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Date: Wed, 18 Jan 2012 15:59:57 +0800
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Subject: Re: [PATCH 1/2] cgroup: revise how we re-populate root directory
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>> @@ -1284,6 +1296,7 @@ static int cgroup_remount(struct super_block *sb, int *flags, char *data)
>>        struct cgroupfs_root *root = sb->s_fs_info;
>>        struct cgroup *cgrp = &root->top_cgroup;
>>        struct cgroup_sb_opts opts;
>> +       unsigned long added_bits, removed_bits;
>>
>>        mutex_lock(&cgrp->dentry->d_inode->i_mutex);
>>        mutex_lock(&cgroup_mutex);
>> @@ -1294,6 +1307,9 @@ static int cgroup_remount(struct super_block *sb, int *flags, char *data)
>>        if (ret)
>>                goto out_unlock;
>>
>> +       added_bits = opts.subsys_bits & ~root->subsys_bits;
>> +       removed_bits = root->subsys_bits & ~opts.subsys_bits;
>> +
> 
> Should it be the following？：
>           added_bits = opts.subsys_bits & ~root->actual_subsys_bits;
>           removed_bits = root->actual_subsys_bits & ~opts.subsys_bits;
> 

subsys_bits and actual_subsys_bits differ during cgroup_mount() only,
and in other places they are replaceable with each other.

Thanks for looking into this.