RE: iommu_iova slab eats too much memory
> From: Robin Murphy [mailto:robin.mur...@arm.com] > Sent: Wednesday, April 29, 2020 3:00 PM > To: Salil Mehta ; Bin > > On 2020-04-29 2:37 pm, Salil Mehta wrote: > > Hi Bin, > > > >> From: Bin [mailto:anole1...@gmail.com] > >> Sent: Wednesday, April 29, 2020 5:14 AM > >> To: Salil Mehta > >> Hi Shlil: > >> > >> Thank you for your attention, and these are my answers: > >> > >> 1. I don't really understand what you're saying. What's the difference > >> between > DMA buffer and DMA mapping? > >> It's like a memory block pool and a memory block or something like that? > > > > > > DMA Mapping: Mapping are translations/associations [IOVA<->HPA OR > > IOVA<->GPA(further translated > > to HPA by Stage-2)] which are created by the NIC driver. IOMMU hardware > > responsible for NIC > > IOVA translations is populated with the mappings by the driver before > > submitting the DMA buffer > > to the hardware for TX/RX. > > > > DMA buffers: Actual Memory allocated by the driver where data could be > > DMA'ed (RX'ed or TX'ed) > > > > > > I think you have missed the important point I mentioned earlier: > > If there is a leak of IOVA mapping due to dma_unmap_* not being called > > somewhere then at > > certain point the throughput will drastically fall and will almost become > > equal to zero. > > This is due to the exhaustion of available IOVA mapping space in the IOMMU > > hardware. > > With 64-bit address spaces, you're still likely to run out of memory for > the IOVA structures and pagetables before you run out of the actual > address space that they represent. I see. Good point and it was non-obvious. > The slowdown comes from having to > walk the whole the rbtree to search for free space or free a PFN, but > depending on how the allocation pattern interacts with the caching > mechanism that may never happen to a significant degree. So assuming, due to above limitation of the algorithm allocation of such free mapping space gets delayed, this should only help in more availability of the system memory in general unless this also affects the release of the mappings - perhaps I am missing something here? > > Above condition is very much different than a *memory leak* of the DMA > > buffer > itself which > > will eventually lead to OOM. > > > > > > Salil. > > > >> FYI: > >> I found an interesting phenomenon that it's just a small part of the > >> running > hosts has this issue, even though they all > >> have the same kernel, configuration and hardwares, I don't know if this > >> really > mean something. > > Another thought for a debugging sanity check is to look at the > intel-iommu tracepoints on a misbehaving system and see whether maps vs. > unmaps look significantly out of balance. You could probably do > something clever with ftrace to look for that kind of pattern in teh DMA > API calls, too. > > Robin. > > >> > >> > >> Salil Mehta 于2020年4月28日周二 下午5:17写道： > >> Hi Bin, > >> > >> Few questions: > >> > >> 1. If there is a leak of IOVA due to dma_unmap_* not being called somewhere > then > >> at certain point the throughput will drastically fall and will almost > >> become > >> equal > >> to zero. This should be due to unavailability of the mapping anymore. But > in > >> your > >> case VM is getting killed so this could be actual DMA buffer leak not DMA > mapping > >> leak. I doubt VM will get killed due to exhaustion of the DMA mappings in > the > >> IOMMU > >> Layer for a transient reason or even due to mapping/unmapping leak. > >> > >> 2. Could you check if you have TSO offload enabled on Intel 82599? It will > help > >> in reducing the number of mappings and will take off IOVA mapping pressure > from > >> the IOMMU/VT-d? Though I am not sure it will help in reducing the amount of > memory > >> required for the buffers. > >> > >> 3. Also, have you checked the cpu-usage while your experiment is going on? > >> > >> Thanks > >> Salil. > >> > >>> -Original Message- > >>> From: iommu [mailto:iommu-boun...@lists.linux-foundation.org] On Behalf Of > >>> Robin Murphy > >>> Sent: Friday, April 24, 2020 5:31 PM > >>> To: Bin > >>> Cc: iommu@lists.linux-foundation.org > >>> Subject: Re: iommu_iova slab eats too much memory > >
Re: iommu_iova slab eats too much memory
On 2020-04-29 2:37 pm, Salil Mehta wrote: Hi Bin, From: Bin [mailto:anole1...@gmail.com] Sent: Wednesday, April 29, 2020 5:14 AM To: Salil Mehta Hi Shlil: Thank you for your attention, and these are my answers: 1. I don't really understand what you're saying. What's the difference between DMA buffer and DMA mapping? It's like a memory block pool and a memory block or something like that? DMA Mapping: Mapping are translations/associations [IOVA<->HPA OR IOVA<->GPA(further translated to HPA by Stage-2)] which are created by the NIC driver. IOMMU hardware responsible for NIC IOVA translations is populated with the mappings by the driver before submitting the DMA buffer to the hardware for TX/RX. DMA buffers: Actual Memory allocated by the driver where data could be DMA'ed (RX'ed or TX'ed) I think you have missed the important point I mentioned earlier: If there is a leak of IOVA mapping due to dma_unmap_* not being called somewhere then at certain point the throughput will drastically fall and will almost become equal to zero. This is due to the exhaustion of available IOVA mapping space in the IOMMU hardware. With 64-bit address spaces, you're still likely to run out of memory for the IOVA structures and pagetables before you run out of the actual address space that they represent. The slowdown comes from having to walk the whole the rbtree to search for free space or free a PFN, but depending on how the allocation pattern interacts with the caching mechanism that may never happen to a significant degree. Above condition is very much different than a *memory leak* of the DMA buffer itself which will eventually lead to OOM. Salil. FYI: I found an interesting phenomenon that it's just a small part of the running hosts has this issue, even though they all have the same kernel, configuration and hardwares, I don't know if this really mean something. Another thought for a debugging sanity check is to look at the intel-iommu tracepoints on a misbehaving system and see whether maps vs. unmaps look significantly out of balance. You could probably do something clever with ftrace to look for that kind of pattern in teh DMA API calls, too. Robin. Salil Mehta 于2020年4月28日周二 下午5:17写道： Hi Bin, Few questions: 1. If there is a leak of IOVA due to dma_unmap_* not being called somewhere then at certain point the throughput will drastically fall and will almost become equal to zero. This should be due to unavailability of the mapping anymore. But in your case VM is getting killed so this could be actual DMA buffer leak not DMA mapping leak. I doubt VM will get killed due to exhaustion of the DMA mappings in the IOMMU Layer for a transient reason or even due to mapping/unmapping leak. 2. Could you check if you have TSO offload enabled on Intel 82599? It will help in reducing the number of mappings and will take off IOVA mapping pressure from the IOMMU/VT-d? Though I am not sure it will help in reducing the amount of memory required for the buffers. 3. Also, have you checked the cpu-usage while your experiment is going on? Thanks Salil. -Original Message- From: iommu [mailto:iommu-boun...