[PATCH 14/38] Remove struct mm_struct::exe_file et al

Matt Helsley matthltc at us.ibm.com
Tue May 26 04:36:18 PDT 2009

I don't see any mention in the changelog of the point brought up by Ingo:


You also haven't responded to my comment about holding mmap


Also, please consider combining with Ingo's point with mine: the mmap
semaphore will be held for the duration of that long VMA walk. Plus
any userspace task can trigger that walk as often as they like via

It also appears you haven't responded to Eric and Andrew's suggestion
of a struct path in place of a file reference: 


Lastly, please keep me on Cc for future revisions of this patch since
I am interested in following changes to the implementation of

	-Matt Helsley

----- Forwarded message from Alexey Dobriyan <adobriyan at gmail.com> -----

From: Alexey Dobriyan <adobriyan at gmail.com>
To: akpm at linux-foundation.org
Subject: [PATCH 14/38] Remove struct mm_struct::exe_file et al
Date: Fri, 22 May 2009 08:55:08 +0400
Cc: xemul at parallels.com, containers at lists.linux-foundation.org,
        linux-kernel at vger.kernel.org, dave at linux.vnet.ibm.com,
        mingo at elte.hu, torvalds at linux-foundation.org,
        Alexey Dobriyan <adobriyan at gmail.com>

Commit 925d1c401fa6cfd0df5d2e37da8981494ccdec07 aka "procfs task exe
introduced struct mm_struct::exe_file and struct

The rationale is weak: unifying MMU and no-MMU version of /proc/*/exe
For this a) struct mm_struct becomes bigger, b) mmap/munmap/exit become
c) patch adds more code than removes in fact.

After commit 8feae13110d60cc6287afabc2887366b0eb226c2 aka
"NOMMU: Make VMAs per MM as for MMU-mode linux" no-MMU kernels also
maintain list of VMAs in ->mmap, so we can switch back for MMU version
of /proc/*/exe.

This also helps C/R, no need to save and restore ->exe_file and to count
additional references to check if there is a leak of struct file outside
group of checkpointed resources.

Signed-off-by: Alexey Dobriyan <adobriyan at gmail.com>
 fs/exec.c                |    2 -
 fs/proc/base.c           |  105
 include/linux/mm.h       |   12 -----
 include/linux/mm_types.h |    6 ---
 include/linux/proc_fs.h  |   20 ---------
 kernel/fork.c            |    3 -
 mm/mmap.c                |   22 ++--------
 mm/nommu.c               |   16 +------
 8 files changed, 36 insertions(+), 150 deletions(-)

More information about the Containers mailing list