Linaro-mm-sig

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Re: [Linaro-mm-sig] [PATCH] ASoC: fsl: imx-pcm-dma: Don't request dma channel in probe

by Lucas Stach

Hi Robin, Am Mittwoch, dem 14.04.2021 um 14:33 +0000 schrieb Robin Gong: > On 2020/05/20 17:43 Lucas Stach <l.stach(a)pengutronix.de> wrote: > > Am Mittwoch, den 20.05.2020, 16:20 +0800 schrieb Shengjiu Wang: > > > Hi > > > > > > On Tue, May 19, 2020 at 6:04 PM Lucas Stach <l.stach(a)pengutronix.de> > > wrote: > > > > Am Dienstag, den 19.05.2020, 17:41 +0800 schrieb Shengjiu Wang: > > > > > There are two requirements that we need to move the request of dma > > > > > channel from probe to open. > > > > > > > > How do you handle -EPROBE_DEFER return code from the channel request > > > > if you don't do it in probe? > > > > > > I use the dma_request_slave_channel or dma_request_channel instead of > > > dmaengine_pcm_request_chan_of. so there should be not -EPROBE_DEFER > > > return code. > > > > This is a pretty weak argument. The dmaengine device might probe after you > > try to get the channel. Using a function to request the channel that doesn't > > allow you to handle probe deferral is IMHO a bug and should be fixed, instead > > of building even more assumptions on top of it. > > > > > > > - When dma device binds with power-domains, the power will be > > > > > enabled when we request dma channel. If the request of dma channel > > > > > happen on probe, then the power-domains will be always enabled > > > > > after kernel boot up, which is not good for power saving, so we > > > > > need to move the request of dma channel to .open(); > > > > > > > > This is certainly something which could be fixed in the dmaengine > > > > driver. > > > > > > Dma driver always call the pm_runtime_get_sync in > > > device_alloc_chan_resources, the device_alloc_chan_resources is called > > > when channel is requested. so power is enabled on channel request. > > > > So why can't you fix the dmaengine driver to do that RPM call at a later time > > when the channel is actually going to be used? This will allow further power > > savings with other slave devices than the audio PCM. > Hi Lucas, > Thanks for your suggestion. I have tried to implement runtime autosuspend in > fsl-edma driver on i.mx8qm/qxp with delay time (2 sec) for this feature as below > (or you can refer to drivers/dma/qcom/hidma.c), and pm_runtime_get_sync/ > pm_runtime_put_autosuspend in all dmaengine driver interface like > device_alloc_chan_resources/device_prep_slave_sg/device_prep_dma_cyclic/ > device_tx_status... > > > pm_runtime_use_autosuspend(fsl_chan->dev); > pm_runtime_set_autosuspend_delay(fsl_chan->dev, 2000); > > That could resolve this audio case since the autosuspend could suspend runtime after > 2 seconds if there is no further dma transfer but only channel request(device_alloc_chan_resources). > But unfortunately, it cause another issue. As you know, on our i.mx8qm/qxp, > power domain done by scfw (drivers/firmware/imx/scu-pd.c) over mailbox: > imx_sc_pd_power()->imx_scu_call_rpc()-> imx_scu_ipc_write()->mbox_send_message() > which means have to 'waits for completion', meanwhile, some driver like tty will call dmaengine > interfaces in non-atomic case as below, > > static int uart_write(struct tty_struct *tty, const unsigned char *buf, int count) > { > ....... > port = uart_port_lock(state, flags); > ...... > __uart_start(tty); //call start_tx()->dmaengine_prep_slave_sg... > uart_port_unlock(port, flags); > return ret; > } > > Thus dma runtime resume may happen in that timing window and cause kernel alarm. > I'm not sure whether there are similar limitations on other driver subsystem. But for me, > It looks like the only way to resolve the contradiction between tty and scu-pd (hardware > limitation on i.mx8qm/qxp) is to give up autosuspend and keep pm_runtime_get_sync > only in device_alloc_chan_resources because request channel is a safe non-atomic phase. > Do you have any idea? Thanks in advance. If you look closely at the driver you used as an example (hidma.c) it looks like there is already something in there, which looks very much like what you need here: In hidma_issue_pending() the driver tries to get the device to runtime resume. If this doesn't work, maybe due to the power domain code not being able to be called in atomic context, the actual work of waking up the dma hardware and issuing the descriptor is shunted to a tasklet. If I'm reading this right, this is exactly what you need here to be able to call the dmaengine code from atomic context: try the rpm get and issue immediately when possible, otherwise shunt the work to a non- atomic context where you can deal with the requirements of scu-pd. Also you don't need the runtime resume in all of the functions you mentioned. From a quick look into the edma driver it looks like for example the prep_slave_dma() function only touches data structures in memory, so you don't actually need the device to be awake at that point. Only later in the flow when you write registers in the dma hardware and actually issue the transfer you need to wake the device from sleep. Regards, Lucas > > > > > > > > > > > > - With FE-BE case, if the dma channel is requested in probe, then > > > > > there will be below