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| author |  Anton Ivanov <aivanov@brocade.com>
| 2015-11-02 16:16:37 +0000 |
|---|---|---|
| committer |  Richard Weinberger <richard@nod.at>
| 2015-11-06 22:54:49 +0100 |
| commit | 2eb5f31bc4ea24bb293e82934cfa1cce9573304b (patch) | |
| tree | 69c2d1f775babd528d0873660c97d78f52318641 /arch/um/os-Linux/main.c | |
| parent | um: net: replace GFP_KERNEL with GFP_ATOMIC when spinlock is held (diff) | |
| download | linux-2eb5f31bc4ea24bb293e82934cfa1cce9573304b.tar.gz linux-2eb5f31bc4ea24bb293e82934cfa1cce9573304b.tar.bz2 linux-2eb5f31bc4ea24bb293e82934cfa1cce9573304b.zip | |
um: Switch clocksource to hrtimers
UML is using an obsolete itimer call for
all timers and "polls" for kernel space timer firing
in its userspace portion resulting in a long list
of bugs and incorrect behaviour(s). It also uses
ITIMER_VIRTUAL for its timer which results in the
timer being dependent on it running and the cpu
load.
This patch fixes this by moving to posix high resolution
timers firing off CLOCK_MONOTONIC and relaying the timer
correctly to the UML userspace.
Fixes:
- crashes when hosts suspends/resumes
- broken userspace timers - effecive ~40Hz instead
of what they should be. Note - this modifies skas behavior
by no longer setting an itimer per clone(). Timer events
are relayed instead.
- kernel network packet scheduling disciplines
- tcp behaviour especially under load
- various timer related corner cases
Finally, overall responsiveness of userspace is better.
Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Anton Ivanov <aivanov@brocade.com>
[rw: massaged commit message]
Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um/os-Linux/main.c')
| -rw-r--r-- | arch/um/os-Linux/main.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c index df9191acd926..9d499de87e63 100644 --- a/arch/um/os-Linux/main.c +++ b/arch/um/os-Linux/main.c @@ -1,4 +1,5 @@ /* + * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de) * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) * Licensed under the GPL */ @@ -163,13 +164,13 @@ int __init main(int argc, char **argv, char **envp) /* * This signal stuff used to be in the reboot case. However, - * sometimes a SIGVTALRM can come in when we're halting (reproducably + * sometimes a timer signal can come in when we're halting (reproducably * when writing out gcov information, presumably because that takes * some time) and cause a segfault. */ - /* stop timers and set SIGVTALRM to be ignored */ - disable_timer(); + /* stop timers and set timer signal to be ignored */ + os_timer_disable(); /* disable SIGIO for the fds and set SIGIO to be ignored */ err = deactivate_all_fds(); |