Messages in this thread Patch in this message | | | Date | Wed, 7 Dec 2011 02:53:15 +0400 | From | Cyrill Gorcunov <> | Subject | Re: [PATCH] fs, proc: Add start_data, end_data, start_brk members to /proc/$pid/stat v2 |
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On Wed, Dec 07, 2011 at 02:15:15AM +0400, Cyrill Gorcunov wrote: > On Tue, Dec 06, 2011 at 02:08:33PM -0800, Andrew Morton wrote: > > On Mon, 5 Dec 2011 22:20:11 +0400 > > Cyrill Gorcunov <gorcunov@openvz.org> wrote: > > > > > It helps to dump and restore this mm_struct members. > > > > Sorry, I'm not going to apply a patch with a changelog like that. > > > > OK, I'll update it. The problem is that while we "read" this entries > from procfs, the restoration is supposed to be done via prctl interface > (the patch is in fly, and I'm trying to improve it at moment). > > > It needs a full description of how this will be used and why it is > > needed. So that others can understand and evaluate the proposal, and > > any possible alternatives. > > > > Such a description would also let us see whether this is just some > > "hey, maybe we'll use this sometime" thing, in which case it should not > > yet be applied. > > I understand. > > > > > > fs/proc/array.c | 7 +++++-- > > > > Also, every change to any procfs interface should have an associated > > change to procfs documentation. If no relevant document exists then > > heck, write one. No exceptions. > > > > ok, thanks. > > Cyrill
What about such changelog? Does it look better?
Cyrill --- From: Cyrill Gorcunov <gorcunov@openvz.org> Subject: [PATCH] fs, proc: Add start_data, end_data, start_brk members to /proc/$pid/stat v3
These members are involved into calculation of program data segment size (which might be seen in /proc/<pid>/statm) and brk() call, so in a sake of restore we need these entries to be set to exactly same values a process had at dumpimg time.
While setting these entries back to a running task is supposed to be implemented via prctl interface (which is not addressed in this patch) the export of these values are done via /proc/$pid/stat, which btw already has start_code, end_code and start_stack entries.
v2: - Kees and Alexey pointed out that "1" hack is unnecessary, so make it to have plain (mm && permitted) ? mm->member : 0 form.
v3: - Andrew pointed that documentation update is missed. Chagelog is updated as well.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> CC: Alexey Dobriyan <adobriyan@gmail.com> --- Documentation/filesystems/proc.txt | 3 +++ fs/proc/array.c | 7 +++++-- 2 files changed, 8 insertions(+), 2 deletions(-)
Index: linux-2.6.git/Documentation/filesystems/proc.txt =================================================================== --- linux-2.6.git.orig/Documentation/filesystems/proc.txt +++ linux-2.6.git/Documentation/filesystems/proc.txt @@ -305,6 +305,9 @@ Table 1-4: Contents of the stat files (a blkio_ticks time spent waiting for block IO gtime guest time of the task in jiffies cgtime guest time of the task children in jiffies + start_data address above which program data is placed + end_data address above which program data is placed + start_brk address above which program data can be expanded with brk() call .............................................................................. The /proc/PID/maps file containing the currently mapped memory regions and Index: linux-2.6.git/fs/proc/array.c =================================================================== --- linux-2.6.git.orig/fs/proc/array.c +++ linux-2.6.git/fs/proc/array.c @@ -464,7 +464,7 @@ static int do_task_stat(struct seq_file seq_printf(m, "%d (%s) %c %d %d %d %d %d %u %lu \ %lu %lu %lu %lu %lu %ld %ld %ld %ld %d 0 %llu %lu %ld %lu %lu %lu %lu %lu \ -%lu %lu %lu %lu %lu %lu %lu %lu %d %d %u %u %llu %lu %ld\n", +%lu %lu %lu %lu %lu %lu %lu %lu %d %d %u %u %llu %lu %ld %lu %lu %lu\n", pid_nr_ns(pid, ns), tcomm, state, @@ -511,7 +511,10 @@ static int do_task_stat(struct seq_file task->policy, (unsigned long long)delayacct_blkio_ticks(task), cputime_to_clock_t(gtime), - cputime_to_clock_t(cgtime)); + cputime_to_clock_t(cgtime), + (mm && permitted) ? mm->start_data : 0, + (mm && permitted) ? mm->end_data : 0, + (mm && permitted) ? mm->start_brk : 0); if (mm) mmput(mm); return 0;
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