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authorVegard Nossum <vegard.nossum@oracle.com>2017-02-27 14:30:16 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-27 18:43:48 -0800
commitb279ddc3382426f8e05068de3488a2993f68dc26 (patch)
treef1d5eb73fd31c7e34856e8d581e3a9a3f1ffa17d /include
parent388f79345502232d335467e8fa6f8e55a18844e1 (diff)
downloadlinux-b279ddc3382426f8e05068de3488a2993f68dc26.tar.bz2
mm: clarify mm_struct.mm_{users,count} documentation
Clarify documentation relating to mm_users and mm_count, and switch to kernel-doc syntax. Link: http://lkml.kernel.org/r/20161218123229.22952-4-vegard.nossum@oracle.com Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/mm_types.h23
1 files changed, 21 insertions, 2 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 808751d7b737..4f6d440ad785 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -407,8 +407,27 @@ struct mm_struct {
unsigned long task_size; /* size of task vm space */
unsigned long highest_vm_end; /* highest vma end address */
pgd_t * pgd;
- atomic_t mm_users; /* How many users with user space? */
- atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
+
+ /**
+ * @mm_users: The number of users including userspace.
+ *
+ * Use mmget()/mmget_not_zero()/mmput() to modify. When this drops
+ * to 0 (i.e. when the task exits and there are no other temporary
+ * reference holders), we also release a reference on @mm_count
+ * (which may then free the &struct mm_struct if @mm_count also
+ * drops to 0).
+ */
+ atomic_t mm_users;
+
+ /**
+ * @mm_count: The number of references to &struct mm_struct
+ * (@mm_users count as 1).
+ *
+ * Use mmgrab()/mmdrop() to modify. When this drops to 0, the
+ * &struct mm_struct is freed.
+ */
+ atomic_t mm_count;
+
atomic_long_t nr_ptes; /* PTE page table pages */
#if CONFIG_PGTABLE_LEVELS > 2
atomic_long_t nr_pmds; /* PMD page table pages */