issue, which is caused by that the dma channel > > > > > will be requested duplicately > > > > > > > > Why is this requested a second time? Is this just some missing > > > > cleanup on a deferred probe path? > > > > > > Not relate with deferred probe. With DMA1->ASRC->DMA2->ESAI case, the > > > DMA1->ASRC->DMA2 is in FE, ESAI is in BE. When ESAI drvier probe, > > > DMA3 channel is created with ESAI's "dma:tx" (DMA3 channel > > > is not used in this FE-BE case). When FE-BE startup, DMA2 > > > channel is created, it needs the ESAI's "dma:tx", so below warning > > > comes out. > > > > > > > Regards, > > > > Lucas > > > > > > > > > [ 638.906268] sysfs: cannot create duplicate filename > > '/devices/soc0/soc/2000000.bus/2000000.spba-bus/2024000.esai/dma:tx' > > > > > [ 638.919061] CPU: 1 PID: 673 Comm: aplay Not tainted > > > > > 5.7.0-rc1-12956-gfc64b2585593 #287 [ 638.927113] Hardware name: > > > > > Freescale i.MX6 Quad/DualLite (Device Tree) [ 638.933690] > > > > > [<c0110dd8>] (unwind_backtrace) from [<c010b8ec>] > > > > > (show_stack+0x10/0x14) [ 638.941464] [<c010b8ec>] (show_stack) > > > > > from [<c0557fc0>] (dump_stack+0xe4/0x118) [ 638.948808] > > > > > [<c0557fc0>] (dump_stack) from [<c032aeb4>] > > > > > (sysfs_warn_dup+0x50/0x64) [ 638.956406] [<c032aeb4>] > > > > > (sysfs_warn_dup) from [<c032b1a8>] > > > > > (sysfs_do_create_link_sd+0xc8/0xd4) > > > > > [ 638.965134] [<c032b1a8>] (sysfs_do_create_link_sd) from > > > > > [<c05dc668>] (dma_request_chan+0xb0/0x210) [ 638.974120] > > > > > [<c05dc668>] (dma_request_chan) from [<c05dc7d0>] > > > > > (dma_request_slave_channel+0x8/0x14) > > > > > [ 638.983111] [<c05dc7d0>] (dma_request_slave_channel) from > > > > > [<c09d5548>] (fsl_asrc_dma_hw_params+0x1e0/0x438) > > > > > [ 638.992881] [<c09d5548>] (fsl_asrc_dma_hw_params) from > > > > > [<c09c1654>] (soc_pcm_hw_params+0x4a0/0x6a8) [ 639.001952] > > > > > [<c09c1654>] (soc_pcm_hw_params) from [<c09c39d4>] > > > > > (dpcm_fe_dai_hw_params+0x70/0xe4) [ 639.010765] [<c09c39d4>] > > > > > (dpcm_fe_dai_hw_params) from [<c099b274>] > > > > > (snd_pcm_hw_params+0x158/0x418) [ 639.019750] [<c099b274>] > > > > > (snd_pcm_hw_params) from [<c099c5a0>] > > (snd_pcm_ioctl+0x734/0x183c) [ 639.028129] [<c099c5a0>] (snd_pcm_ioctl) > > from [<c029ff94>] (ksys_ioctl+0x2ac/0xb98) [ 639.035812] [<c029ff94>] > > (ksys_ioctl) from [<c0100080>] (ret_fast_syscall+0x0/0x28) [ 639.043490] > > Exception stack(0xec529fa8 to 0xec529ff0) > > > > > [ 639.048565] 9fa0: bee84650 01321870 > > 00000004 c25c4111 bee84650 0002000f > > > > > [ 639.056766] 9fc0: bee84650 01321870 01321820 00000036 > > 00001f40 > > > > > 00000000 0002c2f8 00000003 [ 639.064964] 9fe0: b6f483fc bee8451c > > > > > b6ee2655 b6e1dcf8 [ 639.070339] fsl-esai-dai 2024000.esai: Cannot > > > > > create DMA dma:tx symlink > > > > > > > > > > Signed-off-by: Shengjiu Wang <shengjiu.wang(a)nxp.com> > > > > > --- > > > > > sound/soc/fsl/imx-pcm-dma.c | 173 > > > > > +++++++++++++++++++++++++++++++++--- > > > > > 1 file changed, 159 insertions(+), 14 deletions(-) > > > > > > > > > > diff --git a/sound/soc/fsl/imx-pcm-dma.c > > > > > b/sound/soc/fsl/imx-pcm-dma.c index 04a9bc749016..dae53b384df4 > > > > > 100644 > > > > > --- a/sound/soc/fsl/imx-pcm-dma.c > > > > > +++ b/sound/soc/fsl/imx-pcm-dma.c > > > > > @@ -11,6 +11,7 @@ > > > > > #include <linux/dmaengine.h> > > > > > #include <linux/types.h> > > > > > #include <linux/module.h> > > > > > +#include <linux/dma-mapping.h> > > > > > > > > > > #include <sound/core.h> > > > > > #include <sound/pcm.h> > > > > > @@ -29,24 +30,168 @@ static bool filter(struct dma_chan *chan, void > > *param) > > > > > return true; > > > > > } > > > > > > > > > > -static const struct snd_dmaengine_pcm_config > > imx_dmaengine_pcm_config = { > > > > > - .prepare_slave_config = > > snd_dmaengine_pcm_prepare_slave_config, > > > > > - .compat_filter_fn = filter, > > > > > -}; > > > > > +static int imx_pcm_hw_params(struct snd_soc_component > > *component, > > > > > + struct snd_pcm_substream *substream, > > > > > + struct snd_pcm_hw_params *params) { > > > > > + struct snd_pcm_runtime *runtime = substream->runtime; > > > > > + struct snd_soc_pcm_runtime *rtd = substream->private_data; > > > > > + struct snd_soc_dai *cpu_dai = asoc_rtd_to_cpu(rtd, 0); > > > > > + struct snd_dmaengine_dai_dma_data *dma_data; > > > > > + struct dma_slave_config config; > > > > > + struct dma_chan *chan; > > > > > + int ret = 0; > > > > > > > > > > -int imx_pcm_dma_init(struct platform_device *pdev, size_t size) > > > > > + snd_pcm_set_runtime_buffer(substream, > > &substream->dma_buffer); > > > > > + runtime->dma_bytes = params_buffer_bytes(params); > > > > > + > > > > > + chan = snd_dmaengine_pcm_get_chan(substream); > > > > > + if (!chan) > > > > > + return -EINVAL; > > > > > + > > > > > + ret = snd_hwparams_to_dma_slave_config(substream, params, > > &config); > > > > > + if (ret) > > > > > + return ret; > > > > > + > > > > > + dma_data = snd_soc_dai_get_dma_data(cpu_dai, substream); > > > > > + if (!dma_data) > > > > > + return -EINVAL; > > > > > + > > > > > + snd_dmaengine_pcm_set_config_from_dai_data(substream, > > > > > + dma_data, > > > > > + &config); > > > > > + return dmaengine_slave_config(chan, &config); } > > > > > + > > > > > +static