https://github.com/torvalds/linux
Revision b5b1404d0815894de0690de8a1ab58269e56eae6 authored by Linus Torvalds on 12 August 2018, 19:19:42 UTC, committed by Linus Torvalds on 12 August 2018, 19:19:42 UTC
This is purely a preparatory patch for upcoming changes during the 4.19 merge window. We have a function called "boot_cpu_state_init()" that isn't really about the bootup cpu state: that is done much earlier by the similarly named "boot_cpu_init()" (note lack of "state" in name). This function initializes some hotplug CPU state, and needs to run after the percpu data has been properly initialized. It even has a comment to that effect. Except it _doesn't_ actually run after the percpu data has been properly initialized. On x86 it happens to do that, but on at least arm and arm64, the percpu base pointers are initialized by the arch-specific 'smp_prepare_boot_cpu()' hook, which ran _after_ boot_cpu_state_init(). This had some unexpected results, and in particular we have a patch pending for the merge window that did the obvious cleanup of using 'this_cpu_write()' in the cpu hotplug init code: - per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE; + this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); which is obviously the right thing to do. Except because of the ordering issue, it actually failed miserably and unexpectedly on arm64. So this just fixes the ordering, and changes the name of the function to be 'boot_cpu_hotplug_init()' to make it obvious that it's about cpu hotplug state, because the core CPU state was supposed to have already been done earlier. Marked for stable, since the (not yet merged) patch that will show this problem is marked for stable. Reported-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com> Suggested-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent d6dd643
Tip revision: b5b1404d0815894de0690de8a1ab58269e56eae6 authored by Linus Torvalds on 12 August 2018, 19:19:42 UTC
init: rename and re-order boot_cpu_state_init()
init: rename and re-order boot_cpu_state_init()
Tip revision: b5b1404
show_delta
#!/usr/bin/python
#
# show_deltas: Read list of printk messages instrumented with
# time data, and format with time deltas.
#
# Also, you can show the times relative to a fixed point.
#
# Copyright 2003 Sony Corporation
#
# GPL 2.0 applies.
import sys
import string
def usage():
print ("""usage: show_delta [<options>] <filename>
This program parses the output from a set of printk message lines which
have time data prefixed because the CONFIG_PRINTK_TIME option is set, or
the kernel command line option "time" is specified. When run with no
options, the time information is converted to show the time delta between
each printk line and the next. When run with the '-b' option, all times
are relative to a single (base) point in time.
Options:
-h Show this usage help.
-b <base> Specify a base for time references.
<base> can be a number or a string.
If it is a string, the first message line
which matches (at the beginning of the
line) is used as the time reference.
ex: $ dmesg >timefile
$ show_delta -b NET4 timefile
will show times relative to the line in the kernel output
starting with "NET4".
""")
sys.exit(1)
# returns a tuple containing the seconds and text for each message line
# seconds is returned as a float
# raise an exception if no timing data was found
def get_time(line):
if line[0]!="[":
raise ValueError
# split on closing bracket
(time_str, rest) = string.split(line[1:],']',1)
time = string.atof(time_str)
#print "time=", time
return (time, rest)
# average line looks like:
# [ 0.084282] VFS: Mounted root (romfs filesystem) readonly
# time data is expressed in seconds.useconds,
# convert_line adds a delta for each line
last_time = 0.0
def convert_line(line, base_time):
global last_time
try:
(time, rest) = get_time(line)
except:
# if any problem parsing time, don't convert anything
return line
if base_time:
# show time from base
delta = time - base_time
else:
# just show time from last line
delta = time - last_time
last_time = time
return ("[%5.6f < %5.6f >]" % (time, delta)) + rest
def main():
base_str = ""
filein = ""
for arg in sys.argv[1:]:
if arg=="-b":
base_str = sys.argv[sys.argv.index("-b")+1]
elif arg=="-h":
usage()
else:
filein = arg
if not filein:
usage()
try:
lines = open(filein,"r").readlines()
except:
print ("Problem opening file: %s" % filein)
sys.exit(1)
if base_str:
print ('base= "%s"' % base_str)
# assume a numeric base. If that fails, try searching
# for a matching line.
try:
base_time = float(base_str)
except:
# search for line matching <base> string
found = 0
for line in lines:
try:
(time, rest) = get_time(line)
except:
continue
if string.find(rest, base_str)==1:
base_time = time
found = 1
# stop at first match
break
if not found:
print ('Couldn\'t find line matching base pattern "%s"' % base_str)
sys.exit(1)
else:
base_time = 0.0
for line in lines:
print (convert_line(line, base_time),)
main()
![swh spinner](/static/img/swh-spinner.gif)
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