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| author | Tejun Heo <tj@kernel.org> | 2013-11-29 15:42:58 (GMT) |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2013-11-29 15:42:58 (GMT) |
| commit | ac1e69aa78e2e799a8d5475595ba744bdf29b597 (patch) | |
| tree | 5a33e778c533270e44b6243337d8b49f83b37555 /kernel/cgroup.c | |
| parent | c729b11edf7458a939556e1889446184f42f37a7 (diff) | |
| download | linux-ac1e69aa78e2e799a8d5475595ba744bdf29b597.tar.xz | |
cgroup: don't skip seq_open on write only opens on pidlist files
Currently, cgroup_pidlist_open() skips seq_open() and pidlist loading
if the file is opened write-only, which is a sensible optimization as
pidlist loading can be costly and there often are occasions where
tasks or cgroup.procs is opened write-only. However, pidlist init and
release are planned to be moved to cgroup_pidlist_start/stop()
respectively which would make this optimization unnecessary.
This patch removes the optimization and always fully initializes
pidlist files regardless of open mode. This will help moving pidlist
handling to start/stop by unifying rw paths and removes the need for
specifying cftype->release() in addition to .release in
cgroup_pidlist_operations as file->f_op is now always overridden. As
pidlist files were the only user of cftype->release(), the next patch
will remove the method.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 13 |
1 files changed, 1 insertions, 12 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 34fd1be..1e09ded 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -3781,12 +3781,7 @@ static void cgroup_release_pid_array(struct cgroup_pidlist *l) static int cgroup_pidlist_release(struct inode *inode, struct file *file) { struct cgroup_pidlist *l; - if (!(file->f_mode & FMODE_READ)) - return 0; - /* - * the seq_file will only be initialized if the file was opened for - * reading; hence we check if it's not null only in that case. - */ + l = ((struct seq_file *)file->private_data)->private; cgroup_release_pid_array(l); return seq_release(inode, file); @@ -3811,10 +3806,6 @@ static int cgroup_pidlist_open(struct file *file, enum cgroup_filetype type) struct cgroup_pidlist *l; int retval; - /* Nothing to do for write-only files */ - if (!(file->f_mode & FMODE_READ)) - return 0; - /* have the array populated */ retval = pidlist_array_load(cgrp, type, &l); if (retval) @@ -3894,7 +3885,6 @@ static struct cftype cgroup_base_files[] = { .name = "cgroup.procs", .open = cgroup_procs_open, .write_u64 = cgroup_procs_write, - .release = cgroup_pidlist_release, .mode = S_IRUGO | S_IWUSR, }, { @@ -3919,7 +3909,6 @@ static struct cftype cgroup_base_files[] = { .flags = CFTYPE_INSANE, /* use "procs" instead */ .open = cgroup_tasks_open, .write_u64 = cgroup_tasks_write, - .release = cgroup_pidlist_release, .mode = S_IRUGO | S_IWUSR, }, { |