int imx_pcm_hw_free(struct snd_soc_component *component, > > > > > + struct snd_pcm_substream *substream) > > > > > { > > > > > - struct snd_dmaengine_pcm_config *config; > > > > > + snd_pcm_set_runtime_buffer(substream, NULL); > > > > > + return 0; > > > > > +} > > > > > + > > > > > +static snd_pcm_uframes_t imx_pcm_pointer(struct snd_soc_component > > *component, > > > > > + struct snd_pcm_substream > > > > > +*substream) { > > > > > + return snd_dmaengine_pcm_pointer(substream); > > > > > +} > > > > > + > > > > > +static int imx_pcm_trigger(struct snd_soc_component *component, > > > > > + struct snd_pcm_substream *substream, int > > > > > +cmd) { > > > > > + return snd_dmaengine_pcm_trigger(substream, cmd); } > > > > > + > > > > > +static int imx_pcm_open(struct snd_soc_component *component, > > > > > + struct snd_pcm_substream *substream) { > > > > > + struct snd_soc_pcm_runtime *rtd = substream->private_data; > > > > > + bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK; > > > > > + struct snd_soc_dai *cpu_dai = asoc_rtd_to_cpu(rtd, 0); > > > > > + struct snd_dmaengine_dai_dma_data *dma_data; > > > > > + struct device *dev = component->dev; > > > > > + struct snd_pcm_hardware hw; > > > > > + struct dma_chan *chan; > > > > > + int ret; > > > > > + > > > > > + ret = snd_pcm_hw_constraint_integer(substream->runtime, > > > > > + > > SNDRV_PCM_HW_PARAM_PERIODS); > > > > > + if (ret < 0) { > > > > > + dev_err(dev, "failed to set pcm hw params periods\n"); > > > > > + return ret; > > > > > + } > > > > > + > > > > > + dma_data = snd_soc_dai_get_dma_data(cpu_dai, substream); > > > > > + if (!dma_data) > > > > > + return -EINVAL; > > > > > + > > > > > + chan = dma_request_slave_channel(cpu_dai->dev, tx ? "tx" : "rx"); > > > > > + if (!chan) { > > > > > + /* Try to request channel using compat_filter_fn */ > > > > > + chan = snd_dmaengine_pcm_request_channel(filter, > > > > > + > > dma_data->filter_data); > > > > > + if (!chan) > > > > > + return -ENXIO; > > > > > + } > > > > > > > > > > - config = devm_kzalloc(&pdev->dev, > > > > > - sizeof(struct snd_dmaengine_pcm_config), > > GFP_KERNEL); > > > > > - if (!config) > > > > > - return -ENOMEM; > > > > > - *config = imx_dmaengine_pcm_config; > > > > > + ret = snd_dmaengine_pcm_open(substream, chan); > > > > > + if (ret) > > > > > + goto pcm_open_fail; > > > > > > > > > > - return devm_snd_dmaengine_pcm_register(&pdev->dev, > > > > > - config, > > > > > - SND_DMAENGINE_PCM_FLAG_COMPAT); > > > > > + memset(&hw, 0, sizeof(hw)); > > > > > + hw.info = SNDRV_PCM_INFO_MMAP | > > SNDRV_PCM_INFO_MMAP_VALID | > > > > > + SNDRV_PCM_INFO_INTERLEAVED; > > > > > + hw.periods_min = 2; > > > > > + hw.periods_max = UINT_MAX; > > > > > + hw.period_bytes_min = 256; > > > > > + hw.period_bytes_max = > > dma_get_max_seg_size(chan->device->dev); > > > > > + hw.buffer_bytes_max = IMX_DEFAULT_DMABUF_SIZE; > > > > > + hw.fifo_size = dma_data->fifo_size; > > > > > + > > > > > + /* Refine the hw according to caps of DMA. */ > > > > > + ret = snd_dmaengine_pcm_refine_runtime_hwparams(substream, > > > > > + > > dma_data, > > > > > + &hw, > > > > > + chan); > > > > > + if (ret < 0) > > > > > + goto refine_runtime_hwparams_fail; > > > > > + > > > > > + snd_soc_set_runtime_hwparams(substream, &hw); > > > > > + > > > > > + /* Support allocate memory from IRAM */ > > > > > + ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV_IRAM, > > > > > + chan->device->dev, > > > > > + hw.buffer_bytes_max, > > > > > + &substream->dma_buffer); > > > > > + if (ret < 0) > > > > > + goto alloc_pagas_fail; > > > > > + > > > > > + return 0; > > > > > + > > > > > +alloc_pagas_fail: > > > > > +refine_runtime_hwparams_fail: > > > > > + snd_dmaengine_pcm_close(substream); > > > > > +pcm_open_fail: > > > > > + dma_release_channel(chan); > > > > > + > > > > > + return ret; > > > > > +} > > > > > + > > > > > +static int imx_pcm_close(struct snd_soc_component *component, > > > > > + struct snd_pcm_substream *substream) { > > > > > + if (substream) { > > > > > + snd_dma_free_pages(&substream->dma_buffer); > > > > > + substream->dma_buffer.area = NULL; > > > > > + substream->dma_buffer.addr = 0; > > > > > + } > > > > > + > > > > > + return snd_dmaengine_pcm_close_release_chan(substream); > > > > > +} > > > > > + > > > > > +static int imx_pcm_new(struct snd_soc_component *component, > > > > > + struct snd_soc_pcm_runtime *rtd) { > > > > > + struct snd_card *card = rtd->card->snd_card; > > > > > + > > > > > + return dma_coerce_mask_and_coherent(card->dev, > > > > > +DMA_BIT_MASK(32)); } > > > > > + > > > > > +static const struct snd_soc_component_driver imx_pcm_component = { > > > > > + .name = "imx-pcm-dma", > > > > > + .pcm_construct = imx_pcm_new, > > > > > + .open = imx_pcm_open, > > > > > + .close = imx_pcm_close, > > > > > + .hw_params = imx_pcm_hw_params, > > > > > + .hw_free = imx_pcm_hw_free, > > > > > + .trigger = imx_pcm_trigger, > > > > > + .pointer = imx_pcm_pointer, > > > > > +}; > > > > > + > > > > > +int imx_pcm_dma_init(struct platform_device *pdev, size_t size) { > > > > > + return devm_snd_soc_register_component(&pdev->dev, > > > > > + > > &imx_pcm_component, > > > > > +NULL, 0); > > > > > } > > > > > EXPORT_SYMBOL_GPL(imx_pcm_dma_init); > > > > > >

