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-rw-r--r--lib/_emerge/actions.py48
-rw-r--r--man/make.conf.510
2 files changed, 54 insertions, 4 deletions
diff --git a/lib/_emerge/actions.py b/lib/_emerge/actions.py
index 1946f49df..df5c86c6c 100644
--- a/lib/_emerge/actions.py
+++ b/lib/_emerge/actions.py
@@ -14,6 +14,7 @@ import textwrap
import time
import warnings
from itertools import chain
+from pathlib import Path
import portage
portage.proxy.lazyimport.lazyimport(globals(),
@@ -2634,14 +2635,55 @@ def apply_priorities(settings):
nice(settings)
def nice(settings):
+ nice_value: str = settings.get("PORTAGE_NICENESS", "").strip()
+ if not nice_value:
+ return
+
try:
- os.nice(int(settings.get("PORTAGE_NICENESS", "0")))
+ current_nice_value = os.nice(int(nice_value))
+ # Calling os.nice() with a value outside of the valid range of
+ # nice values, e.g. 20, caps the process's nice value. This is
+ # because the argument of os.nice() is not an absolute value,
+ # but the increment to the process's current nice
+ # value. Hence users may use PORTAGE_NICENESS=20 without any
+ # issues here. However, below we write nice_value potentially
+ # to /proc/self/autogroup, which will only accept valid nice
+ # values. Therefore we simply set nice_value to what os.nice()
+ # returned (i.e. the process's current nice value).
+ nice_value = str(current_nice_value)
except (OSError, ValueError) as e:
out = portage.output.EOutput()
- out.eerror("Failed to change nice value to '%s'" % \
- settings.get("PORTAGE_NICENESS", "0"))
+ out.eerror(f"Failed to change nice value to {nice_value}")
out.eerror("%s\n" % str(e))
+ autogroup_file = Path("/proc/self/autogroup")
+ try:
+ f = autogroup_file.open("r+")
+ except EnvironmentError:
+ # Autogroup scheduling is not enabled on this system.
+ return
+
+ with f:
+ line = f.readline()
+ original_autogroup_nice_value = line.split(" ")[2]
+
+ # We need to restore the original nice value of the
+ # autogroup, as otherwise the session, e.g. the
+ # terminal where portage was executed in, would
+ # continue running with that value.
+ portage.atexit_register(
+ lambda value: autogroup_file.write_text(value),
+ original_autogroup_nice_value,
+ )
+
+ try:
+ f.write(nice_value)
+ except EnvironmentError as e:
+ out = portage.output.EOutput()
+ out.eerror(f"Failed to change autogroup's nice value to {nice_value}")
+ out.eerror("%s\n" % str(e))
+
+
def ionice(settings):
ionice_cmd = settings.get("PORTAGE_IONICE_COMMAND")
diff --git a/man/make.conf.5 b/man/make.conf.5
index 1c72109ad..18573b5e2 100644
--- a/man/make.conf.5
+++ b/man/make.conf.5
@@ -1,4 +1,4 @@
-.TH "MAKE.CONF" "5" "May 2021" "Portage VERSION" "Portage"
+.TH "MAKE.CONF" "5" "Jun 2021" "Portage VERSION" "Portage"
.SH "NAME"
make.conf \- custom settings for Portage
.SH "SYNOPSIS"
@@ -1031,6 +1031,14 @@ The value of this variable will be added to the current nice level that
emerge is running at. In other words, this will not set the nice level,
it will increment it. For more information about nice levels and what
are acceptable ranges, see \fBnice\fR(1).
+.br
+If set and portage is run under Linux with autogroup scheduling (see
+\fBsched\fR(7)) enabled, then portage will set the nice value of its
+autogroup to PORTAGE_NICENESS. Upon exiting, portage will restore the
+original value. Note that if the function responsible for restoring the
+original value is not run, e.g., because portage's process was killed,
+then the autogroup will stay niced. In such a case, the value can be
+reset via corresponding autogroup pseudo\-file in /proc.
.TP
\fBPORTAGE_RO_DISTDIRS\fR = \fI[space delimited list of directories]\fR
When a given file does not exist in \fBDISTDIR\fR, search for the file