@lists.linux-foundation.org] On Behalf Of Robin Murphy Sent: Friday, April 24, 2020 5:31 PM To: Bin Cc: iommu@lists.linux-foundation.org Subject: Re: iommu_iova slab eats too much memory On 2020-04-24 2:20 pm, Bin wrote: Dear Robin: Thank you for your explanation. Now, I understand that this could be NIC driver's fault, but how could I confirm it? Do I have to debug the driver myself? I'd start with CONFIG_DMA_API_DEBUG - of course it will chew through memory about an order of magnitude faster than the IOVAs alone, but it should shed some light on whether DMA API usage looks suspicious, and dumping the mappings should help track down the responsible driver(s). Although the debugfs code doesn't show the stacktrace of where each mapping was made, I guess it would be fairly simple to tweak that for a quick way to narrow down where to start looking in an offending driver. Robin. Robin Murphy 于2020年4月24日周五 下午8:15写道： On 2020-04-24 1:06 pm, Bin wrote: I'm not familiar with the mmu stuff, so what you mean by "some driver leaking DMA mappings", is it possible that some other kernel module like KVM or NIC driver leads to the leaking problem instead of the iommu module itself? Yes - I doubt that intel-iommu itself is failing to free IOVAs when it should, since I'd expect a lot of people to have noticed that. It's far more likely that some driver is failing to call dma_unmap_* when it's finished with a buffer - with the IOMMU disabled that would be a no-op on x86 with a modern 64-bit-capable device, so such a latent bug could have been easily overlooked. Robin. Bin 于 2020年4月24日周五 20:00写道： Well, that's the problem! I'm assuming the iommu kernel module is leaking memory. But I don't know why and how. Do you have any idea about it? Or a
RE: iommu_iova slab eats too much memory
Hi Bin, > From: Bin [mailto:anole1...@gmail.com] > Sent: Wednesday, April 29, 2020 5:14 AM > To: Salil Mehta > Hi Shlil: > > Thank you for your attention, and these are my answers: > > 1. I don't really understand what you're saying. What's the difference > between DMA buffer and DMA mapping? > It's like a memory block pool and a memory block or something like that? DMA Mapping: Mapping are translations/associations [IOVA<->HPA OR IOVA<->GPA(further translated to HPA by Stage-2)] which are created by the NIC driver. IOMMU hardware responsible for NIC IOVA translations is populated with the mappings by the driver before submitting the DMA buffer to the hardware for TX/RX. DMA buffers: Actual Memory allocated by the driver where data could be DMA'ed (RX'ed or TX'ed) I think you have missed the important point I mentioned earlier: If there is a leak of IOVA mapping due to dma_unmap_* not being called somewhere then at certain point the throughput will drastically fall and will almost become equal to zero. This is due to the exhaustion of available IOVA mapping space in the IOMMU hardware. Above condition is very much different than a *memory leak* of the DMA buffer itself which will eventually lead to OOM. Salil. > FYI: > I found an interesting phenomenon that it's just a small part of the running > hosts has this issue, even though they all > have the same kernel, configuration and hardwares, I don't know if this > really mean something. > > > Salil Mehta 于2020年4月28日周二 下午5:17写道： > Hi Bin, > > Few questions: > > 1. If there is a leak of IOVA due to dma_unmap_* not being called somewhere > then > at certain point the throughput will drastically fall and will almost become > equal > to zero. This should be due to unavailability of the mapping anymore. But in > your > case VM is getting killed so this could be actual DMA buffer leak not DMA > mapping > leak. I doubt VM will get killed due to exhaustion of the DMA mappings in the > IOMMU > Layer for a transient reason or even due to mapping/unmapping leak. > > 2. Could you check if you have TSO offload enabled on Intel 82599? It will > help > in reducing the number of mappings and will take off IOVA mapping pressure > from > the IOMMU/VT-d? Though I am not sure it will help in reducing the amount of > memory > required for the buffers. > > 3. Also, have you checked the cpu-usage while your experiment is going on? > > Thanks > Salil. > > > -Original Message- > > From: iommu [mailto:iommu-boun...@lists.linux-foundation.org] On Behalf Of > > Robin Murphy > > Sent: Friday, April 24, 2020 5:31 PM > > To: Bin > > Cc: iommu@lists.linux-foundation.org > > Subject: Re: iommu_iova slab eats too much memory > > > > On 2020-04-24 2:20 pm, Bin wrote: > > > Dear Robin: > > > Thank you for your explanation. Now, I understand that this could be > > > NIC driver's fault, but how could I confirm it? Do I have to debug the > > > driver myself? > > > > I'd start with CONFIG_DMA_API_DEBUG - of course it will chew through > > memory about an order of magnitude faster than the IOVAs alone, but it > > should shed some light on whether DMA API usage looks suspicious, and > > dumping the mappings should help track down the responsible driver(s). > > Although the debugfs code doesn't show the stacktrace of where each > > mapping was made, I guess it would be fairly simple to tweak that for a > > quick way to narrow down where to start looking in an offending driver. > > > > Robin. > > > > > Robin Murphy 于2020年4月24日周五 下午8:15写道： > > > > > >> On 2020-04-24 1:06 pm, Bin wrote: > > >>> I'm not familiar with the mmu stuff, so what you mean by "some driver > > >>> leaking DMA mappings", is it possible that some other kernel module like > > >>> KVM or NIC driver leads to the leaking problem instead of the iommu > > >> module > > >>> itself? > > >> > > >> Yes - I doubt that intel-iommu itself is failing to free IOVAs when it > > >> should, since I'd expect a lot of people to have noticed that. It's far > > >> more likely that some driver is failing to call dma_unmap_* when it's > > >> finished with a buffer - with the IOMMU disabled that would be a no-op > > >> on x86 with a modern 64-bit-capable device, so such a latent bug could > > >> have been easily overlooked. > > >> > > >> Robin. > > >> > > >>> Bin 于 2020年4月24日周五 20:00写道： > > >>> > > >>>
Re: iommu_iova slab eats too much memory
Hi Shlil: Thank you for your attention, and these are my answers: 1. I don't really understand what you're saying. What's the difference between DMA buffer and DMA mapping? It's like a memory block pool and a memory block or something like that? 2. Yes, the TSO is enabled all the time, but it seems not helping. 3. The CPU usage is pretty normal, and what's the point of this question? Is it relevant to the leaking problem? FYI: I found an interesting phenomenon that it's just a small part of the running hosts has this issue, even though they all have the same kernel, configuration and hardwares, I don't know if this really mean something. Salil Mehta 于2020年4月28日周二 下午5:17写道： > Hi Bin, > > Few questions: > > 1. If there is a leak of IOVA due to dma_unmap_* not being called > somewhere then > at certain point the throughput will drastically fall and will almost > become equal > to zero. This should be due to unavailability of the mapping anymore. But > in your > case VM is getting killed so this could be actual DMA buffer leak not DMA > mapping > leak. I doubt VM will get killed due to exhaustion of the DMA mappings in > the IOMMU > Layer for a transient reason or even due to mapping/unmapping leak. > > 2. Could you check if you have TSO offload enabled on Intel 82599? It will > help > in reducing the number of mappings and will take off IOVA mapping pressure > from > the IOMMU/VT-d? Though I am not sure it will help in reducing the amount > of memory > required for the buffers. > > 3. Also, have you checked the cpu-usage while your experiment is going on? > > Thanks > Salil. > > > -Original Message- > > From: iommu [mailto:iommu-boun...