4 years, 7 months

[PATCH 1/3] dma-buf: Require VM_PFNMAP vma for mmap

by Daniel Vetter

tldr; DMA buffers aren't normal memory, expecting that you can use them like that (like calling get_user_pages works, or that they're accounting like any other normal memory) cannot be guaranteed. Since some userspace only runs on integrated devices, where all buffers are actually all resident system memory, there's a huge temptation to assume that a struct page is always present and useable like for any more pagecache backed mmap. This has the potential to result in a uapi nightmare. To stop this gap require that DMA buffer mmaps are VM_PFNMAP, which blocks get_user_pages and all the other struct page based infrastructure for everyone. In spirit this is the uapi counterpart to the kernel-internal CONFIG_DMABUF_DEBUG. Motivated by a recent patch which wanted to swich the system dma-buf heap to vm_insert_page instead of vm_insert_pfn. v2: Jason brought up that we also want to guarantee that all ptes have the pte_special flag set, to catch fast get_user_pages (on architectures that support this). Allowing VM_MIXEDMAP (like VM_SPECIAL does) would still allow vm_insert_page, but limiting to VM_PFNMAP will catch that. >From auditing the various functions to insert pfn pte entires (vm_insert_pfn_prot, remap_pfn_range and all it's callers like dma_mmap_wc) it looks like VM_PFNMAP is already required anyway, so this should be the correct flag to check for. References: https://lore.kernel.org/lkml/CAKMK7uHi+mG0z0HUmNt13QCCvutuRVjpcR0NjRL12k-Wb… Acked-by: Christian König <christian.koenig(a)amd.com> Cc: Jason Gunthorpe <jgg(a)ziepe.ca> Cc: Suren Baghdasaryan <surenb(a)google.com> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: John Stultz <john.stultz(a)linaro.org> Signed-off-by: Daniel Vetter <daniel.vetter(a)intel.com> Cc: Sumit Semwal <sumit.semwal(a)linaro.org> Cc: "Christian König" <christian.koenig(a)amd.com> Cc: linux-media(a)vger.kernel.org Cc: linaro-mm-sig(a)lists.linaro.org --- drivers/dma-buf/dma-buf.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index f264b70c383e..06cb1d2e9fdc 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -127,6 +127,7 @@ static struct file_system_type dma_buf_fs_type = { static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) { struct dma_buf *dmabuf; + int ret; if (!is_dma_buf_file(file)) return -EINVAL; @@ -142,7 +143,11 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) dmabuf->size >> PAGE_SHIFT) return -EINVAL; - return dmabuf->ops->mmap(dmabuf, vma); + ret = dmabuf->ops->mmap(dmabuf, vma); + + WARN_ON(!(vma->vm_flags & VM_PFNMAP)); + + return ret; } static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence) @@ -1244,6 +1249,8 @@ EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access); int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, unsigned long pgoff) { + int ret; + if (WARN_ON(!dmabuf || !vma)) return -EINVAL; @@ -1264,7 +1271,11 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, vma_set_file(vma, dmabuf->file); vma->vm_pgoff = pgoff; - return dmabuf->ops->mmap(dmabuf, vma); + ret = dmabuf->ops->mmap(dmabuf, vma); + + WARN_ON(!(vma->vm_flags & VM_PFNMAP)); + + return ret; } EXPORT_SYMBOL_GPL(dma_buf_mmap); -- 2.31.0

4 years, 7 months

Re: [Linaro-mm-sig] [PATCH RFC 1/3] fpga: region: Add fpga-region property 'fpga-config-from-dmabuf'

by Rob Herring

On Fri, Apr 02, 2021 at 02:39:31PM +0530, Nava kishore Manne wrote: > Add "fpga-config-from-dmabuf" property to allow the bitstream > configuration from pre-allocated dma-buffer. > > Signed-off-by: Nava kishore Manne <nava.manne(a)xilinx.com> > --- > Documentation/devicetree/bindings/fpga/fpga-region.txt | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/Documentation/devicetree/bindings/fpga/fpga-region.txt b/Documentation/devicetree/bindings/fpga/fpga-region.txt > index 969ca53bb65e..c573cf258d60 100644 > --- a/Documentation/devicetree/bindings/fpga/fpga-region.txt > +++ b/Documentation/devicetree/bindings/fpga/fpga-region.txt > @@ -177,6 +177,8 @@ Optional properties: > it indicates that the FPGA has already been programmed with this image. > If this property is in an overlay targeting a FPGA region, it is a > request to program the FPGA with that image. > +- fpga-config-from-dmabuf : boolean, set if the FPGA configured done from the > + pre-allocated dma-buffer. Sounds like an implementation detail of the OS. Doesn't belong in DT. Rob > - fpga-bridges : should contain a list of phandles to FPGA Bridges that must be > controlled during FPGA programming along with the parent FPGA bridge. > This property is optional if the FPGA Manager handles the bridges. > -- > 2.18.0 >

