| Message ID | 20190812160642.52134-1-catalin.marinas@arm.com |
|---|---|
| Headers | show |
| Series | mm: kmemleak: Use a memory pool for kmemleak object allocations | expand |
On Mon, 12 Aug 2019 17:06:39 +0100 Catalin Marinas <catalin.marinas@arm.com> 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 Using the term "memory pool" is a little unfortunate, but better than using "mempool"! The changelog doesn't answer the very first question: why not use mempools. Please send along a paragraph which explains this decision.
On Mon, Aug 12, 2019 at 02:07:30PM -0700, Andrew Morton wrote: > On Mon, 12 Aug 2019 17:06:39 +0100 Catalin Marinas <catalin.marinas@arm.com> 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 > > Using the term "memory pool" is a little unfortunate, but better than > using "mempool"! I agree, it could have been more inspired. What about "metadata pool" (together with function name updates etc.)? Happy to send a v4. > The changelog doesn't answer the very first question: why not use > mempools. Please send along a paragraph which explains this decision. I posted one in reply to the patch where the changelog should be updated. Thanks. -- Catalin
On 12/3/2019 6:08 PM, Catalin Marinas wrote: > 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. I've tested this commit, as well as 5.4.0-rc6 and 5.4.0 GA versions. We don't see the issue I've mentioned. Thank you for the quick response and the assistance.
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(-)