@lists.linux-foundation.org] On Behalf > Of > > Robin Murphy > > Sent: Friday, April 24, 2020 5:31 PM > > To: Bin > > Cc: iommu@lists.linux-foundation.org > > Subject: Re: iommu_iova slab eats too much memory > > > > On 2020-04-24 2:20 pm, Bin wrote: > > > Dear Robin: > > > Thank you for your explanation. Now, I understand that this could > be > > > NIC driver's fault, but how could I confirm it? Do I have to debug the > > > driver myself? > > > > I'd start with CONFIG_DMA_API_DEBUG - of course it will chew through > > memory about an order of magnitude faster than the IOVAs alone, but it > > should shed some light on whether DMA API usage looks suspicious, and > > dumping the mappings should help track down the responsible driver(s). > > Although the debugfs code doesn't show the stacktrace of where each > > mapping was made, I guess it would be fairly simple to tweak that for a > > quick way to narrow down where to start looking in an offending driver. > > > > Robin. > > > > > Robin Murphy 于2020年4月24日周五 下午8:15写道： > > > > > >> On 2020-04-24 1:06 pm, Bin wrote: > > >>> I'm not familiar with the mmu stuff, so what you mean by "some driver > > >>> leaking DMA mappings", is it possible that some other kernel module > like > > >>> KVM or NIC driver leads to the leaking problem instead of the iommu > > >> module > > >>> itself? > > >> > > >> Yes - I doubt that intel-iommu itself is failing to free IOVAs when it > > >> should, since I'd expect a lot of people to have noticed that. It's > far > > >> more likely that some driver is failing to call dma_unmap_* when it's > > >> finished with a buffer - with the IOMMU disabled that would be a no-op > > >> on x86 with a modern 64-bit-capable device, so such a latent bug could > > >> have been easily overlooked. > > >> > > >> Robin. > > >> > > >>> Bin 于 2020年4月24日周五 20:00写道： > > >>> > > >>>> Well, that's the problem! I'm assuming the iommu kernel module is > > >> leaking > > >>>> memory. But I don't know why and how. > > >>>> > > >>>> Do you have any idea about it? Or any further information is needed? > > >>>> > > >>>> Robin Murphy 于 2020年4月24日周五 19:20写道： > > >>>> > > >>>>> On 2020-04-24 1:40 am, Bin wrote: > > >>>>>> Hello? anyone there? > > >>>>>> > > >>>>>> Bin 于2020年4月23日周四 下午5:14写道： > > >>>>>> > > >>>>>>> Forget to mention, I've already disabled the slab merge, so this > is > > >>>>> what > > >>>>>>> it is. > > >>>>>>> > > >>>>&g
RE: iommu_iova slab eats too much memory
Hi Bin, Few questions: 1. If there is a leak of IOVA due to dma_unmap_* not being called somewhere then at certain point the throughput will drastically fall and will almost become equal to zero. This should be due to unavailability of the mapping anymore. But in your case VM is getting killed so this could be actual DMA buffer leak not DMA mapping leak. I doubt VM will get killed due to exhaustion of the DMA mappings in the IOMMU Layer for a transient reason or even due to mapping/unmapping leak. 2. Could you check if you have TSO offload enabled on Intel 82599? It will help in reducing the number of mappings and will take off IOVA mapping pressure from the IOMMU/VT-d? Though I am not sure it will help in reducing the amount of memory required for the buffers. 3. Also, have you checked the cpu-usage while your experiment is going on? Thanks Salil. > -Original Message- > From: iommu [mailto:iommu-boun...@lists.linux-foundation.org] On Behalf Of > Robin Murphy > Sent: Friday, April 24, 2020 5:31 PM > To: Bin > Cc: iommu@lists.linux-foundation.org > Subject: Re: iommu_iova slab eats too much memory > > On 2020-04-24 2:20 pm, Bin wrote: > > Dear Robin: > > Thank you for your explanation. Now, I understand that this could be > > NIC driver's fault, but how could I confirm it? Do I have to debug the > > driver myself? > > I'd start with CONFIG_DMA_API_DEBUG - of course it will chew through > memory about an order of magnitude faster than the IOVAs alone, but it > should shed some light on whether DMA API usage looks suspicious, and > dumping the mappings should help track down the responsible driver(s). > Although the debugfs code doesn't show the stacktrace of where each > mapping was made, I guess it would be fairly simple to tweak that for a > quick way to narrow down where to start looking in an offending driver. > > Robin. > > > Robin Murphy 于2020年4月24日周五 下午8:15写道： > > > >> On 2020-04-24 1:06 pm, Bin wrote: > >>> I'm not familiar with the mmu stuff, so what you mean by "some driver > >>> leaking DMA mappings", is it possible that some other kernel module like > >>> KVM or NIC driver leads to the leaking problem instead of the iommu > >> module > >>> itself? > >> > >> Yes - I doubt that intel-iommu itself is failing to free IOVAs when it > >> should, since I'd expect a lot of people to have noticed that. It's far > >> more likely that some driver is failing to call dma_unmap_* when it's > >> finished with a buffer - with the IOMMU disabled that would be a no-op > >> on x86 with a modern 64-bit-capable device, so such a latent bug could > >> have been easily overlooked. > >> > >> Robin. > >> > >>> Bin 于 2020年4月24日周五 20:00写道： > >>> > >>>> Well, that's the problem! I'm assuming the iommu kernel module is > >> leaking > >>>> memory. But I don't know why and how. > >>>> > >>>> Do you have any idea about it? Or any further information is needed? > >>>> > >>>> Robin Murphy 于 2020年4月24日周五 19:20写道： > >>>> > >>>>> On 2020-04-24 1:40 am, Bin wrote: > >>>>>> Hello? anyone there? > >>>>>> > >>>>>> Bin 于2020年4月23日周四 下午5:14写道： > >>>>>> > >>>>>>> Forget to mention, I've already disabled the slab merge, so this is > >>>>> what > >>>>>>> it is. > >>>>>>> > >>>>>>> Bin 于2020年4月23日周四 下午5:11写道： > >>>>>>> > >>>>>>>> Hey, guys: > >>>>>>>> > >>>>>>>> I'm running a batch of CoreOS boxes, the lsb_release is: > >>>>>>>> > >>>>>>>> ``` > >>>>>>>> # cat /etc/lsb-release > >>>>>>>> DISTRIB_ID="Container Linux by CoreOS" > >>>>>>>> DISTRIB_RELEASE=2303.3.0 > >>>>>>>> DISTRIB_CODENAME="Rhyolite" > >>>>>>>> DISTRIB_DESCRIPTION="Container Linux by CoreOS 2303.3.0 (Rhyolite)" > >>>>>>>> ``` > >>>>>>>> > >>>>>>>> ``` > >>>>>>>> # uname -a > >>>>>>>> Linux cloud-worker-25 4.19.86-coreos #1 SMP Mon Dec 2 20:13:38 -00 > >>>>> 2019 > >>>>>>>> x86_64 Intel(R) Xeon(R) CPU E5-2640 v2 @ 2.00GHz Ge
Re: iommu_iova slab eats too much memory
Dear John: Thank you for your reply. The case you mentioned is a typical performance regression issue, there's no need for the kernel to oom kill any random process even in the worst case. But in my observations, the iommu_iova slab could consume up to 40G memory, and the kernel have to kill my vm process to free memory (64G memory installed). So I don't think it's relevent. John Garry 于2020年4月25日周六 上午1:50写道： > On 24/04/2020 17:30, Robin Murphy wrote: > > On 2020-04-24 2:20 pm, Bin wrote: > >> Dear Robin: > >> Thank you for your explanation. Now, I understand that this could > be > >> NIC driver's fault, but how could I confirm it? Do I have to debug the > >> driver myself? > > > > I'd start with CONFIG_DMA_API_DEBUG - of course it will chew through > > memory about an order of magnitude faster than the IOVAs alone, but it > > should shed some light on whether DMA API usage looks suspicious, and > > dumping the mappings should help track down the responsible driver(s). > > Although the debugfs code doesn't show the stacktrace of where each > > mapping was made, I guess it would be fairly simple to tweak that for a > > quick way to narrow down where to start looking in an offending driver. > > > > Robin. > > Just mentioning this in case it's relevant - we found long term aging > throughput test causes RB tree to grow very large (and would I assume > eat lots of memory): > > > https://lore.kernel.org/linux-iommu/20190815121104.29140-3-thunder.leiz...