[PATCH] bitbake.conf: update way of setting XZ_MEMLIMIT

["Changqing Li" <changqing.li@windriver.com>]

From: Changqing Li <changqing.li@windriver.com>

Update way of setting XZ_MEMLIMIT, considering scenario that
running bitbake in container, to avoid OOM Killer of xz.

For example:
Container has memory limit of 30G, and host memory is 300G.  'xz
--memlimit=50% ...' will get host memory, so the limit for xz is 150G.
And because of the container memory limit is 30G, xz can use nearly up
to 30G memory, which may cause oom kill of xz.

Signed-off-by: Changqing Li <changqing.li@windriver.com>
---
 meta/conf/bitbake.conf |  3 ++-
 meta/lib/oe/utils.py   | 12 ++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/meta/conf/bitbake.conf b/meta/conf/bitbake.conf
index f6fb2aa698..2b36e083ca 100644
--- a/meta/conf/bitbake.conf
+++ b/meta/conf/bitbake.conf
@@ -809,7 +809,8 @@ BB_NUMBER_THREADS ?= "${@oe.utils.cpu_count()}"
 PARALLEL_MAKE ?= "-j ${@oe.utils.cpu_count()}"
 
 # Default parallelism and resource usage for xz
-XZ_MEMLIMIT ?= "50%"
+CONTAINER_MEM_LIMIT = "${@oe.utils.container_mem_limit()}"
+XZ_MEMLIMIT ?= "${@ '%d' % (int(d.getVar('CONTAINER_MEM_LIMIT'))/2) if d.getVar('CONTAINER_MEM_LIMIT') != '0' else '50%'}"
 XZ_THREADS ?= "${@oe.utils.cpu_count(at_least=2)}"
 XZ_DEFAULTS ?= "--memlimit=${XZ_MEMLIMIT} --threads=${XZ_THREADS}"
 XZ_DEFAULTS[vardepsexclude] += "XZ_MEMLIMIT XZ_THREADS"
diff --git a/meta/lib/oe/utils.py b/meta/lib/oe/utils.py
index a84039f585..581072ac0d 100644
--- a/meta/lib/oe/utils.py
+++ b/meta/lib/oe/utils.py
@@ -252,6 +252,18 @@ def cpu_count(at_least=1):
     cpus = len(os.sched_getaffinity(0))
     return max(cpus, at_least)
 
+def container_mem_limit():
+    limit_in_bytes = '0'
+    proc_sched = '/proc/1/sched'
+    if os.path.exists(proc_sched):
+        with open(proc_sched, 'r') as fp:
+            initinfo = fp.readline().strip()
+            cgroup_limit_in_bytes = '/sys/fs/cgroup/memory/memory.limit_in_bytes'
+            if initinfo.split(' ')[0] not in ('systemd', 'init',) and os.path.exists(cgroup_limit_in_bytes):
+                with open(cgroup_limit_in_bytes) as fpc:
+                    limit_in_bytes=fpc.readline().strip()
+    return limit_in_bytes
+
 def execute_pre_post_process(d, cmds):
     if cmds is None:
         return
-- 
2.17.1