Thread (27 messages) 27 messages, 8 authors, 2010-03-28

[C/R ARM][PATCH 3/3] c/r: ARM implementation of checkpoint/restart

From: Jamie Lokier <hidden>
Date: 2010-03-26 02:48:15
Also in: lkml

Christoffer Dall wrote:
quoted
That doesn't indicate what ISA version the system is running on, or even
if the ABI is compatible (we have two ABIs - OABI and EABI).
That's why I checkpointed CONFIG_OABI_COMPAT, but I realize that it's
not sufficient.

How about checkpointing CONFIG_AEABI and CONFIG_OABI_COMPAT and making
sure that we either restore to the same setting of the two or restore
to CONFIG_OABI_COMPAT=y?
With CONFIG_OABI_COMPAT enabled, each process can be in either
personality: OABI or EABI.  Checkpointing will need to remember which
one.

With CONFIG_OABI_COMPAT disabled, it'll be fixed at one or the other,
but there's no reason why a process should not be moved between
kernels with different values of CONFIG_OABI_COMPAT, so long as the
OABI or EABI personality is supported by the destination kernel.

In other words, CONFIG_OABI_COMPAT shouldn't be in the checkpoint
state at all - only the per-process personalities should be.
quoted
quoted
We checkpoint whether the system is running with CONFIG_MMU or not and
require the same configuration for the system on which we restore the
process. It might be possible to allow something more fine-grained,
if it's worth the energy. Input on this item is also very welcome,
specifically from someone who knows the exact meaning of the end_brk
field.
Processes which run on MMU and non-MMU CPUs are unlikely to be
interchangable - the run time environments are quite different. ?I
think this is a sane check.
thanks.
It's possible in principle to run many non-MMU binaries on MMU
kernels, but I've never heard of anyone doing it.

-- Jamie
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help