@huawei.com/ > > John > > > > >> Robin Murphy 于2020年4月24日周五 下午8:15写道： > >> > >>> On 2020-04-24 1:06 pm, Bin wrote: > I'm not familiar with the mmu stuff, so what you mean by "some driver > leaking DMA mappings", is it possible that some other kernel module > like > KVM or NIC driver leads to the leaking problem instead of the iommu > >>> module > itself? > >>> > >>> Yes - I doubt that intel-iommu itself is failing to free IOVAs when it > >>> should, since I'd expect a lot of people to have noticed that. It's far > >>> more likely that some driver is failing to call dma_unmap_* when it's > >>> finished with a buffer - with the IOMMU disabled that would be a no-op > >>> on x86 with a modern 64-bit-capable device, so such a latent bug could > >>> have been easily overlooked. > >>> > >>> Robin. > >>> > Bin 于 2020年4月24日周五 20:00写道： > > > Well, that's the problem! I'm assuming the iommu kernel module is > >>> leaking > > memory. But I don't know why and how. > > > > Do you have any idea about it? Or any further information is needed? > > > > Robin Murphy 于 2020年4月24日周五 19:20写道： > > > >> On 2020-04-24 1:40 am, Bin wrote: > >>> Hello? anyone there? > >>> > >>> Bin 于2020年4月23日周四 下午5:14写道： > >>> > Forget to mention, I've already disabled the slab merge, so this > is > >> what > it is. > > Bin 于2020年4月23日周四 下午5:11写道： > > > Hey, guys: > > > > I'm running a batch of CoreOS boxes, the lsb_release is: > > > > ``` > > # cat /etc/lsb-release > > DISTRIB_ID="Container Linux by CoreOS" > > DISTRIB_RELEASE=2303.3.0 > > DISTRIB_CODENAME="Rhyolite" > > DISTRIB_DESCRIPTION="Container Linux by CoreOS 2303.3.0 > (Rhyolite)" > > ``` > > > > ``` > > # uname -a > > Linux cloud-worker-25 4.19.86-coreos #1 SMP Mon Dec 2 20:13:38 > -00 > >> 2019 > > x86_64 Intel(R) Xeon(R) CPU E5-2640 v2 @ 2.00GHz GenuineIntel > >> GNU/Linux > > ``` > > Recently, I found my vms constently being killed due to OOM, and > >>> after > > digging into the problem, I finally realized that the kernel is > >> leaking > > memory. > > > > Here's my slabinfo: > > > > Active / Total Objects (% used): 83818306 / 84191607 > (99.6%) > > Active / Total Slabs (% used) : 1336293 / 1336293 > (100.0%) > > Active / Total Caches (% used) : 152 / 217 (70.0%) > > Active / Total Size (% used) : 5828768.08K / > 5996848.72K > >> (97.2%) > > Minimum / Average / Maximum Object : 0.01K / 0.07K / 23.25K > > > > OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME > > > > 80253888 80253888 100%0.06K 1253967 64 5015868K > >>> iommu_iova > >> > >> Do you really have a peak demand of ~80 million simultaneous DMA > >> buffers, or is some driver leaking DMA mappings? > >> > >> Robin. > >> > > 489472 489123 99%0.03K 3824 128 15296K kmalloc-32 > > > > 297444 271112 91%0.19K 7082 42 56656K dentry > > > > 254400 252784 99%0.06K 3975 64 15900K > >>> anon_vma_chain > > > > 222528 39255 17%0.50K 6954 32111264K > kmalloc-512 >
Re: iommu_iova slab eats too much memory
On 24/04/2020 17:30, Robin Murphy wrote: On 2020-04-24 2:20 pm, Bin wrote: Dear Robin: Thank you for your explanation. Now, I understand that this could be NIC driver's fault, but how could I confirm it? Do I have to debug the driver myself? I'd start with CONFIG_DMA_API_DEBUG - of course it will chew through memory about an order of magnitude faster than the IOVAs alone, but it should shed some light on whether DMA API usage looks suspicious, and dumping the mappings should help track down the responsible driver(s). Although the debugfs code doesn't show the stacktrace of where each mapping was made, I guess it would be fairly simple to tweak that for a quick way to narrow down where to start looking in an offending driver. Robin. Just mentioning this in case it's relevant - we found long term aging throughput test causes RB tree to grow very large (and would I assume eat lots of memory): https://lore.kernel.org/linux-iommu/20190815121104.29140-3-thunder.leiz...@huawei.com/ John Robin Murphy 于2020年4月24日周五 下午8:15写道： On 2020-04-24 1:06 pm, Bin wrote: I'm not familiar with the mmu stuff, so what you mean by "some driver leaking DMA mappings", is it possible that some other kernel module like KVM or NIC driver leads to the leaking problem instead of the iommu module itself? Yes - I doubt that intel-iommu itself is failing to free IOVAs when it should, since I'd expect a lot of people to have noticed that. It's far more likely that some driver is failing to call dma_unmap_* when it's finished with a buffer - with the IOMMU disabled that would be a no-op on x86 with a modern 64-bit-capable device, so such a latent bug could have been easily overlooked. Robin. Bin 于 2020年4月24日周五 20:00写道： Well, that's the problem! I'm assuming the iommu kernel module is leaking memory. But I don't know why and how. Do you have any idea about it? Or any further information is needed? Robin Murphy 于 2020年4月24日周五 19:20写道： On 2020-04-24 1:40 am, Bin wrote: Hello? anyone there? Bin 于2020年4月23日周四 下午5:14写道： Forget to mention, I've already disabled the slab merge, so this is what it is. Bin 于2020年4月23日周四 下午5:11写道： Hey, guys: I'm running a batch of CoreOS boxes, the lsb_release is: ``` # cat /etc/lsb-release DISTRIB_ID="Container Linux by CoreOS" DISTRIB_RELEASE=2303.3.0 DISTRIB_CODENAME="Rhyolite" DISTRIB_DESCRIPTION="Container Linux by CoreOS 2303.3.0 (Rhyolite)" ``` ``` # uname -a Linux cloud-worker-25 4.19.86-coreos #1 SMP Mon Dec 2 20:13:38 -00 2019 x86_64 Intel(R) Xeon(R) CPU E5-2640 v2 @ 2.00GHz GenuineIntel GNU/Linux ``` Recently, I found my vms constently being killed due to OOM, and after digging into the problem, I finally realized that the kernel is leaking memory. Here's my slabinfo: Active / Total Objects (% used): 83818306 / 84191607 (99.6%) Active / Total Slabs (% used) : 1336293 / 1336293 (100.0%) Active / Total Caches (% used) : 152 / 217 (70.0%) Active / Total Size (% used) : 5828768.08K / 5996848.72K (97.2%) Minimum / Average / Maximum Object : 0.01K / 0.07K / 23.25K OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME 80253888 80253888 100%0.06K 1253967 64 5015868K iommu_iova Do you really have a peak demand of ~80 million simultaneous DMA buffers, or is some driver leaking DMA mappings? Robin. 489472 489123 99%0.03K 3824 128 15296K kmalloc-32 297444 271112 91%0.19K 7082 42 56656K dentry 254400 252784 99%0.06K 3975 64 15900K anon_vma_chain 222528 39255 17%0.50K 6954 32111264K kmalloc-512 202482 201814 99%0.19K 4821 42 38568K vm_area_struct 200192 200192 100%0.01K391 512 1564K kmalloc-8 170528 169359 99%0.25K 5329 32 42632K filp 158144 153508 97%0.06K 2471 64 9884K kmalloc-64 149914 149365 99%0.09K 3259 46 13036K anon_vma 146640 143123 97%0.10K 3760 39 15040K buffer_head 130368 32791 25%0.09K 3104 42 12416K kmalloc-96 129752 129752 100%0.07K 2317 56 9268K Acpi-Operand 105468 105106 99%0.04K 1034 102 4136K selinux_inode_security 73080 73080 100%0.13K 2436 30 9744K kernfs_node_cache 72360 70261 97%0.59K 1340 54 42880K inode_cache 71040 71040 100%0.12K 2220 32 8880K eventpoll_epi 68096 59262 87%0.02K266 256 1064K kmalloc-16 53652 53652 100%0.04K526 102 2104K pde_opener 50496 31654 62%2.00K 3156 16100992K kmalloc-2048 46242 46242 100%0.19K 1101 42 8808K cred_jar 44496 43013 96%0.66K927 48 29664K proc_inode_cache 44352 44352 100%0.06K693 64 2772K task_delay_info 43516 43471 99%0.69K946 46
Re: iommu_iova slab eats too much memory
On 2020-04-24 2:20 pm, Bin wrote: Dear Robin: Thank you for your explanation. Now, I understand that this could be NIC driver's fault, but how could I confirm it? Do I have to debug the driver myself? I'd start with CONFIG_DMA_API_DEBUG - of course it will chew through memory about an order of magnitude faster than the IOVAs alone, but it should shed some light on whether DMA API usage looks suspicious, and dumping the mappings should help track down the responsible driver(s). Although the debugfs code doesn't show the stacktrace of where each mapping was made, I guess it would be fairly simple to tweak that for a quick way to narrow down where to start looking in an offending driver. Robin. Robin Murphy 于2020年4月24日周五 下午8:15写道： On 2020-04-24 1:06 pm, Bin wrote: I'm not familiar with the mmu stuff, so what you mean by "some driver leaking DMA mappings", is it possible that some other kernel module like KVM or NIC driver leads to the leaking problem instead of the iommu module itself? Yes - I doubt that intel-iommu itself is failing to free IOVAs when it should, since I'd expect a lot of people to have noticed that. It's far more likely that some driver is failing to call dma_unmap_* when it's finished with a buffer - with the IOMMU disabled that would be a no-op on x86 with