| Message ID | 20160125164930.9670.46763.stgit@warthog.procyon.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 01/25/2016 11:49 AM, David Howells wrote: > From: NeilBrown <neilb@suse.de> > > When cachefilesd finds that it needs to cull, but that culling doesn't > achieve anything, it sets an alarm to wake it in 30 seconds to try again. > But as read_cache_state() will detect that culling is still needed, it will > immediately try again anyway. > > This results in 100% cpu usage of no value. > > This patch causes culling to be blocked until the 30 second alarm goes off. > > It also changes the test to decide whether to enter poll() after blocking > signals to test exactly those values that might be changed by a signal. > Testing these is important, testing anything else is pointless. > > Signed-off-by: NeilBrown <neilb@suse.de> > Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Steve Dickson <steved@redhat.com> steved. > --- > > cachefilesd.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/cachefilesd.c b/cachefilesd.c > index 6658ba5..eaa1bb0 100644 > --- a/cachefilesd.c > +++ b/cachefilesd.c > @@ -99,6 +99,7 @@ static struct object **cullready; > static unsigned nr_in_build_table; > static unsigned nr_in_ready_table; > static int ncullable; > +static bool cull_delayed; > > > static const char *configfile = "/etc/cachefilesd.conf"; > @@ -246,6 +247,7 @@ static void sigio(int sig) > static void sigalrm(int sig) > { > jumpstart_scan = true; > + cull_delayed = false; > } > > /*****************************************************************************/ > @@ -613,11 +615,11 @@ static void cachefilesd(void) > > /* sleep without racing on reap and cull with the signal > * handlers */ > - if (!scan && !reap && !cull) { > + if (!scan && !reap && !(cull && !cull_delayed)) { > if (sigprocmask(SIG_BLOCK, &sigs, &osigs) < 0) > oserror("Unable to block signals"); > > - if (!reap && !cull) { > + if (!reap && !stop && !jumpstart_scan) { > if (ppoll(pollfds, 1, NULL, &osigs) < 0 && > errno != EINTR) > oserror("Unable to suspend process"); > @@ -644,7 +646,7 @@ static void cachefilesd(void) > if (cull) { > if (nr_in_ready_table > 0) > cull_objects(); > - else if (nr_in_build_table == 0) > + else if (nr_in_build_table == 0 && !cull_delayed) > jumpstart_scan = true; > } > > @@ -1364,6 +1366,7 @@ static void decant_cull_table(void) > > /* if nothing there, scan again in a short while */ > if (nr_in_build_table == 0) { > + cull_delayed = true; > signal(SIGALRM, sigalrm); > alarm(30); > return; > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 01/25/2016 11:49 AM, David Howells wrote: > From: NeilBrown <neilb@suse.de> > > When cachefilesd finds that it needs to cull, but that culling doesn't > achieve anything, it sets an alarm to wake it in 30 seconds to try again. > But as read_cache_state() will detect that culling is still needed, it will > immediately try again anyway. > > This results in 100% cpu usage of no value. > > This patch causes culling to be blocked until the 30 second alarm goes off. > > It also changes the test to decide whether to enter poll() after blocking > signals to test exactly those values that might be changed by a signal. > Testing these is important, testing anything else is pointless. > > Signed-off-by: NeilBrown <neilb@suse.de> > Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> > --- > > cachefilesd.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/cachefilesd.c b/cachefilesd.c > index 6658ba5..eaa1bb0 100644 > --- a/cachefilesd.c > +++ b/cachefilesd.c > @@ -99,6 +99,7 @@ static struct object **cullready; > static unsigned nr_in_build_table; > static unsigned nr_in_ready_table; > static int ncullable; > +static bool cull_delayed; > > > static const char *configfile = "/etc/cachefilesd.conf"; > @@ -246,6 +247,7 @@ static void sigio(int sig) > static void sigalrm(int sig) > { > jumpstart_scan = true; > + cull_delayed = false; > } > > /*****************************************************************************/ > @@ -613,11 +615,11 @@ static void cachefilesd(void) > > /* sleep without racing on reap and cull with the signal > * handlers */ > - if (!scan && !reap && !cull) { > + if (!scan && !reap && !(cull && !cull_delayed)) { > if (sigprocmask(SIG_BLOCK, &sigs, &osigs) < 0) > oserror("Unable to block signals"); > > - if (!reap && !cull) { > + if (!reap && !stop && !jumpstart_scan) { > if (ppoll(pollfds, 1, NULL, &osigs) < 0 && > errno != EINTR) > oserror("Unable to suspend process"); > @@ -644,7 +646,7 @@ static void cachefilesd(void) > if (cull) { > if (nr_in_ready_table > 0) > cull_objects(); > - else if (nr_in_build_table == 0) > + else if (nr_in_build_table == 0 && !cull_delayed) > jumpstart_scan = true; > } > > @@ -1364,6 +1366,7 @@ static void decant_cull_table(void) > > /* if nothing there, scan again in a short while */ > if (nr_in_build_table == 0) { > + cull_delayed = true; > signal(SIGALRM, sigalrm); > alarm(30); > return; > > -- > Linux-cachefs mailing list > Linux-cachefs@redhat.com > https://www.redhat.com/mailman/listinfo/linux-cachefs >
diff --git a/cachefilesd.c b/cachefilesd.c index 6658ba5..eaa1bb0 100644 --- a/cachefilesd.c +++ b/cachefilesd.c @@ -99,6 +99,7 @@ static struct object **cullready; static unsigned nr_in_build_table; static unsigned nr_in_ready_table; static int ncullable; +static bool cull_delayed; static const char *configfile = "/etc/cachefilesd.conf"; @@ -246,6 +247,7 @@ static void sigio(int sig) static void sigalrm(int sig) { jumpstart_scan = true; + cull_delayed = false; } /*****************************************************************************/ @@ -613,11 +615,11 @@ static void cachefilesd(void) /* sleep without racing on reap and cull with the signal * handlers */ - if (!scan && !reap && !cull) { + if (!scan && !reap && !(cull && !cull_delayed)) { if (sigprocmask(SIG_BLOCK, &sigs, &osigs) < 0) oserror("Unable to block signals"); - if (!reap && !cull) { + if (!reap && !stop && !jumpstart_scan) { if (ppoll(pollfds, 1, NULL, &osigs) < 0 && errno != EINTR) oserror("Unable to suspend process"); @@ -644,7 +646,7 @@ static void cachefilesd(void) if (cull) { if (nr_in_ready_table > 0) cull_objects(); - else if (nr_in_build_table == 0) + else if (nr_in_build_table == 0 && !cull_delayed) jumpstart_scan = true; } @@ -1364,6 +1366,7 @@ static void decant_cull_table(void) /* if nothing there, scan again in a short while */ if (nr_in_build_table == 0) { + cull_delayed = true; signal(SIGALRM, sigalrm); alarm(30); return;