Messages in this thread | | | Date | Fri, 07 Mar 2008 09:13:46 +0900 | From | Li Zefan <> | Subject | Re: [PATCH] Add cgroup support for enabling controllers at boot time |
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Balbir Singh wrote: > From: Paul Menage <menage@google.com> > > The effects of cgroup_disable=foo are: > > - foo doesn't show up in /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 > > 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. > > [Balbir added Documentation/kernel-parameters updates] > > Signed-off-by: Paul Menage <menage@google.com> > Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> > --- > > Documentation/kernel-parameters.txt | 4 ++++ > include/linux/cgroup.h | 1 + > kernel/cgroup.c | 27 +++++++++++++++++++++++++-- > 3 files changed, 30 insertions(+), 2 deletions(-) > > diff -puN include/linux/cgroup.h~cgroup_disable include/linux/cgroup.h > --- linux-2.6.25-rc4/include/linux/cgroup.h~cgroup_disable 2008-03-06 12:19:38.000000000 +0530 > +++ linux-2.6.25-rc4-balbir/include/linux/cgroup.h 2008-03-06 12:19:38.000000000 +0530 > @@ -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; > diff -puN kernel/cgroup.c~cgroup_disable kernel/cgroup.c > --- linux-2.6.25-rc4/kernel/cgroup.c~cgroup_disable 2008-03-06 12:19:38.000000000 +0530 > +++ linux-2.6.25-rc4-balbir/kernel/cgroup.c 2008-03-06 12:19:38.000000000 +0530 > @@ -782,7 +782,14 @@ 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)) { > @@ -800,7 +807,8 @@ 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; > } > } > @@ -2604,6 +2612,8 @@ 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); > @@ -3010,3 +3020,16 @@ 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); > diff -puN Documentation/kernel-parameters.txt~cgroup_disable Documentation/kernel-parameters.txt > --- linux-2.6.25-rc4/Documentation/kernel-parameters.txt~cgroup_disable 2008-03-06 17:57:32.000000000 +0530 > +++ linux-2.6.25-rc4-balbir/Documentation/kernel-parameters.txt 2008-03-06 18:00:32.000000000 +0530 > @@ -383,6 +383,10 @@ and is between 256 and 4096 characters. > ccw_timeout_log [S390] > See Documentation/s390/CommonIO for details. > > + cgroup_disable= [KNL] Enable disable a particular controller > + Format: {name of the controller} > + See /proc/cgroups for a list of compiled controllers > +
The changelog of this patch: - foo doesn't show up in /proc/cgroups
So a disabled subsystem won't show up in /proc/cgroups. In a previous mail, I asked whether it will be useful to print out the disable bit in /proc/cgroups, so we can distinguish a subsystem from disaled and not-compiled.
> checkreqprot [SELINUX] Set initial checkreqprot flag value. > Format: { "0" | "1" } > See security/selinux/Kconfig help text. > _ >
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