a modern 64-bit-capable device, so such a latent bug could have been easily overlooked. Robin. Bin 于 2020年4月24日周五 20:00写道： Well, that's the problem! I'm assuming the iommu kernel module is leaking memory. But I don't know why and how. Do you have any idea about it? Or any further information is needed? Robin Murphy 于 2020年4月24日周五 19:20写道： On 2020-04-24 1:40 am, Bin wrote: Hello? anyone there? Bin 于2020年4月23日周四 下午5:14写道： Forget to mention, I've already disabled the slab merge, so this is what it is. Bin 于2020年4月23日周四 下午5:11写道： Hey, guys: I'm running a batch of CoreOS boxes, the lsb_release is: ``` # cat /etc/lsb-release DISTRIB_ID="Container Linux by CoreOS" DISTRIB_RELEASE=2303.3.0 DISTRIB_CODENAME="Rhyolite" DISTRIB_DESCRIPTION="Container Linux by CoreOS 2303.3.0 (Rhyolite)" ``` ``` # uname -a Linux cloud-worker-25 4.19.86-coreos #1 SMP Mon Dec 2 20:13:38 -00 2019 x86_64 Intel(R) Xeon(R) CPU E5-2640 v2 @ 2.00GHz GenuineIntel GNU/Linux ``` Recently, I found my vms constently being killed due to OOM, and after digging into the problem, I finally realized that the kernel is leaking memory. Here's my slabinfo: Active / Total Objects (% used): 83818306 / 84191607 (99.6%) Active / Total Slabs (% used) : 1336293 / 1336293 (100.0%) Active / Total Caches (% used) : 152 / 217 (70.0%) Active / Total Size (% used) : 5828768.08K / 5996848.72K (97.2%) Minimum / Average / Maximum Object : 0.01K / 0.07K / 23.25K OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME 80253888 80253888 100%0.06K 1253967 64 5015868K iommu_iova Do you really have a peak demand of ~80 million simultaneous DMA buffers, or is some driver leaking DMA mappings? Robin. 489472 489123 99%0.03K 3824 128 15296K kmalloc-32 297444 271112 91%0.19K 7082 42 56656K dentry 254400 252784 99%0.06K 3975 64 15900K anon_vma_chain 222528 39255 17%0.50K 6954 32111264K kmalloc-512 202482 201814 99%0.19K 4821 42 38568K vm_area_struct 200192 200192 100%0.01K391 512 1564K kmalloc-8 170528 169359 99%0.25K 5329 32 42632K filp 158144 153508 97%0.06K 2471 64 9884K kmalloc-64 149914 149365 99%0.09K 3259 46 13036K anon_vma 146640 143123 97%0.10K 3760 39 15040K buffer_head 130368 32791 25%0.09K 3104 42 12416K kmalloc-96 129752 129752 100%0.07K 2317 56 9268K Acpi-Operand 105468 105106 99%0.04K 1034 102 4136K selinux_inode_security 73080 73080 100%0.13K 2436 30 9744K kernfs_node_cache 72360 70261 97%0.59K 1340 54 42880K inode_cache 71040 71040 100%0.12K 2220 32 8880K eventpoll_epi 68096 59262 87%0.02K266 256 1064K kmalloc-16 53652 53652 100%0.04K526 102 2104K pde_opener 50496 31654 62%2.00K 3156 16100992K kmalloc-2048 46242 46242 100%0.19K 1101 42 8808K cred_jar 44496 43013 96%0.66K927 48 29664K proc_inode_cache 44352 44352 100%0.06K693 64 2772K task_delay_info 43516 43471 99%0.69K946 46 30272K sock_inode_cache 37856 27626 72%1.00K 1183 32 37856K kmalloc-1024 36736 36736 100%0.07K656 56 2624K eventpoll_pwq 34076 31282 91%0.57K 1217 28 19472K radix_tree_node 33660 30528 90%1.05K 1122 30 35904K
Re: iommu_iova slab eats too much memory
Dear Robin: Thank you for your explanation. Now, I understand that this could be NIC driver's fault, but how could I confirm it? Do I have to debug the driver myself? Robin Murphy 于2020年4月24日周五 下午8:15写道： > On 2020-04-24 1:06 pm, Bin wrote: > > I'm not familiar with the mmu stuff, so what you mean by "some driver > > leaking DMA mappings", is it possible that some other kernel module like > > KVM or NIC driver leads to the leaking problem instead of the iommu > module > > itself? > > Yes - I doubt that intel-iommu itself is failing to free IOVAs when it > should, since I'd expect a lot of people to have noticed that. It's far > more likely that some driver is failing to call dma_unmap_* when it's > finished with a buffer - with the IOMMU disabled that would be a no-op > on x86 with a modern 64-bit-capable device, so such a latent bug could > have been easily overlooked. > > Robin. > > > Bin 于 2020年4月24日周五 20:00写道： > > > >> Well, that's the problem! I'm assuming the iommu kernel module is > leaking > >> memory. But I don't know why and how. > >> > >> Do you have any idea about it? Or any further information is needed? > >> > >> Robin Murphy 于 2020年4月24日周五 19:20写道： > >> > >>> On 2020-04-24 1:40 am, Bin wrote: > Hello? anyone there? > > Bin 于2020年4月23日周四 下午5:14写道： > > > Forget to mention, I've already disabled the slab merge, so this is > >>> what > > it is. > > > > Bin 于2020年4月23日周四 下午5:11写道： > > > >> Hey, guys: > >> > >> I'm running a batch of CoreOS boxes, the lsb_release is: > >> > >> ``` > >> # cat /etc/lsb-release > >> DISTRIB_ID="Container Linux by CoreOS" > >> DISTRIB_RELEASE=2303.3.0 > >> DISTRIB_CODENAME="Rhyolite" > >> DISTRIB_DESCRIPTION="Container Linux by CoreOS 2303.3.0 (Rhyolite)" > >> ``` > >> > >> ``` > >> # uname -a > >> Linux cloud-worker-25 4.19.86-coreos #1 SMP Mon Dec 2 20:13:38 -00 > >>> 2019 > >> x86_64 Intel(R) Xeon(R) CPU E5-2640 v2 @ 2.00GHz GenuineIntel > >>> GNU/Linux > >> ``` > >> Recently, I found my vms constently being killed due to OOM, and > after > >> digging into the problem, I finally realized that the kernel is > >>> leaking > >> memory. > >> > >> Here's my slabinfo: > >> > >>Active / Total Objects (% used): 83818306 / 84191607 (99.6%) > >>Active / Total Slabs (% used) : 1336293 / 1336293 (100.0%) > >>Active / Total Caches (% used) : 152 / 217 (70.0%) > >>Active / Total Size (% used) : 5828768.08K / 5996848.72K > >>> (97.2%) > >>Minimum / Average / Maximum Object : 0.01K / 0.07K / 23.25K > >> > >> OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME > >> > >> 80253888 80253888 100%0.06K 1253967 64 5015868K > iommu_iova > >>> > >>> Do you really have a peak demand of ~80 million simultaneous DMA > >>> buffers, or is some driver leaking DMA mappings? > >>> > >>> Robin. > >>> > >> 489472 489123 99%0.03K 3824 128 15296K kmalloc-32 > >> > >> 297444 271112 91%0.19K 7082 42 56656K dentry > >> > >> 254400 252784 99%0.06K 3975 64 15900K > anon_vma_chain > >> > >> 222528 39255 17%0.50K 6954 32111264K kmalloc-512 > >> > >> 202482 201814 99%0.19K 4821 42 38568K > vm_area_struct > >> > >> 200192 200192 100%0.01K391 512 1564K kmalloc-8 > >> > >> 170528 169359 99%0.25K 5329 32 42632K filp > >> > >> 158144 153508 97%0.06K 2471 64 9884K kmalloc-64 > >> > >> 149914 149365 99%0.09K 3259 46 13036K anon_vma > >> > >> 146640 143123 97%0.10K 3760 39 15040K buffer_head > >> > >> 130368 32791 25%0.09K 3104 42 12416K kmalloc-96 > >> > >> 129752 129752 100%0.07K 2317 56 9268K Acpi-Operand > >> > >> 105468 105106 99%0.04K 1034 102 4136K > >> selinux_inode_security > >>73080 73080 100%0.13K 2436 30 9744K > >>> kernfs_node_cache > >> > >>72360 70261 97%0.59K 1340 54 42880K inode_cache > >> > >>71040 71040 100%0.12K 2220 32 8880K > eventpoll_epi > >> > >>68096 59262 87%0.02K266 256 1064K kmalloc-16 > >> > >>53652 53652 100%0.04K526 102 2104K pde_opener > >> > >>50496 31654 62%2.00K 3156 16100992K > kmalloc-2048 > >> > >>46242 46242 100%0.19K 1101 42 8808K cred_jar > >> > >>44496 43013 96%0.66K927 48 29664K > >>> proc_inode_cache > >> > >>44352 44352 100%0.06K693 64 2772K > >>> task_delay_info > >> > >>43516 43471 99%0.69K946 46 30272K > >>>
Re: iommu_iova slab eats too much memory
