Re: [PATCH v3 0/3] mm: kmemleak: Use a memory pool for kmemleak object allocations

[Catalin Marinas <catalin.marinas@arm.com>]

On Tue, Dec 03, 2019 at 03:51:50PM +0000, Noam Stolero wrote:
> On 8/12/2019 7:06 PM, Catalin Marinas wrote:
> >     Following the discussions on v2 of this patch(set) [1], this series
> >     takes slightly different approach:
> > 
> >     - it implements its own simple memory pool that does not rely on the
> >       slab allocator
> > 
> >     - drops the early log buffer logic entirely since it can now allocate
> >       metadata from the memory pool directly before kmemleak is fully
> >       initialised
> > 
> >     - CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE option is renamed to
> >       CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE
> > 
> >     - moves the kmemleak_init() call earlier (mm_init())
> > 
> >     - to avoid a separate memory pool for struct scan_area, it makes the
> >       tool robust when such allocations fail as scan areas are rather an
> >       optimisation
> > 
> >     [1] http://lkml.kernel.org/r/20190727132334.9184-1-catalin.marinas@arm.com
> > 
> >     Catalin Marinas (3):
> >       mm: kmemleak: Make the tool tolerant to struct scan_area allocation
> >         failures
> >       mm: kmemleak: Simple memory allocation pool for kmemleak objects
> >       mm: kmemleak: Use the memory pool for early allocations
> > 
> >      init/main.c       |   2 +-
> >      lib/Kconfig.debug |  11 +-
> >      mm/kmemleak.c     | 325 ++++++++++++----------------------------------
> >      3 files changed, 91 insertions(+), 247 deletions(-)
> 
> We observe severe degradation in our network performance affecting all
> of our NICs. The degradation is directly linked to this patch.
> 
> What we run:
> Simple Iperf TCP loopback with 8 streams on ConnectX5-100GbE.
> Since it's a loopback test, traffic goes from the socket through the IP
> stack and back to the socket, without going through the NIC driver.

Something similar was reported before. Can you try commit 2abd839aa7e6
("kmemleak: Do not corrupt the object_list during clean-up") and see if
it fixes the problem for you? It was merged in 5.4-rc4.

-- 
Catalin