4 years, 7 months

[PATCH] drm/syncobj: use newly allocated stub fences

by David Stevens

From: David Stevens <stevensd(a)chromium.org> Allocate a new private stub fence in drm_syncobj_assign_null_handle, instead of using a static stub fence. When userspace creates a fence with DRM_SYNCOBJ_CREATE_SIGNALED or when userspace signals a fence via DRM_IOCTL_SYNCOBJ_SIGNAL, the timestamp obtained when the fence is exported and queried with SYNC_IOC_FILE_INFO should match when the fence's status was changed from the perspective of userspace, which is during the respective ioctl. When a static stub fence started being used in by these ioctls, this behavior changed. Instead, the timestamp returned by SYNC_IOC_FILE_INFO became the first time anything used the static stub fence, which has no meaning to userspace. Signed-off-by: David Stevens <stevensd(a)chromium.org> --- drivers/dma-buf/dma-fence.c | 33 ++++++++++++++++++++++++++++++++- drivers/gpu/drm/drm_syncobj.c | 28 ++++++++++++++++++++-------- include/linux/dma-fence.h | 1 + 3 files changed, 53 insertions(+), 9 deletions(-) diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index d64fc03929be..6081eb962490 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -26,6 +26,11 @@ EXPORT_TRACEPOINT_SYMBOL(dma_fence_signaled); static DEFINE_SPINLOCK(dma_fence_stub_lock); static struct dma_fence dma_fence_stub; +struct drm_fence_private_stub { + struct dma_fence base; + spinlock_t lock; +}; + /* * fence context counter: each execution context should have its own * fence context, this allows checking if fences belong to the same @@ -123,7 +128,9 @@ static const struct dma_fence_ops dma_fence_stub_ops = { /** * dma_fence_get_stub - return a signaled fence * - * Return a stub fence which is already signaled. + * Return a stub fence which is already signaled. The fence's + * timestamp corresponds to the first time after boot this + * function is called. */ struct dma_fence *dma_fence_get_stub(void) { @@ -141,6 +148,30 @@ struct dma_fence *dma_fence_get_stub(void) } EXPORT_SYMBOL(dma_fence_get_stub); +/** + * dma_fence_allocate_private_stub - return a private, signaled fence + * + * Return a newly allocated and signaled stub fence. + */ +struct dma_fence *dma_fence_allocate_private_stub(void) +{ + struct drm_fence_private_stub *fence; + + fence = kzalloc(sizeof(*fence), GFP_KERNEL); + if (fence == NULL) + return ERR_PTR(-ENOMEM); + + spin_lock_init(&fence->lock); + dma_fence_init(&fence->base, + &dma_fence_stub_ops, + &fence->lock, + 0, 0); + dma_fence_signal(&fence->base); + + return &fence->base; +} +EXPORT_SYMBOL(dma_fence_allocate_private_stub); + /** * dma_fence_context_alloc - allocate an array of fence contexts * @num: amount of contexts to allocate diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index 349146049849..c6125e57ae37 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -350,12 +350,15 @@ EXPORT_SYMBOL(drm_syncobj_replace_fence); * * Assign a already signaled stub fence to the sync object. */ -static void drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) +static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) { - struct dma_fence *fence = dma_fence_get_stub(); + struct dma_fence *fence = dma_fence_allocate_private_stub(); + if (IS_ERR(fence)) + return PTR_ERR(fence); - drm_syncobj_replace_fence(syncobj, fence); - dma_fence_put(fence); + drm_syncobj_replace_fence(syncobj, fence); + dma_fence_put(fence); + return 0; } /* 5s default for wait submission */ @@ -469,6 +472,7 @@ EXPORT_SYMBOL(drm_syncobj_free); int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, struct dma_fence *fence) { + int ret; struct drm_syncobj *syncobj; syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL); @@ -479,8 +483,13 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, INIT_LIST_HEAD(&syncobj->cb_list); spin_lock_init(&syncobj->lock); - if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) - drm_syncobj_assign_null_handle(syncobj); + if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) { + ret = drm_syncobj_assign_null_handle(syncobj); + if (ret < 0) { + drm_syncobj_put(syncobj); + return ret; + } + } if (fence) drm_syncobj_replace_fence(syncobj, fence); @@ -1322,8 +1331,11 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data, if (ret < 0) return ret; - for (i = 0; i < args->count_handles; i++) - drm_syncobj_assign_null_handle(syncobjs[i]); + for (i = 0; i < args->count_handles; i++) { + ret = drm_syncobj_assign_null_handle(syncobjs[i]); + if (ret < 0) + break; + } drm_syncobj_array_free(syncobjs, args->count_handles); diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 9f12efaaa93a..6ffb4b2c6371 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -587,6 +587,7 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr) } struct dma_fence *dma_fence_get_stub(void); +struct dma_fence *dma_fence_allocate_private_stub(void); u64 dma_fence_context_alloc(unsigned num); #define DMA_FENCE_TRACE(f, fmt, args...) \ -- 2.31.0.208.g409f899ff0-goog

