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authorRafael J. Wysocki <rjw@sisk.pl>2007-07-17 04:03:35 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-17 10:23:02 -0700
commit831441862956fffa17b9801db37e6ea1650b0f69 (patch)
treeb0334921341f8f1734bdd3243de76d676329d21c /init
parent787d2214c19bcc9b6ac48af0ce098277a801eded (diff)
downloadlinux-831441862956fffa17b9801db37e6ea1650b0f69.tar.gz
Freezer: make kernel threads nonfreezable by default
Currently, the freezer treats all tasks as freezable, except for the kernel threads that explicitly set the PF_NOFREEZE flag for themselves. This approach is problematic, since it requires every kernel thread to either set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't care for the freezing of tasks at all. It seems better to only require the kernel threads that want to or need to be frozen to use some freezer-related code and to remove any freezer-related code from the other (nonfreezable) kernel threads, which is done in this patch. The patch causes all kernel threads to be nonfreezable by default (ie. to have PF_NOFREEZE set by default) and introduces the set_freezable() function that should be called by the freezable kernel threads in order to unset PF_NOFREEZE. It also makes all of the currently freezable kernel threads call set_freezable(), so it shouldn't cause any (intentional) change of behaviour to appear. Additionally, it updates documentation to describe the freezing of tasks more accurately. [akpm@linux-foundation.org: build fixes] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net> Cc: Pavel Machek <pavel@ucw.cz> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'init')
-rw-r--r--init/do_mounts_initrd.c7
1 files changed, 2 insertions, 5 deletions
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index b222ce9e1c8..a6b4c0c08e1 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -56,12 +56,9 @@ static void __init handle_initrd(void)
sys_chroot(".");
pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);
- if (pid > 0) {
- while (pid != sys_wait4(-1, NULL, 0, NULL)) {
- try_to_freeze();
+ if (pid > 0)
+ while (pid != sys_wait4(-1, NULL, 0, NULL))
yield();
- }
- }
/* move initrd to rootfs' /old */
sys_fchdir(old_fd);