lkml.org 
[lkml]   [2009]   [Jan]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: [PATCH 2/4] cgroup:add css_is_populated
    Li-san, If you don't like this, could you give me an idea for
    "How to check cgroup is fully ready or not" ?

    BTW, why "we have a half filled direcotory - oh well" is allowed....

    Thanks,
    -Kame



    On Thu, 15 Jan 2009 19:27:12 +0900
    KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:

    > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
    >
    > cgroup creation is done in several stages.
    > After allocated and linked to cgroup's hierarchy tree, all necessary
    > control files are created.
    >
    > When using CSS_ID, scanning cgroups without cgrouo_lock(), status
    > of cgroup is important. At removal of cgroup/css, css_tryget() works fine
    > and we can write a safe code. At creation, we need some flag to show
    > "This cgroup is not ready yet"
    >
    > This patch adds CSS_POPULATED flag.
    >
    > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
    >
    > ---
    > Index: mmotm-2.6.29-Jan14/include/linux/cgroup.h
    > ===================================================================
    > --- mmotm-2.6.29-Jan14.orig/include/linux/cgroup.h
    > +++ mmotm-2.6.29-Jan14/include/linux/cgroup.h
    > @@ -69,6 +69,7 @@ struct cgroup_subsys_state {
    > enum {
    > CSS_ROOT, /* This CSS is the root of the subsystem */
    > CSS_REMOVED, /* This CSS is dead */
    > + CSS_POPULATED, /* This CSS finished all initialization */
    > };
    >
    > /*
    > @@ -90,6 +91,11 @@ static inline bool css_is_removed(struct
    > return test_bit(CSS_REMOVED, &css->flags);
    > }
    >
    > +static inline bool css_is_populated(struct cgroup_subsys_state *css)
    > +{
    > + return test_bit(CSS_POPULATED, &css->flags);
    > +}
    > +
    > /*
    > * Call css_tryget() to take a reference on a css if your existing
    > * (known-valid) reference isn't already ref-counted. Returns false if
    > Index: mmotm-2.6.29-Jan14/kernel/cgroup.c
    > ===================================================================
    > --- mmotm-2.6.29-Jan14.orig/kernel/cgroup.c
    > +++ mmotm-2.6.29-Jan14/kernel/cgroup.c
    > @@ -2326,8 +2326,10 @@ static int cgroup_populate_dir(struct cg
    > }
    >
    > for_each_subsys(cgrp->root, ss) {
    > + struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id];
    > if (ss->populate && (err = ss->populate(ss, cgrp)) < 0)
    > return err;
    > + set_bit(CSS_POPULATED, &css->flags);
    > }
    >
    > return 0;
    >
    > --
    > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    > the body of a message to majordomo@vger.kernel.org
    > More majordomo info at http://vger.kernel.org/majordomo-info.html
    > Please read the FAQ at http://www.tux.org/lkml/
    >



    \
     
     \ /
      Last update: 2009-01-16 04:03    [W:0.048 / U:90.132 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site