mm/madvise.c: add description for MADV_WIPEONFORK and MADV_KEEPONFORK

mm/madvise.c has a brief description about all MADV_ flags.  Add a
description for the newly added MADV_WIPEONFORK and MADV_KEEPONFORK.

Although man page has the similar information, but it'd better to keep
the consistent with other flags.

Link: http://lkml.kernel.org/r/1506117328-88228-1-git-send-email-yang.s@alibaba-inc.com
Signed-off-by: Yang Shi <yang.s@alibaba-inc.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Yang Shi 2017-10-13 15:57:37 -07:00 committed by Linus Torvalds
parent cc3fa84045
commit c02c300932

View File

@ -757,6 +757,9 @@ madvise_behavior_valid(int behavior)
* MADV_DONTFORK - omit this area from child's address space when forking:
* typically, to avoid COWing pages pinned by get_user_pages().
* MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking.
* MADV_WIPEONFORK - present the child process with zero-filled memory in this
* range after a fork.
* MADV_KEEPONFORK - undo the effect of MADV_WIPEONFORK
* MADV_HWPOISON - trigger memory error handler as if the given memory range
* were corrupted by unrecoverable hardware memory failure.
* MADV_SOFT_OFFLINE - try to soft-offline the given range of memory.
@ -777,7 +780,9 @@ madvise_behavior_valid(int behavior)
* zero - success
* -EINVAL - start + len < 0, start is not page-aligned,
* "behavior" is not a valid value, or application
* is attempting to release locked or shared pages.
* is attempting to release locked or shared pages,
* or the specified address range includes file, Huge TLB,
* MAP_SHARED or VMPFNMAP range.
* -ENOMEM - addresses in the specified range are not currently
* mapped, or are outside the AS of the process.
* -EIO - an I/O error occurred while paging in data.