On 2020-04-24 1:06 pm, Bin wrote: I'm not familiar with the mmu stuff, so what you mean by "some driver leaking DMA mappings", is it possible that some other kernel module like KVM or NIC driver leads to the leaking problem instead of the iommu module itself? Yes - I doubt that intel-iommu itself is failing to free IOVAs when it should, since I'd expect a lot of people to have noticed that. It's far more likely that some driver is failing to call dma_unmap_* when it's finished with a buffer - with the IOMMU disabled that would be a no-op on x86 with a modern 64-bit-capable device, so such a latent bug could have been easily overlooked. Robin. Bin 于 2020年4月24日周五 20:00写道： Well, that's the problem! I'm assuming the iommu kernel module is leaking memory. But I don't know why and how. Do you have any idea about it? Or any further information is needed? Robin Murphy 于 2020年4月24日周五 19:20写道： On 2020-04-24 1:40 am, Bin wrote: Hello? anyone there? Bin 于2020年4月23日周四 下午5:14写道： Forget to mention, I've already disabled the slab merge, so this is what it is. Bin 于2020年4月23日周四 下午5:11写道： Hey, guys: I'm running a batch of CoreOS boxes, the lsb_release is: ``` # cat /etc/lsb-release DISTRIB_ID="Container Linux by CoreOS" DISTRIB_RELEASE=2303.3.0 DISTRIB_CODENAME="Rhyolite" DISTRIB_DESCRIPTION="Container Linux by CoreOS 2303.3.0 (Rhyolite)" ``` ``` # uname -a Linux cloud-worker-25 4.19.86-coreos #1 SMP Mon Dec 2 20:13:38 -00 2019 x86_64 Intel(R) Xeon(R) CPU E5-2640 v2 @ 2.00GHz GenuineIntel GNU/Linux ``` Recently, I found my vms constently being killed due to OOM, and after digging into the problem, I finally realized that the kernel is leaking memory. Here's my slabinfo: Active / Total Objects (% used): 83818306 / 84191607 (99.6%) Active / Total Slabs (% used) : 1336293 / 1336293 (100.0%) Active / Total Caches (% used) : 152 / 217 (70.0%) Active / Total Size (% used) : 5828768.08K / 5996848.72K (97.2%) Minimum / Average / Maximum Object : 0.01K / 0.07K / 23.25K OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME 80253888 80253888 100%0.06K 1253967 64 5015868K iommu_iova Do you really have a peak demand of ~80 million simultaneous DMA buffers, or is some driver leaking DMA mappings? Robin. 489472 489123 99%0.03K 3824 128 15296K kmalloc-32 297444 271112 91%0.19K 7082 42 56656K dentry 254400 252784 99%0.06K 3975 64 15900K anon_vma_chain 222528 39255 17%0.50K 6954 32111264K kmalloc-512 202482 201814 99%0.19K 4821 42 38568K vm_area_struct 200192 200192 100%0.01K391 512 1564K kmalloc-8 170528 169359 99%0.25K 5329 32 42632K filp 158144 153508 97%0.06K 2471 64 9884K kmalloc-64 149914 149365 99%0.09K 3259 46 13036K anon_vma 146640 143123 97%0.10K 3760 39 15040K buffer_head 130368 32791 25%0.09K 3104 42 12416K kmalloc-96 129752 129752 100%0.07K 2317 56 9268K Acpi-Operand 105468 105106 99%0.04K 1034 102 4136K selinux_inode_security 73080 73080 100%0.13K 2436 30 9744K kernfs_node_cache 72360 70261 97%0.59K 1340 54 42880K inode_cache 71040 71040 100%0.12K 2220 32 8880K eventpoll_epi 68096 59262 87%0.02K266 256 1064K kmalloc-16 53652 53652 100%0.04K526 102 2104K pde_opener 50496 31654 62%2.00K 3156 16100992K kmalloc-2048 46242 46242 100%0.19K 1101 42 8808K cred_jar 44496 43013 96%0.66K927 48 29664K proc_inode_cache 44352 44352 100%0.06K693 64 2772K task_delay_info 43516 43471 99%0.69K946 46 30272K sock_inode_cache 37856 27626 72%1.00K 1183 32 37856K kmalloc-1024 36736 36736 100%0.07K656 56 2624K eventpoll_pwq 34076 31282 91%0.57K 1217 28 19472K radix_tree_node 33660 30528 90%1.05K 1122 30 35904K ext4_inode_cache 32760 30959 94%0.19K780 42 6240K kmalloc-192 32028 32028 100%0.04K314 102 1256K ext4_extent_status 30048 30048 100%0.25K939 32 7512K skbuff_head_cache 28736 28736 100%0.06K449 64 1796K fs_cache 24702 24702 100%0.69K537 46 17184K files_cache 23808 23808 100%0.66K496 48 15872K ovl_inode 23104 22945 99%0.12K722 32 2888K kmalloc-128 22724 21307 93%0.69K494 46 15808K shmem_inode_cache 21472 21472 100%0.12K671 32 2684K seq_file 19904 19904 100%1.00K622 32 19904K UNIX 17340 17340 100%1.06K578 30 18496K mm_struct
Re: iommu_iova slab eats too much memory
I'm not familiar with the mmu stuff, so what you mean by "some driver leaking DMA mappings", is it possible that some other kernel module like KVM or NIC driver leads to the leaking problem instead of the iommu module itself? Bin 于 2020年4月24日周五 20:00写道： > Well, that's the problem! I'm assuming the iommu kernel module is leaking > memory. But I don't know why and how. > > Do you have any idea about it? Or any further information is needed? > > Robin Murphy 于 2020年4月24日周五 19:20写道： > >> On 2020-04-24 1:40 am, Bin wrote: >> > Hello? anyone there? >> > >> > Bin 于2020年4月23日周四 下午5:14写道： >> > >> >> Forget to mention, I've already disabled the slab merge, so this is >> what >> >> it is. >> >> >> >> Bin 于2020年4月23日周四 下午5:11写道： >> >> >> >>> Hey, guys: >> >>> >> >>> I'm running a batch of CoreOS boxes, the lsb_release is: >> >>> >> >>> ``` >> >>> # cat /etc/lsb-release >> >>> DISTRIB_ID="Container Linux by CoreOS" >> >>> DISTRIB_RELEASE=2303.3.0 >> >>> DISTRIB_CODENAME="Rhyolite" >> >>> DISTRIB_DESCRIPTION="Container Linux by CoreOS 2303.3.0 (Rhyolite)" >> >>> ``` >> >>> >> >>> ``` >> >>> # uname -a >> >>> Linux cloud-worker-25 4.19.86-coreos #1 SMP Mon Dec 2 20:13:38 -00 >> 2019 >> >>> x86_64 Intel(R) Xeon(R) CPU E5-2640 v2 @ 2.00GHz GenuineIntel >> GNU/Linux >> >>> ``` >> >>> Recently, I found my vms constently being killed due to OOM, and after >> >>> digging into the problem, I finally realized that the kernel is >> leaking >> >>> memory. >> >>> >> >>> Here's my slabinfo: >> >>> >> >>> Active / Total Objects (% used): 83818306 / 84191607 (99.6%) >> >>> Active / Total Slabs (% used) : 1336293 / 1336293 (100.0%) >> >>> Active / Total Caches (% used) : 152 / 217 (70.0%) >> >>> Active / Total Size (% used) : 5828768.08K / 5996848.72K >> (97.2%) >> >>> Minimum / Average / Maximum Object : 0.01K / 0.07K / 23.25K >> >>> >> >>>OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME >> >>> >> >>> 80253888 80253888 100%0.06K 1253967 64 5015868K iommu_iova >> >> Do you really have a peak demand of ~80 million simultaneous DMA >> buffers, or is some driver leaking DMA mappings? >> >> Robin. >> >> >>> 489472 489123 99%0.03K 3824 128 15296K kmalloc-32 >> >>> >> >>> 297444 271112 91%0.19K 7082 42 56656K dentry >> >>> >> >>> 254400 252784 99%0.06K 3975 64 15900K anon_vma_chain >> >>> >> >>> 222528 39255 17%0.50K 6954 32111264K kmalloc-512 >> >>> >> >>> 202482 201814 99%0.19K 4821 42 38568K vm_area_struct >> >>> >> >>> 200192 200192 100%0.01K391 512 1564K kmalloc-8 >> >>> >> >>> 170528 169359 99%0.25K 5329 32 42632K filp >> >>> >> >>> 158144 153508 97%0.06K 2471 64 9884K kmalloc-64 >> >>> >> >>> 149914 149365 99%0.09K 3259 46 13036K anon_vma >> >>> >> >>> 146640 143123 97%0.10K 3760 39 15040K buffer_head >> >>> >> >>> 130368 32791 25%0.09K 3104 42 12416K kmalloc-96 >> >>> >> >>> 129752 129752 100%0.07K 2317 56 9268K Acpi-Operand >> >>> >> >>> 105468 105106 99%0.04K 1034 102 4136K >> >>> selinux_inode_security >> >>> 73080 73080 100%0.13K 2436 30 9744K >> kernfs_node_cache >> >>> >> >>> 72360 70261 97%0.59K 1340 54 42880K inode_cache >> >>> >> >>> 71040 71040 100%0.12K 2220 32 8880K eventpoll_epi >> >>> >> >>> 68096 59262 87%0.02K266 256 1064K kmalloc-16 >> >>> >> >>> 53652 53652 100%0.04K526 102 2104K pde_opener >> >>> >> >>> 50496 31654 62%2.00K 3156 16100992K kmalloc-2048 >> >>> >> >>> 46242 46242 100%0.19K 1101 42 8808K cred_jar >> >>> >> >>> 44496 43013 96%0.66K927 48 29664K >> proc_inode_cache >> >>> >> >>> 44352 44352 100%0.06K693 64 2772K >> task_delay_info >> >>> >> >>> 43516 43471 99%0.69K946 46 30272K >> sock_inode_cache >> >>> >> >>> 37856 27626 72%1.00K 1183 32 37856K kmalloc-1024 >> >>> >> >>> 36736 36736 100%0.07K656 56 2624K eventpoll_pwq >> >>> >> >>> 34076 31282 91%0.57K 1217 28 19472K >> radix_tree_node >> >>> >> >>> 33660 30528 90%1.05K 1122 30 35904K >> ext4_inode_cache >> >>> >> >>> 32760 30959 94%0.19K780 42 6240K kmalloc-192 >> >>> >> >>> 32028 32028 100%0.04K314 102 1256K >> ext4_extent_status >> >>> >> >>> 30048 30048 100%0.25K939 32 7512K >> skbuff_head_cache >> >>> >> >>> 28736 28736 100%0.06K449 64 1796K fs_cache >> >>> >> >>> 24702 24702 100%0.69K537 46 17184K files_cache >> >>> >> >>> 23808 23808 100%0.66K496 48 15872K ovl_inode >> >>> >> >>> 23104 22945 99%0.12K722 32 2888K kmalloc-128 >> >>>
Re: iommu_iova slab eats too much memory
