diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup.c | 39 | ||||
| -rw-r--r-- | kernel/cpuset.c | 9 | ||||
| -rw-r--r-- | kernel/sys.c | 2 | ||||
| -rw-r--r-- | kernel/utsname_sysctl.c | 23 |
4 files changed, 52 insertions, 21 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 453100a..d9d5648 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2027,7 +2027,7 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader) goto out_free_group_list; /* prevent changes to the threadgroup list while we take a snapshot. */ - rcu_read_lock(); + read_lock(&tasklist_lock); if (!thread_group_leader(leader)) { /* * a race with de_thread from another thread's exec() may strip @@ -2036,7 +2036,7 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader) * throw this task away and try again (from cgroup_procs_write); * this is "double-double-toil-and-trouble-check locking". */ - rcu_read_unlock(); + read_unlock(&tasklist_lock); retval = -EAGAIN; goto out_free_group_list; } @@ -2057,7 +2057,7 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader) } while_each_thread(leader, tsk); /* remember the number of threads in the array for later. */ group_size = i; - rcu_read_unlock(); + read_unlock(&tasklist_lock); /* * step 1: check that we can legitimately attach to the cgroup. @@ -2135,14 +2135,17 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader) oldcgrp = task_cgroup_from_root(tsk, root); if (cgrp == oldcgrp) continue; - /* attach each task to each subsystem */ - for_each_subsys(root, ss) { - if (ss->attach_task) - ss->attach_task(cgrp, tsk); - } /* if the thread is PF_EXITING, it can just get skipped. */ retval = cgroup_task_migrate(cgrp, oldcgrp, tsk, true); - BUG_ON(retval != 0 && retval != -ESRCH); + if (retval == 0) { + /* attach each task to each subsystem */ + for_each_subsys(root, ss) { + if (ss->attach_task) + ss->attach_task(cgrp, tsk); + } + } else { + BUG_ON(retval != -ESRCH); + } } /* nothing is sensitive to fork() after this point. */ @@ -4880,9 +4883,9 @@ void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css) rcu_assign_pointer(id->css, NULL); rcu_assign_pointer(css->id, NULL); - spin_lock(&ss->id_lock); + write_lock(&ss->id_lock); idr_remove(&ss->idr, id->id); - spin_unlock(&ss->id_lock); + write_unlock(&ss->id_lock); kfree_rcu(id, rcu_head); } EXPORT_SYMBOL_GPL(free_css_id); @@ -4908,10 +4911,10 @@ static struct css_id *get_new_cssid(struct cgroup_subsys *ss, int depth) error = -ENOMEM; goto err_out; } - spin_lock(&ss->id_lock); + write_lock(&ss->id_lock); /* Don't use 0. allocates an ID of 1-65535 */ error = idr_get_new_above(&ss->idr, newid, 1, &myid); - spin_unlock(&ss->id_lock); + write_unlock(&ss->id_lock); /* Returns error when there are no free spaces for new ID.*/ if (error) { @@ -4926,9 +4929,9 @@ static struct css_id *get_new_cssid(struct cgroup_subsys *ss, int depth) return newid; remove_idr: error = -ENOSPC; - spin_lock(&ss->id_lock); + write_lock(&ss->id_lock); idr_remove(&ss->idr, myid); - spin_unlock(&ss->id_lock); + write_unlock(&ss->id_lock); err_out: kfree(newid); return ERR_PTR(error); @@ -4940,7 +4943,7 @@ static int __init_or_module cgroup_init_idr(struct cgroup_subsys *ss, { struct css_id *newid; - spin_lock_init(&ss->id_lock); + rwlock_init(&ss->id_lock); idr_init(&ss->idr); newid = get_new_cssid(ss, 0); @@ -5035,9 +5038,9 @@ css_get_next(struct cgroup_subsys *ss, int id, * scan next entry from bitmap(tree), tmpid is updated after * idr_get_next(). */ - spin_lock(&ss->id_lock); + read_lock(&ss->id_lock); tmp = idr_get_next(&ss->idr, &tmpid); - spin_unlock(&ss->id_lock); + read_unlock(&ss->id_lock); if (!tmp) break; diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 10131fd..ed0ff44 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -949,6 +949,8 @@ static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from, static void cpuset_change_task_nodemask(struct task_struct *tsk, nodemask_t *newmems) { + bool masks_disjoint = !nodes_intersects(*newmems, tsk->mems_allowed); + repeat: /* * Allow tasks that have access to memory reserves because they have @@ -963,7 +965,6 @@ repeat: nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems); mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1); - /* * ensure checking ->mems_allowed_change_disable after setting all new * allowed nodes. @@ -980,9 +981,11 @@ repeat: /* * Allocation of memory is very fast, we needn't sleep when waiting - * for the read-side. + * for the read-side. No wait is necessary, however, if at least one + * node remains unchanged. */ - while (ACCESS_ONCE(tsk->mems_allowed_change_disable)) { + while (masks_disjoint && + ACCESS_ONCE(tsk->mems_allowed_change_disable)) { task_unlock(tsk); if (!task_curr(tsk)) yield(); diff --git a/kernel/sys.c b/kernel/sys.c index 5845950..d06c091 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1286,6 +1286,7 @@ SYSCALL_DEFINE2(sethostname, char __user *, name, int, len) memset(u->nodename + len, 0, sizeof(u->nodename) - len); errno = 0; } + uts_proc_notify(UTS_PROC_HOSTNAME); up_write(&uts_sem); return errno; } @@ -1336,6 +1337,7 @@ SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len) memset(u->domainname + len, 0, sizeof(u->domainname) - len); errno = 0; } + uts_proc_notify(UTS_PROC_DOMAINNAME); up_write(&uts_sem); return errno; } diff --git a/kernel/utsname_sysctl.c b/kernel/utsname_sysctl.c index a2cd77e..3b0d48e 100644 --- a/kernel/utsname_sysctl.c +++ b/kernel/utsname_sysctl.c @@ -13,6 +13,7 @@ #include <linux/uts.h> #include <linux/utsname.h> #include <linux/sysctl.h> +#include <linux/wait.h> static void *get_uts(ctl_table *table, int write) { @@ -51,12 +52,19 @@ static int proc_do_uts_string(ctl_table *table, int write, uts_table.data = get_uts(table, write); r = proc_dostring(&uts_table,write,buffer,lenp, ppos); put_uts(table, write, uts_table.data); + + if (write) + proc_sys_poll_notify(table->poll); + return r; } #else #define proc_do_uts_string NULL #endif +static DEFINE_CTL_TABLE_POLL(hostname_poll); +static DEFINE_CTL_TABLE_POLL(domainname_poll); + static struct ctl_table uts_kern_table[] = { { .procname = "ostype", @@ -85,6 +93,7 @@ static struct ctl_table uts_kern_table[] = { .maxlen = sizeof(init_uts_ns.name.nodename), .mode = 0644, .proc_handler = proc_do_uts_string, + .poll = &hostname_poll, }, { .procname = "domainname", @@ -92,6 +101,7 @@ static struct ctl_table uts_kern_table[] = { .maxlen = sizeof(init_uts_ns.name.domainname), .mode = 0644, .proc_handler = proc_do_uts_string, + .poll = &domainname_poll, }, {} }; @@ -105,6 +115,19 @@ static struct ctl_table uts_root_table[] = { {} }; +#ifdef CONFIG_PROC_SYSCTL +/* + * Notify userspace about a change in a certain entry of uts_kern_table, + * identified by the parameter proc. + */ +void uts_proc_notify(enum uts_proc proc) +{ + struct ctl_table *table = &uts_kern_table[proc]; + + proc_sys_poll_notify(table->poll); +} +#endif + static int __init utsname_sysctl_init(void) { register_sysctl_table(uts_root_table); |
