[v5,00/10] support reinit flow

From: Sinan Kaya <okaya@kernel.org>

We want to be able to call rte_eal_init() and rte_eal_cleanup()
APIs back to back for maintanance reasons.

Here is a summary of the code we have seen so far:

1. some code support getting called multiple times by keeping
a static variable.
2. some code initializes once but never clean up after them and
don't have a cleanup API.
3. some code assumes that they only get called once during the
lifecycle of the process.

Most changes in this patch center around following the #1 design
principle.

Why?

It is not always ideal to reinitialize a DPDK process. Memory needs
to be reinitialized, hugetables need to warm up etc.

Limitations:

This sequence could only be done by main lcore, and never ever in a signal handler.
Do not try and trap signals like abort, bus error, illegal instruction and try to
use this for recovery. It is a recipe for failure.


Changed from

v1:
Fix checkpatch warnings

v2:
rebase to most recent DPDK.

v3:
pick up Stephen's "eal: cleanup plugins data" as a pre-requisite
patch.

v4:
fix windows build
rename variables to run_once where possible
move run_once inside the functions where possible

Graham Whyte (1):
  eal: fixes for re-initialization issues

Sinan Kaya (8):
  tailq: skip init if already initialized
  eal_memzone: bail out on initialized
  memseg: init once
  eal_memory: skip initialization
  eal_interrupts: don't reinitialize threads
  eal: initialize worker threads once
  eal: declare the reinit via cleanup/init feature unsupported
  test: remove double registration check

Stephen Hemminger (1):
  eal: cleanup plugins data

 app/test/test_tailq.c               |  5 ---
 lib/eal/common/eal_common_memory.c  |  6 +++
 lib/eal/common/eal_common_memzone.c |  6 +++
 lib/eal/common/eal_common_options.c | 21 +++++++++
 lib/eal/common/eal_common_tailqs.c  | 20 ++++++---
 lib/eal/common/eal_options.h        |  1 +
 lib/eal/common/malloc_heap.c        |  7 +++
 lib/eal/include/rte_eal.h           |  5 +++
 lib/eal/linux/eal.c                 | 66 ++++++++++++++++-------------
 lib/eal/linux/eal_interrupts.c      |  6 +++
 lib/eal/linux/eal_memory.c          | 12 +++++-
 11 files changed, 113 insertions(+), 42 deletions(-)
  

On Thu, 17 Aug 2023 00:28:11 -0400
okaya@kernel.org wrote:

> From: Sinan Kaya <okaya@kernel.org>
> 
> We want to be able to call rte_eal_init() and rte_eal_cleanup()
> APIs back to back for maintanance reasons.
> 
> Here is a summary of the code we have seen so far:
> 
> 1. some code support getting called multiple times by keeping
> a static variable.
> 2. some code initializes once but never clean up after them and
> don't have a cleanup API.
> 3. some code assumes that they only get called once during the
> lifecycle of the process.
> 
> Most changes in this patch center around following the #1 design
> principle.
> 
> Why?
> 
> It is not always ideal to reinitialize a DPDK process. Memory needs
> to be reinitialized, hugetables need to warm up etc.
> 
> Limitations:
> 
> This sequence could only be done by main lcore, and never ever in a signal handler.
> Do not try and trap signals like abort, bus error, illegal instruction and try to
> use this for recovery. It is a recipe for failure.
> 

This patch series suffers bit rot and does not apply anymore. Needs to be rebase
and resubmit.

There probably needs to be more unit-tests for restart.
Also some documentation for example, for which NIC's does this work?
Probably not all.