Messages in this thread Patch in this message | | | Date | Mon, 25 Feb 2008 10:54:20 -0800 | From | Paul Menage <> | Subject | Re: [PATCH] Memory Resource Controller Add Boot Option |
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>> 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 - 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.
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
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