tuna: fix the check of PF_NO_SETAFFINITY flag for threads
Tuna checks if PF_NO_SETAFFINITY is set on /proc/PID/stat's 'flag' field
to verify if it is possible to migrate a process/thread. This is
working fine for process, but not for threads.
For threads, the file /proc/TID/stat is being checked, but this file
does not exist as the stat file of a thread is at
/proc/PID/task/TID/stat. Hence, the check was failing and threads were
not being migrated.
This patch adds a function to check thread's stat file, and this
function is called to verify the PF_NO_SETAFFINITY flag for threads.
Committer note:
Before, doing:
# tuna --cpu 3 --isolate
# tuna -t firefox -CP
thread ctxt_switches
pid SCHED_ rtpri affinity voluntary nonvoluntary cmd
14838 OTHER 0 0,1,2 873954 27498 firefox
14857 OTHER 0 0,1,2,3 3 1 Gecko_IOThread
14858 OTHER 0 0,1,2,3 1 0 Link Monitor
14859 OTHER 0 0,1,2,3 126717 12214 Socket Thread
<SNIP>
So it affected just the main thread, all the children remained with
their existing affinity mask.
After the patch:
# tuna --cpu 3 --isolate
# tuna -t firefox -CP
thread ctxt_switches
pid SCHED_ rtpri affinity voluntary nonvoluntary cmd
14838 OTHER 0 0,1,2 877488 27583 firefox
14857 OTHER 0 0,1,2 3 1 Gecko_IOThread
14858 OTHER 0 0,1,2 1 0 Link Monitor
14859 OTHER 0 0,1,2 126933 12235 Socket Thread
<SNIP>
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Kastner <jkastner@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Tuna <tuna-devel@lists.fedorahosted.org>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1286221
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
1 file changed