4 years, 7 months

[PATCH v3] drm/syncobj: use newly allocated stub fences

by David Stevens

From: David Stevens <stevensd(a)chromium.org> Allocate a new private stub fence in drm_syncobj_assign_null_handle, instead of using a static stub fence. When userspace creates a fence with DRM_SYNCOBJ_CREATE_SIGNALED or when userspace signals a fence via DRM_IOCTL_SYNCOBJ_SIGNAL, the timestamp obtained when the fence is exported and queried with SYNC_IOC_FILE_INFO should match when the fence's status was changed from the perspective of userspace, which is during the respective ioctl. When a static stub fence started being used in by these ioctls, this behavior changed. Instead, the timestamp returned by SYNC_IOC_FILE_INFO became the first time anything used the static stub fence, which has no meaning to userspace. Signed-off-by: David Stevens <stevensd(a)chromium.org> --- v2 -> v3: - reuse the static stub spinlock v1 -> v2: - checkpatch style fixes drivers/dma-buf/dma-fence.c | 27 ++++++++++++++++++++++++++- drivers/gpu/drm/drm_syncobj.c | 25 +++++++++++++++++++------ include/linux/dma-fence.h | 1 + 3 files changed, 46 insertions(+), 7 deletions(-) diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index d64fc03929be..ce0f5eff575d 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -123,7 +123,9 @@ static const struct dma_fence_ops dma_fence_stub_ops = { /** * dma_fence_get_stub - return a signaled fence * - * Return a stub fence which is already signaled. + * Return a stub fence which is already signaled. The fence's + * timestamp corresponds to the first time after boot this + * function is called. */ struct dma_fence *dma_fence_get_stub(void) { @@ -141,6 +143,29 @@ struct dma_fence *dma_fence_get_stub(void) } EXPORT_SYMBOL(dma_fence_get_stub); +/** + * dma_fence_allocate_private_stub - return a private, signaled fence + * + * Return a newly allocated and signaled stub fence. + */ +struct dma_fence *dma_fence_allocate_private_stub(void) +{ + struct dma_fence *fence; + + fence = kzalloc(sizeof(*fence), GFP_KERNEL); + if (fence == NULL) + return ERR_PTR(-ENOMEM); + + dma_fence_init(fence, + &dma_fence_stub_ops, + &dma_fence_stub_lock, + 0, 0); + dma_fence_signal(fence); + + return fence; +} +EXPORT_SYMBOL(dma_fence_allocate_private_stub); + /** * dma_fence_context_alloc - allocate an array of fence contexts * @num: amount of contexts to allocate diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index 349146049849..a54aa850d143 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -350,12 +350,16 @@ EXPORT_SYMBOL(drm_syncobj_replace_fence); * * Assign a already signaled stub fence to the sync object. */ -static void drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) +static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) { - struct dma_fence *fence = dma_fence_get_stub(); + struct dma_fence *fence = dma_fence_allocate_private_stub(); + + if (IS_ERR(fence)) + return PTR_ERR(fence); drm_syncobj_replace_fence(syncobj, fence); dma_fence_put(fence); + return 0; } /* 5s default for wait submission */ @@ -469,6 +473,7 @@ EXPORT_SYMBOL(drm_syncobj_free); int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, struct dma_fence *fence) { + int ret; struct drm_syncobj *syncobj; syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL); @@ -479,8 +484,13 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, INIT_LIST_HEAD(&syncobj->cb_list); spin_lock_init(&syncobj->lock); - if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) - drm_syncobj_assign_null_handle(syncobj); + if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) { + ret = drm_syncobj_assign_null_handle(syncobj); + if (ret < 0) { + drm_syncobj_put(syncobj); + return ret; + } + } if (fence) drm_syncobj_replace_fence(syncobj, fence); @@ -1322,8 +1332,11 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data, if (ret < 0) return ret; - for (i = 0; i < args->count_handles; i++) - drm_syncobj_assign_null_handle(syncobjs[i]); + for (i = 0; i < args->count_handles; i++) { + ret = drm_syncobj_assign_null_handle(syncobjs[i]); + if (ret < 0) + break; + } drm_syncobj_array_free(syncobjs, args->count_handles); diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 9f12efaaa93a..6ffb4b2c6371 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -587,6 +587,7 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr) } struct dma_fence *dma_fence_get_stub(void); +struct dma_fence *dma_fence_allocate_private_stub(void); u64 dma_fence_context_alloc(unsigned num); #define DMA_FENCE_TRACE(f, fmt, args...) \ -- 2.31.0.208.g409f899ff0-goog

4 years, 7 months

[PATCH v2] drm/syncobj: use newly allocated stub fences

by David Stevens

From: David Stevens <stevensd(a)chromium.org> Allocate a new private stub fence in drm_syncobj_assign_null_handle, instead of using a static stub fence. When userspace creates a fence with DRM_SYNCOBJ_CREATE_SIGNALED or when userspace signals a fence via DRM_IOCTL_SYNCOBJ_SIGNAL, the timestamp obtained when the fence is exported and queried with SYNC_IOC_FILE_INFO should match when the fence's status was changed from the perspective of userspace, which is during the respective ioctl. When a static stub fence started being used in by these ioctls, this behavior changed. Instead, the timestamp returned by SYNC_IOC_FILE_INFO became the first time anything used the static stub fence, which has no meaning to userspace. Signed-off-by: David Stevens <stevensd(a)chromium.org> --- v1 -> v2: - checkpatch style fixes drivers/dma-buf/dma-fence.c | 33 ++++++++++++++++++++++++++++++++- drivers/gpu/drm/drm_syncobj.c | 25 +++++++++++++++++++------ include/linux/dma-fence.h | 1 + 3 files changed, 52 insertions(+), 7 deletions(-) diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index d64fc03929be..6081eb962490 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -26,6 +26,11 @@ EXPORT_TRACEPOINT_SYMBOL(dma_fence_signaled); static DEFINE_SPINLOCK(dma_fence_stub_lock); static struct dma_fence dma_fence_stub; +struct drm_fence_private_stub { + struct dma_fence base; + spinlock_t lock; +}; + /* * fence context counter: each execution context should have its own * fence context, this allows checking if fences belong to the same @@ -123,7 +128,9 @@ static const struct dma_fence_ops dma_fence_stub_ops = { /** * dma_fence_get_stub - return a signaled fence * - * Return a stub fence which is already signaled. + * Return a stub fence which is already signaled. The fence's + * timestamp corresponds to the first time after boot this + * function is called. */ struct dma_fence *dma_fence_get_stub(void) { @@ -141,6 +148,30 @@ struct dma_fence *dma_fence_get_stub(void) } EXPORT_SYMBOL(dma_fence_get_stub); +/** + * dma_fence_allocate_private_stub - return a private, signaled fence + * + * Return a newly allocated and signaled stub fence. + */ +struct dma_fence *dma_fence_allocate_private_stub(void) +{ + struct drm_fence_private_stub *fence; + + fence = kzalloc(sizeof(*fence), GFP_KERNEL); + if (fence == NULL) + return ERR_PTR(-ENOMEM); + + spin_lock_init(&fence->lock); + dma_fence_init(&fence->base, + &dma_fence_stub_ops, + &fence->lock, + 0, 0); + dma_fence_signal(&fence->base); + + return &fence->base; +} +EXPORT_SYMBOL(dma_fence_allocate_private_stub); + /** * dma_fence_context_alloc - allocate an array of fence contexts * @num: amount of contexts to allocate diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index 349146049849..a54aa850d143 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -350,12 +350,16 @@ EXPORT_SYMBOL(drm_syncobj_replace_fence); * * Assign a already signaled stub fence to the sync object. */ -static void drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) +static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) { - struct dma_fence *fence = dma_fence_get_stub(); + struct dma_fence *fence = dma_fence_allocate_private_stub(); + + if (IS_ERR(fence)) + return PTR_ERR(fence); drm_syncobj_replace_fence(syncobj, fence); dma_fence_put(fence); + return 0; } /* 5s default for wait submission */ @@ -469,6 +473,7 @@ EXPORT_SYMBOL(drm_syncobj_free); int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, struct dma_fence *fence) { + int ret; struct drm_syncobj *syncobj; syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL); @@ -479,8 +484,13 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, INIT_LIST_HEAD(&syncobj->cb_list); spin_lock_init(&syncobj->lock); - if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) - drm_syncobj_assign_null_handle(syncobj); + if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) { + ret = drm_syncobj_assign_null_handle(syncobj); + if (ret < 0) { + drm_syncobj_put(syncobj); + return ret; + } + } if (fence) drm_syncobj_replace_fence(syncobj, fence); @@ -1322,8 +1332,11 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data, if (ret < 0) return ret; - for (i = 0; i < args->count_handles; i++) - drm_syncobj_assign_null_handle(syncobjs[i]); + for (i = 0; i < args->count_handles; i++) { + ret = drm_syncobj_assign_null_handle(syncobjs[i]); + if (ret < 0) + break; + } drm_syncobj_array_free(syncobjs, args->count_handles); diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 9f12efaaa93a..6ffb4b2c6371 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -587,6 +587,7 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr) } struct dma_fence *dma_fence_get_stub(void); +struct dma_fence *dma_fence_allocate_private_stub(void); u64 dma_fence_context_alloc(unsigned num); #define DMA_FENCE_TRACE(f, fmt, args...) \ -- 2.31.0.208.g409f899ff0-goog

