bool (*can_use_swap)(struct cgroup_ops *ops);
/* cpuset */
diff --git a/src/proc_fuse.c b/src/proc_fuse.c
index 7bc1eb0..0d24b9e 100644
--- a/src/proc_fuse.c
+++ b/src/proc_fuse.c
@@ -310,6 +310,15 @@ static uint64_t get_min_memlimit(const char *cgroup, bool
swap)
return retlimit;
}
+static bool swappiness_is_off(const char *cgroup)
+{
+ __do_free char *swappiness_str = NULL;
+ int ret;
+
+ ret = cgroup_ops->get_memory_swappiness(cgroup_ops, cgroup,
&swappiness_str);
+ return (ret > 0) && swappiness_str && (*swappiness_str == '0');
+}
+
static inline bool startswith(const char *line, const char *pref)
{
return strncmp(line, pref, strlen(pref)) == 0;
@@ -1141,7 +1150,8 @@ static int proc_meminfo_read(char *buf, size_t size,
off_t offset,
__do_fclose FILE *f = NULL;
struct fuse_context *fc = fuse_get_context();
struct lxcfs_opts *opts = (struct lxcfs_opts
*)fuse_get_context()->private_data;
- bool wants_swap = opts && !opts->swap_off && liblxcfs_can_use_swap(),
host_swap = false;
+ bool wants_swap = opts && !opts->swap_off && liblxcfs_can_use_swap(),
host_swap = false,
+ swappiness_off = false;
struct file_info *d = INTTYPE_TO_PTR(fi->fh);
uint64_t memlimit = 0, memusage = 0, memswlimit = 0, memswusage = 0,
hosttotal = 0, swfree = 0, swusage = 0, swtotal = 0;
@@ -1195,6 +1205,7 @@ static int proc_meminfo_read(char *buf, size_t size,
off_t offset,
* turned off for current kernel.
*/
if (wants_swap) {
+ swappiness_off = swappiness_is_off(cgroup);
memswlimit = get_min_memlimit(cgroup, true);
if (memswlimit > 0) {
ret = cgroup_ops->get_memory_swap_current(cgroup_ops,
cgroup, &memswusage_str);
@@ -1209,6 +1220,36 @@ static int proc_meminfo_read(char *buf, size_t size,
off_t offset,
swusage = (memswusage - memusage) /
1024;
}
}
+
+ /*
+ * If the swappiness is set to 0 and there is no SWAP usage, no
+ * SWAP is reported. However if there is SWAP usage, then a
+ * SWAP device of the size of the usage (100% full) is
+ * reported. This provides adequate reporting of the memory
+ * consumption while preventing applications from assuming more
+ * SWAP is available.
+ */
+ if (swappiness_off) {
+ if (swusage == 0) {
+ wants_swap = false;
+ } else {
+ swtotal = swusage;
+ swfree = 0;
+ }
+ }
+
+ /*
+ * Because SWAP usage for a given container can exceed the
+ * delta between RAM and RAM+SWAP, the SWAP size is always
+ * reported to be the smaller of the RAM+SWAP limit or the host
+ * SWAP device itself. This ensures that at no point SWAP usage
+ * will be allowed to exceed the SWAP size.
+ */
+ if (wants_swap && (swtotal > memlimit)) {
+ swtotal = memlimit;
+ swusage = memlimit;
+ swfree = 0;
+ }
}
f = fopen_cached("/proc/meminfo", "re", &fopen_cache);
@@ -1253,7 +1294,7 @@ static int proc_meminfo_read(char *buf, size_t size,
off_t offset,
* anyway.) so fallback to the host's values in
* that case too.
*/
- if ((hostswtotal < swtotal) || swtotal == 0) {
+ if ((hostswtotal < swtotal)) {
swtotal = hostswtotal;
host_swap = true;
}
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