Paul Menage wrote: >>> I'll send out a prototype for comment. > > Something like the patch below. The effects of cgroup_disable=foo are: > > - foo doesn't show up in /proc/cgroups
Or we can print out the disable flag, maybe this will be better? Because we can distinguish from disabled and not compiled in from /proc/cgroups. > - foo isn't auto-mounted if you mount all cgroups in a single hierarchy > - foo isn't visible as an individually mountable subsystem You mentioned in a previous mail if we mount a disabled subsystem we will get an error. Here we just ignore the mount option. Which makes more sense ? > > As a result there will only ever be one call to foo->create(), at init > time; all processes will stay in this group, and the group will never be > mounted on a visible hierarchy. Any additional effects (e.g. not > allocating metadata) are up to the foo subsystem. > > This doesn't handle early_init subsystems (their "disabled" bit isn't > set be, but it could easily be extended to do so if any of the > early_init systems wanted it - I think it would just involve some > nastier parameter processing since it would occur before the > command-line argument parser had been run. > > include/linux/cgroup.h | 1 + > kernel/cgroup.c | 29 +++++++++++++++++++++++++++-- > 2 files changed, 28 insertions(+), 2 deletions(-) > > Index: cgroup_disable-2.6.25-rc2-mm1/include/linux/cgroup.h > =================================================================== > --- cgroup_disable-2.6.25-rc2-mm1.orig/include/linux/cgroup.h > +++ cgroup_disable-2.6.25-rc2-mm1/include/linux/cgroup.h > @@ -256,6 +256,7 @@ struct cgroup_subsys { > void (*bind)(struct cgroup_subsys *ss, struct cgroup *root); > int subsys_id; > int active; > + int disabled; > int early_init; > #define MAX_CGROUP_TYPE_NAMELEN 32 > const char *name; > Index: cgroup_disable-2.6.25-rc2-mm1/kernel/cgroup.c > =================================================================== > --- cgroup_disable-2.6.25-rc2-mm1.orig/kernel/cgroup.c > +++ cgroup_disable-2.6.25-rc2-mm1/kernel/cgroup.c > @@ -790,7 +790,14 @@ static int parse_cgroupfs_options(char * > if (!*token) > return -EINVAL; > if (!strcmp(token, "all")) { > - opts->subsys_bits = (1 << CGROUP_SUBSYS_COUNT) - 1; > + /* Add all non-disabled subsystems */ > + int i; > + opts->subsys_bits = 0; > + for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { > + struct cgroup_subsys *ss = subsys[i]; > + if (!ss->disabled) > + opts->subsys_bits |= 1ul << i; > + } > } else if (!strcmp(token, "noprefix")) { > set_bit(ROOT_NOPREFIX, &opts->flags); > } else if (!strncmp(token, "release_agent=", 14)) { > @@ -808,7 +815,8 @@ static int parse_cgroupfs_options(char * > for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { > ss = subsys[i]; > if (!strcmp(token, ss->name)) { > - set_bit(i, &opts->subsys_bits); > + if (!ss->disabled) > + set_bit(i, &opts->subsys_bits); > break; > } > } > @@ -2596,6 +2606,8 @@ static int proc_cgroupstats_show(struct > mutex_lock(&cgroup_mutex); > for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { > struct cgroup_subsys *ss = subsys[i]; > + if (ss->disabled) > + continue; > seq_printf(m, "%s\t%lu\t%d\n", > ss->name, ss->root->subsys_bits, > ss->root->number_of_cgroups); > @@ -2991,3 +3003,16 @@ static void cgroup_release_agent(struct > spin_unlock(&release_list_lock); > mutex_unlock(&cgroup_mutex); > } > + > +static int __init cgroup_disable(char *str) > +{ > + int i; > + for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { > + struct cgroup_subsys *ss = subsys[i]; > + if (!strcmp(str, ss->name)) { > + ss->disabled = 1; > + break; > + } > + } > +} > +__setup("cgroup_disable=", cgroup_disable); > > >> >> Sure thing, if css has the flag, then it would nice. Could you wrap it >> up to say >> something like css_disabled(&mem_cgroup_subsys) >> >> > > It's the subsys object rather than the css (cgroup_subsys_state). > > We could have something like: > > #define cgroup_subsys_disabled(_ss) ((ss_)->disabled) > > but I don't see that > cgroup_subsys_disabled(&mem_cgroup_subsys) > is better than just putting > > mem_cgroup_subsys.disabled > > Paul > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/