4 years, 7 months

[PATCH] Revert "drm/syncobj: use dma_fence_get_stub"

by David Stevens

From: David Stevens <stevensd(a)chromium.org> This reverts commit 86bbd89d5da66fe760049ad3f04adc407ec0c4d6. Using the singleton stub fence in drm_syncobj_assign_null_handle means that all syncobjs created in an already signaled state or any syncobjs signaled by userspace will reference the singleton fence when exported to a sync_file. If those sync_files are queried with SYNC_IOC_FILE_INFO, then the timestamp_ns value returned will correspond to whenever the singleton stub fence was first initialized. This can break the ability of userspace to use timestamps of these fences, as the singleton stub fence's timestamp bears no relationship to any meaningful event. Signed-off-by: David Stevens <stevensd(a)chromium.org> --- drivers/gpu/drm/drm_syncobj.c | 58 ++++++++++++++++++++++++++--------- 1 file changed, 44 insertions(+), 14 deletions(-) diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index 349146049849..7cc11f1a83f4 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -211,6 +211,21 @@ struct syncobj_wait_entry { static void syncobj_wait_syncobj_func(struct drm_syncobj *syncobj, struct syncobj_wait_entry *wait); +struct drm_syncobj_stub_fence { + struct dma_fence base; + spinlock_t lock; +}; + +static const char *drm_syncobj_stub_fence_get_name(struct dma_fence *fence) +{ + return "syncobjstub"; +} + +static const struct dma_fence_ops drm_syncobj_stub_fence_ops = { + .get_driver_name = drm_syncobj_stub_fence_get_name, + .get_timeline_name = drm_syncobj_stub_fence_get_name, +}; + /** * drm_syncobj_find - lookup and reference a sync object. * @file_private: drm file private pointer @@ -344,18 +359,24 @@ void drm_syncobj_replace_fence(struct drm_syncobj *syncobj, } EXPORT_SYMBOL(drm_syncobj_replace_fence); -/** - * drm_syncobj_assign_null_handle - assign a stub fence to the sync object - * @syncobj: sync object to assign the fence on - * - * Assign a already signaled stub fence to the sync object. - */ -static void drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) +static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj) { - struct dma_fence *fence = dma_fence_get_stub(); + struct drm_syncobj_stub_fence *fence; - drm_syncobj_replace_fence(syncobj, fence); - dma_fence_put(fence); + fence = kzalloc(sizeof(*fence), GFP_KERNEL); + if (fence == NULL) + return -ENOMEM; + + spin_lock_init(&fence->lock); + dma_fence_init(&fence->base, &drm_syncobj_stub_fence_ops, + &fence->lock, 0, 0); + dma_fence_signal(&fence->base); + + drm_syncobj_replace_fence(syncobj, &fence->base); + + dma_fence_put(&fence->base); + + return 0; } /* 5s default for wait submission */ @@ -469,6 +490,7 @@ EXPORT_SYMBOL(drm_syncobj_free); int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, struct dma_fence *fence) { + int ret; struct drm_syncobj *syncobj; syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL); @@ -479,8 +501,13 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, INIT_LIST_HEAD(&syncobj->cb_list); spin_lock_init(&syncobj->lock); - if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) - drm_syncobj_assign_null_handle(syncobj); + if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) { + ret = drm_syncobj_assign_null_handle(syncobj); + if (ret < 0) { + drm_syncobj_put(syncobj); + return ret; + } + } if (fence) drm_syncobj_replace_fence(syncobj, fence); @@ -1322,8 +1349,11 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data, if (ret < 0) return ret; - for (i = 0; i < args->count_handles; i++) - drm_syncobj_assign_null_handle(syncobjs[i]); + for (i = 0; i < args->count_handles; i++) { + ret = drm_syncobj_assign_null_handle(syncobjs[i]); + if (ret < 0) + break; + } drm_syncobj_array_free(syncobjs, args->count_handles); -- 2.31.0.208.g409f899ff0-goog

