diff options
Diffstat (limited to 'mm/mempolicy.c')
| -rw-r--r-- | mm/mempolicy.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index e93cc740c22b..4f71cfd29c6f 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -422,6 +422,37 @@ static int contextualize_policy(int mode, nodemask_t *nodes) return mpol_check_policy(mode, nodes); } + +/* + * Update task->flags PF_MEMPOLICY bit: set iff non-default + * mempolicy. Allows more rapid checking of this (combined perhaps + * with other PF_* flag bits) on memory allocation hot code paths. + * + * If called from outside this file, the task 'p' should -only- be + * a newly forked child not yet visible on the task list, because + * manipulating the task flags of a visible task is not safe. + * + * The above limitation is why this routine has the funny name + * mpol_fix_fork_child_flag(). + * + * It is also safe to call this with a task pointer of current, + * which the static wrapper mpol_set_task_struct_flag() does, + * for use within this file. + */ + +void mpol_fix_fork_child_flag(struct task_struct *p) +{ + if (p->mempolicy) + p->flags |= PF_MEMPOLICY; + else + p->flags &= ~PF_MEMPOLICY; +} + +static void mpol_set_task_struct_flag(void) +{ + mpol_fix_fork_child_flag(current); +} + /* Set the process memory policy */ long do_set_mempolicy(int mode, nodemask_t *nodes) { @@ -434,6 +465,7 @@ long do_set_mempolicy(int mode, nodemask_t *nodes) return PTR_ERR(new); mpol_free(current->mempolicy); current->mempolicy = new; + mpol_set_task_struct_flag(); if (new && new->policy == MPOL_INTERLEAVE) current->il_next = first_node(new->v.nodes); return 0; |