Well, that's the problem! I'm assuming the iommu kernel module is leaking memory. But I don't know why and how. Do you have any idea about it? Or any further information is needed? Robin Murphy 于 2020年4月24日周五 19:20写道： > On 2020-04-24 1:40 am, Bin wrote: > > Hello? anyone there? > > > > Bin 于2020年4月23日周四 下午5:14写道： > > > >> Forget to mention, I've already disabled the slab merge, so this is what > >> it is. > >> > >> Bin 于2020年4月23日周四 下午5:11写道： > >> > >>> Hey, guys: > >>> > >>> I'm running a batch of CoreOS boxes, the lsb_release is: > >>> > >>> ``` > >>> # cat /etc/lsb-release > >>> DISTRIB_ID="Container Linux by CoreOS" > >>> DISTRIB_RELEASE=2303.3.0 > >>> DISTRIB_CODENAME="Rhyolite" > >>> DISTRIB_DESCRIPTION="Container Linux by CoreOS 2303.3.0 (Rhyolite)" > >>> ``` > >>> > >>> ``` > >>> # uname -a > >>> Linux cloud-worker-25 4.19.86-coreos #1 SMP Mon Dec 2 20:13:38 -00 2019 > >>> x86_64 Intel(R) Xeon(R) CPU E5-2640 v2 @ 2.00GHz GenuineIntel GNU/Linux > >>> ``` > >>> Recently, I found my vms constently being killed due to OOM, and after > >>> digging into the problem, I finally realized that the kernel is leaking > >>> memory. > >>> > >>> Here's my slabinfo: > >>> > >>> Active / Total Objects (% used): 83818306 / 84191607 (99.6%) > >>> Active / Total Slabs (% used) : 1336293 / 1336293 (100.0%) > >>> Active / Total Caches (% used) : 152 / 217 (70.0%) > >>> Active / Total Size (% used) : 5828768.08K / 5996848.72K > (97.2%) > >>> Minimum / Average / Maximum Object : 0.01K / 0.07K / 23.25K > >>> > >>>OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME > >>> > >>> 80253888 80253888 100%0.06K 1253967 64 5015868K iommu_iova > > Do you really have a peak demand of ~80 million simultaneous DMA > buffers, or is some driver leaking DMA mappings? > > Robin. > > >>> 489472 489123 99%0.03K 3824 128 15296K kmalloc-32 > >>> > >>> 297444 271112 91%0.19K 7082 42 56656K dentry > >>> > >>> 254400 252784 99%0.06K 3975 64 15900K anon_vma_chain > >>> > >>> 222528 39255 17%0.50K 6954 32111264K kmalloc-512 > >>> > >>> 202482 201814 99%0.19K 4821 42 38568K vm_area_struct > >>> > >>> 200192 200192 100%0.01K391 512 1564K kmalloc-8 > >>> > >>> 170528 169359 99%0.25K 5329 32 42632K filp > >>> > >>> 158144 153508 97%0.06K 2471 64 9884K kmalloc-64 > >>> > >>> 149914 149365 99%0.09K 3259 46 13036K anon_vma > >>> > >>> 146640 143123 97%0.10K 3760 39 15040K buffer_head > >>> > >>> 130368 32791 25%0.09K 3104 42 12416K kmalloc-96 > >>> > >>> 129752 129752 100%0.07K 2317 56 9268K Acpi-Operand > >>> > >>> 105468 105106 99%0.04K 1034 102 4136K > >>> selinux_inode_security > >>> 73080 73080 100%0.13K 2436 30 9744K > kernfs_node_cache > >>> > >>> 72360 70261 97%0.59K 1340 54 42880K inode_cache > >>> > >>> 71040 71040 100%0.12K 2220 32 8880K eventpoll_epi > >>> > >>> 68096 59262 87%0.02K266 256 1064K kmalloc-16 > >>> > >>> 53652 53652 100%0.04K526 102 2104K pde_opener > >>> > >>> 50496 31654 62%2.00K 3156 16100992K kmalloc-2048 > >>> > >>> 46242 46242 100%0.19K 1101 42 8808K cred_jar > >>> > >>> 44496 43013 96%0.66K927 48 29664K > proc_inode_cache > >>> > >>> 44352 44352 100%0.06K693 64 2772K task_delay_info > >>> > >>> 43516 43471 99%0.69K946 46 30272K > sock_inode_cache > >>> > >>> 37856 27626 72%1.00K 1183 32 37856K kmalloc-1024 > >>> > >>> 36736 36736 100%0.07K656 56 2624K eventpoll_pwq > >>> > >>> 34076 31282 91%0.57K 1217 28 19472K radix_tree_node > >>> > >>> 33660 30528 90%1.05K 1122 30 35904K > ext4_inode_cache > >>> > >>> 32760 30959 94%0.19K780 42 6240K kmalloc-192 > >>> > >>> 32028 32028 100%0.04K314 102 1256K > ext4_extent_status > >>> > >>> 30048 30048 100%0.25K939 32 7512K > skbuff_head_cache > >>> > >>> 28736 28736 100%0.06K449 64 1796K fs_cache > >>> > >>> 24702 24702 100%0.69K537 46 17184K files_cache > >>> > >>> 23808 23808 100%0.66K496 48 15872K ovl_inode > >>> > >>> 23104 22945 99%0.12K722 32 2888K kmalloc-128 > >>> > >>> 22724 21307 93%0.69K494 46 15808K > shmem_inode_cache > >>> > >>> 21472 21472 100%0.12K671 32 2684K seq_file > >>> > >>> 19904 19904 100%1.00K622 32 19904K UNIX > >>> > >>> 17340 17340 100%1.06K578 30 18496K mm_struct > >>> > >>> 15980 15980 100%0.02K 94 170 376K avtab_node > >>> > >>> 14070
Re: iommu_iova slab eats too much memory
On 2020-04-24 1:40 am, Bin wrote: Hello? anyone there? Bin 于2020年4月23日周四 下午5:14写道： Forget to mention, I've already disabled the slab merge, so this is what it is. Bin 于2020年4月23日周四 下午5:11写道： Hey, guys: I'm running a batch of CoreOS boxes, the lsb_release is: ``` # cat /etc/lsb-release DISTRIB_ID="Container Linux by CoreOS" DISTRIB_RELEASE=2303.3.0 DISTRIB_CODENAME="Rhyolite" DISTRIB_DESCRIPTION="Container Linux by CoreOS 2303.3.0 (Rhyolite)" ``` ``` # uname -a Linux cloud-worker-25 4.19.86-coreos #1 SMP Mon Dec 2 20:13:38 -00 2019 x86_64 Intel(R) Xeon(R) CPU E5-2640 v2 @ 2.00GHz GenuineIntel GNU/Linux ``` Recently, I found my vms constently being killed due to OOM, and after digging into the problem, I finally realized that the kernel is leaking memory. Here's my slabinfo: Active / Total Objects (% used): 83818306 / 84191607 (99.6%) Active / Total Slabs (% used) : 1336293 / 1336293 (100.0%) Active / Total Caches (% used) : 152 / 217 (70.0%) Active / Total Size (% used) : 5828768.08K / 5996848.72K (97.2%) Minimum / Average / Maximum Object : 0.01K / 0.07K / 23.25K OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME 80253888 80253888 100%0.06K 1253967 64 5015868K iommu_iova Do you really have a peak demand of ~80 million simultaneous DMA buffers, or is some driver leaking DMA mappings? Robin. 489472 489123 99%0.03K 3824 128 15296K kmalloc-32 297444 271112 91%0.19K 7082 42 56656K dentry 254400 252784 99%0.06K 3975 64 15900K anon_vma_chain 222528 39255 17%0.50K 6954 32111264K kmalloc-512 202482 201814 99%0.19K 4821 42 38568K vm_area_struct 200192 200192 100%0.01K391 512 1564K kmalloc-8 170528 169359 99%0.25K 5329 32 42632K filp 158144 153508 97%0.06K 2471 64 9884K kmalloc-64 149914 149365 99%0.09K 3259 46 13036K anon_vma 146640 143123 97%0.10K 3760 39 15040K buffer_head 130368 32791 25%0.09K 3104 42 12416K kmalloc-96 129752 129752 100%0.07K 2317 56 9268K Acpi-Operand 105468 105106 99%0.04K 1034 102 4136K selinux_inode_security 73080 73080 100%0.13K 2436 30 9744K kernfs_node_cache 72360 70261 97%0.59K 1340 54 42880K inode_cache 71040 71040 100%0.12K 2220 32 8880K eventpoll_epi 68096 59262 87%0.02K266 256 1064K kmalloc-16 53652 53652 100%0.04K526 102 2104K pde_opener 50496 31654 62%2.00K 3156 16100992K kmalloc-2048 46242 46242 100%0.19K 1101 42 8808K cred_jar 44496 43013 96%0.66K927 48 29664K proc_inode_cache 44352 44352 100%0.06K693 64 2772K task_delay_info 43516 43471 99%0.69K946 46 30272K sock_inode_cache 37856 27626 72%1.00K 1183 32 37856K kmalloc-1024 36736 36736 100%0.07K656 56 2624K eventpoll_pwq 34076 31282 91%0.57K 1217 28 19472K radix_tree_node 33660 30528 90%1.05K 1122 30 35904K ext4_inode_cache 32760 30959 94%0.19K780 42 6240K kmalloc-192 32028 32028 100%0.04K314 102 1256K ext4_extent_status 30048 30048 100%0.25K939 32 7512K skbuff_head_cache 28736 28736 100%0.06K449 64 1796K fs_cache 24702 24702 100%0.69K537 46 17184K files_cache 23808 23808 100%0.66K496 48 15872K ovl_inode 23104 22945 99%0.12K722 32 2888K kmalloc-128 22724 21307 93%0.69K494 46 15808K shmem_inode_cache 21472 21472 100%0.12K671 32 2684K seq_file 19904 19904 100%1.00K622 32 19904K UNIX 17340 17340 100%1.06K578 30 18496K mm_struct 15980 15980 100%0.02K 94 170 376K avtab_node 14070 14070 100%1.06K469 30 15008K signal_cache 13248 13248 100%0.12K414 32 1656K pid 12128 11777 97%0.25K379 32 3032K kmalloc-256 11008 11008 100%0.02K 43 256 172K selinux_file_security 10812 10812 100%0.04K106 102 424K Acpi-Namespace These information shows that the 'iommu_iova' is the top memory consumer. In order to optimize the network performence of Openstack virtual machines, I enabled the vt-d feature in bios and sriov feature of Intel 82599 10G NIC. I'm assuming this is the root cause of this issue. Is there anything I can do to fix it? ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu ___ iommu mailing list
Re: iommu_iova slab eats too much memory