4 years, 7 months

Re: [Linaro-mm-sig] [PATCH] drm/amdgpu: Fix a potential sdma invalid access

by Christian König

Hi Qu, Am 02.04.21 um 05:18 schrieb Qu Huang: > Before dma_resv_lock(bo->base.resv, NULL) in amdgpu_bo_release_notify(), > the bo->base.resv lock may be held by ttm_mem_evict_first(), That can't happen since when bo_release_notify is called the BO has not more references and is therefore deleted. And we never evict a deleted BO, we just wait for it to become idle. Regards, Christian. > and the VRAM mem will be evicted, mem region was replaced > by Gtt mem region. amdgpu_bo_release_notify() will then > hold the bo->base.resv lock, and SDMA will get an invalid > address in amdgpu_fill_buffer(), resulting in a VMFAULT > or memory corruption. > > To avoid it, we have to hold bo->base.resv lock first, and > check whether the mem.mem_type is TTM_PL_VRAM. > > Signed-off-by: Qu Huang <jinsdb(a)126.com> > --- > drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c > index 4b29b82..8018574 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c > @@ -1300,12 +1300,16 @@ void amdgpu_bo_release_notify(struct ttm_buffer_object *bo) > if (bo->base.resv == &bo->base._resv) > amdgpu_amdkfd_remove_fence_on_pt_pd_bos(abo); > > - if (bo->mem.mem_type != TTM_PL_VRAM || !bo->mem.mm_node || > - !(abo->flags & AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE)) > + if (!(abo->flags & AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE)) > return; > > dma_resv_lock(bo->base.resv, NULL); > > + if (bo->mem.mem_type != TTM_PL_VRAM || !bo->mem.mm_node) { > + dma_resv_unlock(bo->base.resv); > + return; > + } > + > r = amdgpu_fill_buffer(abo, AMDGPU_POISON, bo->base.resv, &fence); > if (!WARN_ON(r)) { > amdgpu_bo_fence(abo, fence, false); > -- > 1.8.3.1 >

4 years, 7 months

Re: [Linaro-mm-sig] [PATCH v2 2/4] drm/msm: Avoid mutex in shrinker_count()

by Rob Clark

On Thu, Apr 1, 2021 at 8:34 AM Doug Anderson <dianders(a)chromium.org> wrote: > > Hi, > > On Wed, Mar 31, 2021 at 6:24 PM Rob Clark <robdclark(a)gmail.com> wrote: > > > > @@ -45,6 +30,9 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) > > list_for_each_entry(msm_obj, &priv->inactive_dontneed, mm_list) { > > if (freed >= sc->nr_to_scan) > > break; > > + /* Use trylock, because we cannot block on a obj that > > + * might be trying to acquire mm_lock > > + */ > > nit: I thought the above multi-line commenting style was only for > "net" subsystem? we do use the "net" style a fair bit already.. (OTOH I tend to not really care what checkpatch says) > > if (!msm_gem_trylock(&msm_obj->base)) > > continue; > > if (is_purgeable(msm_obj)) { > > @@ -56,8 +44,11 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) > > > > mutex_unlock(&priv->mm_lock); > > > > - if (freed > 0) > > + if (freed > 0) { > > trace_msm_gem_purge(freed << PAGE_SHIFT); > > + } else { > > + return SHRINK_STOP; > > + } > > It probably doesn't matter, but I wonder if we should still be > returning SHRINK_STOP if we got any trylock failures. It could > possibly be worth returning 0 in that case? On the surface, you'd think that, but there be mm dragons.. we can hit shrinker from the submit path when the obj is locked already and we are trying to allocate backing pages. We don't want to tell vmscan to keep trying, because we'll keep failing to grab that objects lock > > > @@ -75,6 +66,9 @@ vmap_shrink(struct list_head *mm_list) > > unsigned unmapped = 0; > > > > list_for_each_entry(msm_obj, mm_list, mm_list) { > > + /* Use trylock, because we cannot block on a obj that > > + * might be trying to acquire mm_lock > > + */ > > If you end up changing the commenting style above, should also be here. > > At this point this seems fine to land to me. Though I'm not an expert > on every interaction in this code, I've spent enough time starting at > it that I'm comfortable with: > > Reviewed-by: Douglas Anderson <dianders(a)chromium.org> thanks BR, -R

4 years, 7 months

[PATCH v2 0/4] drm/msm: Shrinker (and related) fixes

by Rob Clark

From: Rob Clark <robdclark(a)chromium.org> I've been spending some time looking into how things behave under high memory pressure. The first patch is a random cleanup I noticed along the way. The second improves the situation significantly when we are getting shrinker called from many threads in parallel. And the last two are $debugfs/gem fixes I needed so I could monitor the state of GEM objects (ie. how many are active/purgable/purged) while triggering high memory pressure. We could probably go a bit further with dropping the mm_lock in the shrinker->scan() loop, but this is already a pretty big improvement. The next step is probably actually to add support to unpin/evict inactive objects. (We are part way there since we have already de- coupled the iova lifetime from the pages lifetime, but there are a few sharp corners to work through.) Rob Clark (4): drm/msm: Remove unused freed llist node drm/msm: Avoid mutex in shrinker_count() drm/msm: Fix debugfs deadlock drm/msm: Improved debugfs gem stats drivers/gpu/drm/msm/msm_debugfs.c | 14 ++--- drivers/gpu/drm/msm/msm_drv.c | 4 ++ drivers/gpu/drm/msm/msm_drv.h | 15 ++++-- drivers/gpu/drm/msm/msm_fb.c | 3 +- drivers/gpu/drm/msm/msm_gem.c | 65 ++++++++++++++++++----- drivers/gpu/drm/msm/msm_gem.h | 72 +++++++++++++++++++++++--- drivers/gpu/drm/msm/msm_gem_shrinker.c | 28 ++++------ 7 files changed, 150 insertions(+), 51 deletions(-) -- 2.30.2

4 years, 8 months

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