[lkml]   [2013]   [Feb]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread

The code in "kernel/sys.c" provides the "prctl(PR_SET_MM)" function,
which is the only way a process can set or modify the following 11
per-process fields:

start_code, end_code, start_data, end_data, start_brk, brk,
start_stack, arg_start, arg_end, env_start, env_end.

Being able to set those fields is important, even crucial,
for any conceivable user-level checkpointing software, as
well as for migrating processes between different computers.

Unfortunately, this code (essentially "prctl_set_mm()") is presently
enclosed in "#ifdef CONFIG_CHECKPOINT_RESTORE" which is configured
as "default n" in "init/Kconfig". Many system-administrators who
may like to have a checkpoint/restore or process-migration facility,
but use standard pre-packaged kernels, find the requirement to
configure and compile their own non-standard kernel difficult or
too prohibitive.

Would it be possible to have this code enabled by default?

This could be done in one of 4 ways:
1) Having CONFIG_CHECKPOINT_RESTORE enabled by default; or
2) Releasing this code from the "#ifdef CONFIG_CHECK_RESTORE"; or
3) Placing this code within a different kernel-configuration option
(say "CONFIG_BASIC_CHECKPOINTING") that is enabled by default; or
4) Placing this code under a dual #if, so instead of:

Thank you,

 \ /
  Last update: 2013-02-18 03:21    [W:0.217 / U:0.208 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site