On Tue, Mar 13, 2012 at 11:34:46AM +0100, Florian Schmaus wrote: > From: Andor Daam <[email protected]> > > This patch makes dynamic enabling/disabling of zcache via a sysfsnode > possible.
There should be an patch to the Documentation/ABI/testing for these parameters. > The node is used to toggle the preexisting zcache_freeze variable to > stop/start accepting pages by zcache. What is the reasoning to do this in the frontend instead of the backend (Cleancache/frontswap)? > > Signed-off-by: Andor Daam <[email protected]> > Signed-off-by: Florian Schmaus <[email protected]> > Signed-off-by: Stefan Hengelein <[email protected]> > --- > drivers/staging/zcache/zcache-main.c | 57 > +++++++++++++++++++++++++++++----- > 1 files changed, 49 insertions(+), 8 deletions(-) > > diff --git a/drivers/staging/zcache/zcache-main.c > b/drivers/staging/zcache/zcache-main.c > index 2734dac..1bece03 100644 > --- a/drivers/staging/zcache/zcache-main.c > +++ b/drivers/staging/zcache/zcache-main.c > @@ -469,6 +469,15 @@ out: > } > > /* > + * When zcache is disabled ("frozen"), pools can be created and destroyed, > + * but all puts (and thus all other operations that require memory > allocation) > + * must fail. If zcache is unfrozen, accepts puts, then frozen again, > + * data consistency requires all puts while frozen to be converted into > + * flushes. > + */ > +static bool zcache_freeze; > + > +/* > * The following routines handle shrinking of ephemeral pages by evicting > * pages "least valuable" first. > */ > @@ -913,6 +922,45 @@ static struct kobj_attribute > zcache_zv_page_count_policy_percent_attr = { > .show = zv_page_count_policy_percent_show, > .store = zv_page_count_policy_percent_store, > }; > + > +static ssize_t zcache_freeze_show(struct kobject *kobj, > + struct kobj_attribute *attr, > + char *buf) > +{ > + if (zcache_freeze) > + return sprintf(buf, "1\n"); > + else > + return sprintf(buf, "0\n"); > +} > + > +static ssize_t zcache_freeze_store(struct kobject *kobj, > + struct kobj_attribute *attr, > + const char *buf, size_t count) > +{ > + unsigned int val; > + int err; > + > + if (!capable(CAP_SYS_ADMIN)) > + return -EPERM; > + > + err = kstrtouint(buf, 10, &val); > + if (err) > + return -EINVAL; > + > + if (val > 0) > + zcache_freeze = true; > + else > + zcache_freeze = false; > + > + return count; > +} > + > +static struct kobj_attribute zcache_freeze_attr = { > + .attr = { .name = "zcache_freeze", .mode = 0644 }, > + .show = zcache_freeze_show, > + .store = zcache_freeze_store, > +}; > + > #endif > > /* > @@ -1515,6 +1563,7 @@ static struct attribute *zcache_attrs[] = { > &zcache_zv_max_zsize_attr.attr, > &zcache_zv_max_mean_zsize_attr.attr, > &zcache_zv_page_count_policy_percent_attr.attr, > + &zcache_freeze_attr.attr, > NULL, > }; > > @@ -1524,14 +1573,6 @@ static struct attribute_group zcache_attr_group = { > }; > > #endif /* CONFIG_SYSFS */ > -/* > - * When zcache is disabled ("frozen"), pools can be created and destroyed, > - * but all puts (and thus all other operations that require memory > allocation) > - * must fail. If zcache is unfrozen, accepts puts, then frozen again, > - * data consistency requires all puts while frozen to be converted into > - * flushes. > - */ > -static bool zcache_freeze; > > /* > * zcache shrinker interface (only useful for ephemeral pages, so zbud only) > -- > 1.7.5.4 _______________________________________________ devel mailing list [email protected] http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