Hello? anyone there? Bin 于2020年4月23日周四 下午5:14写道： > Forget to mention, I've already disabled the slab merge, so this is what > it is. > > Bin 于2020年4月23日周四 下午5:11写道： > >> Hey, guys: >> >> I'm running a batch of CoreOS boxes, the lsb_release is: >> >> ``` >> # cat /etc/lsb-release >> DISTRIB_ID="Container Linux by CoreOS" >> DISTRIB_RELEASE=2303.3.0 >> DISTRIB_CODENAME="Rhyolite" >> DISTRIB_DESCRIPTION="Container Linux by CoreOS 2303.3.0 (Rhyolite)" >> ``` >> >> ``` >> # uname -a >> Linux cloud-worker-25 4.19.86-coreos #1 SMP Mon Dec 2 20:13:38 -00 2019 >> x86_64 Intel(R) Xeon(R) CPU E5-2640 v2 @ 2.00GHz GenuineIntel GNU/Linux >> ``` >> Recently, I found my vms constently being killed due to OOM, and after >> digging into the problem, I finally realized that the kernel is leaking >> memory. >> >> Here's my slabinfo: >> >> Active / Total Objects (% used): 83818306 / 84191607 (99.6%) >> Active / Total Slabs (% used) : 1336293 / 1336293 (100.0%) >> Active / Total Caches (% used) : 152 / 217 (70.0%) >> Active / Total Size (% used) : 5828768.08K / 5996848.72K (97.2%) >> Minimum / Average / Maximum Object : 0.01K / 0.07K / 23.25K >> >> OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME >> >> 80253888 80253888 100%0.06K 1253967 64 5015868K iommu_iova >> >> 489472 489123 99%0.03K 3824 128 15296K kmalloc-32 >> >> 297444 271112 91%0.19K 7082 42 56656K dentry >> >> 254400 252784 99%0.06K 3975 64 15900K anon_vma_chain >> >> 222528 39255 17%0.50K 6954 32111264K kmalloc-512 >> >> 202482 201814 99%0.19K 4821 42 38568K vm_area_struct >> >> 200192 200192 100%0.01K391 512 1564K kmalloc-8 >> >> 170528 169359 99%0.25K 5329 32 42632K filp >> >> 158144 153508 97%0.06K 2471 64 9884K kmalloc-64 >> >> 149914 149365 99%0.09K 3259 46 13036K anon_vma >> >> 146640 143123 97%0.10K 3760 39 15040K buffer_head >> >> 130368 32791 25%0.09K 3104 42 12416K kmalloc-96 >> >> 129752 129752 100%0.07K 2317 56 9268K Acpi-Operand >> >> 105468 105106 99%0.04K 1034 102 4136K >> selinux_inode_security >> 73080 73080 100%0.13K 2436 30 9744K kernfs_node_cache >> >> 72360 70261 97%0.59K 1340 54 42880K inode_cache >> >> 71040 71040 100%0.12K 2220 32 8880K eventpoll_epi >> >> 68096 59262 87%0.02K266 256 1064K kmalloc-16 >> >> 53652 53652 100%0.04K526 102 2104K pde_opener >> >> 50496 31654 62%2.00K 3156 16100992K kmalloc-2048 >> >> 46242 46242 100%0.19K 1101 42 8808K cred_jar >> >> 44496 43013 96%0.66K927 48 29664K proc_inode_cache >> >> 44352 44352 100%0.06K693 64 2772K task_delay_info >> >> 43516 43471 99%0.69K946 46 30272K sock_inode_cache >> >> 37856 27626 72%1.00K 1183 32 37856K kmalloc-1024 >> >> 36736 36736 100%0.07K656 56 2624K eventpoll_pwq >> >> 34076 31282 91%0.57K 1217 28 19472K radix_tree_node >> >> 33660 30528 90%1.05K 1122 30 35904K ext4_inode_cache >> >> 32760 30959 94%0.19K780 42 6240K kmalloc-192 >> >> 32028 32028 100%0.04K314 102 1256K ext4_extent_status >> >> 30048 30048 100%0.25K939 32 7512K skbuff_head_cache >> >> 28736 28736 100%0.06K449 64 1796K fs_cache >> >> 24702 24702 100%0.69K537 46 17184K files_cache >> >> 23808 23808 100%0.66K496 48 15872K ovl_inode >> >> 23104 22945 99%0.12K722 32 2888K kmalloc-128 >> >> 22724 21307 93%0.69K494 46 15808K shmem_inode_cache >> >> 21472 21472 100%0.12K671 32 2684K seq_file >> >> 19904 19904 100%1.00K622 32 19904K UNIX >> >> 17340 17340 100%1.06K578 30 18496K mm_struct >> >> 15980 15980 100%0.02K 94 170 376K avtab_node >> >> 14070 14070 100%1.06K469 30 15008K signal_cache >> >> 13248 13248 100%0.12K414 32 1656K pid >> >> 12128 11777 97%0.25K379 32 3032K kmalloc-256 >> >> 11008 11008 100%0.02K 43 256 172K >> selinux_file_security >> 10812 10812 100%0.04K106 102 424K Acpi-Namespace >> >> These information shows that the 'iommu_iova' is the top memory consumer. >> In order to optimize the network performence of Openstack virtual machines, >> I enabled the vt-d feature in bios and sriov feature of Intel 82599 10G >> NIC. I'm assuming this is the root cause of this issue. >> >> Is there anything I can do to fix it? >> > ___ iommu mailing list
Re: iommu_iova slab eats too much memory
Forget to mention, I've already disabled the slab merge, so this is what it is. Bin 于2020年4月23日周四 下午5:11写道： > Hey, guys: > > I'm running a batch of CoreOS boxes, the lsb_release is: > > ``` > # cat /etc/lsb-release > DISTRIB_ID="Container Linux by CoreOS" > DISTRIB_RELEASE=2303.3.0 > DISTRIB_CODENAME="Rhyolite" > DISTRIB_DESCRIPTION="Container Linux by CoreOS 2303.3.0 (Rhyolite)" > ``` > > ``` > # uname -a > Linux cloud-worker-25 4.19.86-coreos #1 SMP Mon Dec 2 20:13:38 -00 2019 > x86_64 Intel(R) Xeon(R) CPU E5-2640 v2 @ 2.00GHz GenuineIntel GNU/Linux > ``` > Recently, I found my vms constently being killed due to OOM, and after > digging into the problem, I finally realized that the kernel is leaking > memory. > > Here's my slabinfo: > > Active / Total Objects (% used): 83818306 / 84191607 (99.6%) > Active / Total Slabs (% used) : 1336293 / 1336293 (100.0%) > Active / Total Caches (% used) : 152 / 217 (70.0%) > Active / Total Size (% used) : 5828768.08K / 5996848.72K (97.2%) > Minimum / Average / Maximum Object : 0.01K / 0.07K / 23.25K > > OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME > > 80253888 80253888 100%0.06K 1253967 64 5015868K iommu_iova > > 489472 489123 99%0.03K 3824 128 15296K kmalloc-32 > > 297444 271112 91%0.19K 7082 42 56656K dentry > > 254400 252784 99%0.06K 3975 64 15900K anon_vma_chain > > 222528 39255 17%0.50K 6954 32111264K kmalloc-512 > > 202482 201814 99%0.19K 4821 42 38568K vm_area_struct > > 200192 200192 100%0.01K391 512 1564K kmalloc-8 > > 170528 169359 99%0.25K 5329 32 42632K filp > > 158144 153508 97%0.06K 2471 64 9884K kmalloc-64 > > 149914 149365 99%0.09K 3259 46 13036K anon_vma > > 146640 143123 97%0.10K 3760 39 15040K buffer_head > > 130368 32791 25%0.09K 3104 42 12416K kmalloc-96 > > 129752 129752 100%0.07K 2317 56 9268K Acpi-Operand > > 105468 105106 99%0.04K 1034 102 4136K > selinux_inode_security > 73080 73080 100%0.13K 2436 30 9744K kernfs_node_cache > > 72360 70261 97%0.59K 1340 54 42880K inode_cache > > 71040 71040 100%0.12K 2220 32 8880K eventpoll_epi > > 68096 59262 87%0.02K266 256 1064K kmalloc-16 > > 53652 53652 100%0.04K526 102 2104K pde_opener > > 50496 31654 62%2.00K 3156 16100992K kmalloc-2048 > > 46242 46242 100%0.19K 1101 42 8808K cred_jar > > 44496 43013 96%0.66K927 48 29664K proc_inode_cache > > 44352 44352 100%0.06K693 64 2772K task_delay_info > > 43516 43471 99%0.69K946 46 30272K sock_inode_cache > > 37856 27626 72%1.00K 1183 32 37856K kmalloc-1024 > > 36736 36736 100%0.07K656 56 2624K eventpoll_pwq > > 34076 31282 91%0.57K 1217 28 19472K radix_tree_node > > 33660 30528 90%1.05K 1122 30 35904K ext4_inode_cache > > 32760 30959 94%0.19K780 42 6240K kmalloc-192 > > 32028 32028 100%0.04K314 102 1256K ext4_extent_status > > 30048 30048 100%0.25K939 32 7512K skbuff_head_cache > > 28736 28736 100%0.06K449 64 1796K fs_cache > > 24702 24702 100%0.69K537 46 17184K files_cache > > 23808 23808 100%0.66K496 48 15872K ovl_inode > > 23104 22945 99%0.12K722 32 2888K kmalloc-128 > > 22724 21307 93%0.69K494 46 15808K shmem_inode_cache > > 21472 21472 100%0.12K671 32 2684K seq_file > > 19904 19904 100%1.00K622 32 19904K UNIX > > 17340 17340 100%1.06K578 30 18496K mm_struct > > 15980 15980 100%0.02K 94 170 376K avtab_node > > 14070 14070 100%1.06K469 30 15008K signal_cache > > 13248 13248 100%0.12K414 32 1656K pid > > 12128 11777 97%0.25K379 32 3032K kmalloc-256 > > 11008 11008 100%0.02K 43 256 172K > selinux_file_security > 10812 10812 100%0.04K106 102 424K Acpi-Namespace > > These information shows that the 'iommu_iova' is the top memory consumer. > In order to optimize the network performence of Openstack virtual machines, > I enabled the vt-d feature in bios and sriov feature of Intel 82599 10G > NIC. I'm assuming this is the root cause of this issue. > > Is there anything I can do to fix it? > ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
