Re: [RFC PATCH v8 0/5] IPC: checkpoint/restore in userspace enhancements

From: Stanislav Kinsbursky
Date: Wed Dec 19 2012 - 23:07:28 EST

19.12.2012 00:36, Andrew Morton ÐÐÑÐÑ:
On Wed, 24 Oct 2012 19:34:51 +0400
Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx> wrote:

This respin of the patch set was significantly reworked. Most part of new API
was replaced by sysctls (by one per messages, semaphores and shared memory),
allowing to preset desired id for next new IPC object.

This patch set is aimed to provide additional functionality for all IPC
objects, which is required for migration of these objects by user-space
checkpoint/restore utils (CRIU).

The main problem here was impossibility to set up object id. This patch set
solves the problem by adding new sysctls for preset of desired id for new IPC

Another problem was to peek messages from queues without deleting them.
This was achived by introducing of new MSG_COPY flag for sys_msgrcv(). If
MSG_COPY flag is set, then msgtyp is interpreted as message number.
According to my extensive records, Sasha hit a bug in
ipc-message-queue-copy-feature-introduced.patch and Fengguang found a
bug in

It's not obvious (to me) that these things have been identified and
fixed. What's the status, please?

Hello, Andrew.
Fengguang's issue was solved by "ipc: simplify message copying" I sent you.
But I can't find Sasha's issue. As I remember, there was some problem in early
version of the patch set. But I believe its fixed now.

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