On Mon, 26 Oct 2009 08:15:29 -0700
Matt Helsley <matthltc@xxxxxxxxxx> wrote:
> cgroup subsystems may find the O_APPEND and O_NONBLOCK flags useful
> in determining the way they handle writes. For now only pass these
> flags through the write_string op.
>
> A subsequent patch will make use of the O_NONBLOCK flag in the
> cgroup freezer write_string op.
>
> Signed-off-by: Matt Helsley <matthltc@xxxxxxxxxx>
> Cc: Nathan Lynch <ntl@xxxxxxxxx>
> Cc: Paul Menage <menage@xxxxxxxxxx>
> Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
>
> (Cc'ing mem controller maintainers in case they find this useful..)
> Cc: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
> Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Hmm, maybe useful if we decided to add memory.drop_memory or some...
But now, we have no plan to add backup thread(for asynchronous job).
or some trylock ops.
Anyway, no objection from me if you want this.
-Kame
> ---
> include/linux/cgroup.h | 3 ++-
> kernel/cgroup.c | 5 +++--
> kernel/cgroup_freezer.c | 5 ++---
> kernel/cpuset.c | 2 +-
> mm/memcontrol.c | 2 +-
> security/device_cgroup.c | 2 +-
> 6 files changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
> index 90bba9e..627da35 100644
> --- a/include/linux/cgroup.h
> +++ b/include/linux/cgroup.h
> @@ -315,8 +315,9 @@ struct cftype {
> * buffer of maximum length determined by max_write_len.
> * Returns 0 or -ve error code.
> */
> +#define CFTYPE_F_FLAGS (O_APPEND|O_NONBLOCK)
> int (*write_string)(struct cgroup *cgrp, struct cftype *cft,
> - const char *buffer);
> + unsigned int f_flags, const char *buffer);
> /*
> * trigger() callback can be used to get some kick from the
> * userspace, when the actual string written is not important
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index b6eadfe..af07d05 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -1449,7 +1449,7 @@ bool cgroup_lock_live_group(struct cgroup *cgrp)
> }
>
> static int cgroup_release_agent_write(struct cgroup *cgrp, struct cftype *cft,
> - const char *buffer)
> + unsigned int f_flags, const char *buffer)
> {
> BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
> if (!cgroup_lock_live_group(cgrp))
> @@ -1534,7 +1534,8 @@ static ssize_t cgroup_write_string(struct cgroup *cgrp, struct cftype *cft,
>
> buffer[nbytes] = 0; /* nul-terminate */
> strstrip(buffer);
> - retval = cft->write_string(cgrp, cft, buffer);
> + retval = cft->write_string(cgrp, cft, file->f_flags & CFTYPE_F_FLAGS,
> + buffer);
> if (!retval)
> retval = nbytes;
> out:
> diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
> index 7925850..c97680f 100644
> --- a/kernel/cgroup_freezer.c
> +++ b/kernel/cgroup_freezer.c
> @@ -343,9 +343,8 @@ out:
> return retval;
> }
>
> -static int freezer_write(struct cgroup *cgroup,
> - struct cftype *cft,
> - const char *buffer)
> +static int freezer_write(struct cgroup *cgroup, struct cftype *cft,
> + unsigned int f_flags, const char *buffer)
> {
> int retval;
> enum freezer_state goal_state;
> diff --git a/kernel/cpuset.c b/kernel/cpuset.c
> index 7e75a41..de7f397 100644
> --- a/kernel/cpuset.c
> +++ b/kernel/cpuset.c
> @@ -1470,7 +1470,7 @@ static int cpuset_write_s64(struct cgroup *cgrp, struct cftype *cft, s64 val)
> * Common handling for a write to a "cpus" or "mems" file.
> */
> static int cpuset_write_resmask(struct cgroup *cgrp, struct cftype *cft,
> - const char *buf)
> + unsigned int f_flags, const char *buf)
> {
> int retval = 0;
> struct cpuset *cs = cgroup_cs(cgrp);
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index fd4529d..fd9c737 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2072,7 +2072,7 @@ static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
> * RES_LIMIT.
> */
> static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
> - const char *buffer)
> + unsigned int f_flags, const char *buffer)
> {
> struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
> int type, name;
> diff --git a/security/device_cgroup.c b/security/device_cgroup.c
> index b8186ba..65d32ce 100644
> --- a/security/device_cgroup.c
> +++ b/security/device_cgroup.c
> @@ -428,7 +428,7 @@ handle:
> }
>
> static int devcgroup_access_write(struct cgroup *cgrp, struct cftype *cft,
> - const char *buffer)
> + unsigned int f_flags, const char *buffer)
> {
> int retval;
>
> --
> 1.5.6.3
>
>
>
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