linux/net/Kconfig.debug
Kuniyuki Iwashima 76aed95319 rtnetlink: Add per-netns RTNL.
The goal is to break RTNL down into per-netns mutex.

This patch adds per-netns mutex and its helper functions, rtnl_net_lock()
and rtnl_net_unlock().

rtnl_net_lock() acquires the global RTNL and per-netns RTNL mutex, and
rtnl_net_unlock() releases them.

We will replace 800+ rtnl_lock() with rtnl_net_lock() and finally removes
rtnl_lock() in rtnl_net_lock().

When we need to nest per-netns RTNL mutex, we will use __rtnl_net_lock(),
and its locking order is defined by rtnl_net_lock_cmp_fn() as follows:

  1. init_net is first
  2. netns address ascending order

Note that the conversion will be done under CONFIG_DEBUG_NET_SMALL_RTNL
with LOCKDEP so that we can carefully add the extra mutex without slowing
down RTNL operations during conversion.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-10-08 15:16:59 +02:00

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# SPDX-License-Identifier: GPL-2.0-only
config NET_DEV_REFCNT_TRACKER
bool "Enable net device refcount tracking"
depends on DEBUG_KERNEL && STACKTRACE_SUPPORT && NET
select REF_TRACKER
default n
help
Enable debugging feature to track device references.
This adds memory and cpu costs.
config NET_NS_REFCNT_TRACKER
bool "Enable networking namespace refcount tracking"
depends on DEBUG_KERNEL && STACKTRACE_SUPPORT && NET
select REF_TRACKER
default n
help
Enable debugging feature to track netns references.
This adds memory and cpu costs.
config DEBUG_NET
bool "Add generic networking debug"
depends on DEBUG_KERNEL && NET
help
Enable extra sanity checks in networking.
This is mostly used by fuzzers, but is safe to select.
config DEBUG_NET_SMALL_RTNL
bool "Add extra per-netns mutex inside RTNL"
depends on DEBUG_KERNEL && NET && LOCK_DEBUGGING_SUPPORT
select PROVE_LOCKING
default n
help
rtnl_lock() is being replaced with rtnl_net_lock() that
acquires the global RTNL and a small per-netns RTNL mutex.
During the conversion, rtnl_net_lock() just adds an extra
mutex in every RTNL scope and slows down the operations.
Once the conversion completes, rtnl_lock() will be removed
and rtnetlink will gain per-netns scalability.