From 171cef6d6ec6c1b4e95f2053545b2dd91931518b Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Wed, 8 Feb 2017 10:44:13 +1100 Subject: 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 Acked-by: Michal Hocko Acked-by: Peter Zijlstra (Intel) Acked-by: David Rientjes Signed-off-by: Andrew Morton --- include/linux/mm_types.h | 23 +++++++++++++++++++++-- 1 file 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 */ -- cgit v1.2.3