6f572a8054
Currently we allocate all 3 levels of radix3 page tables using nvkm_gsp_mem_ctor(), which uses dma_alloc_coherent() for allocating all of the relevant memory. This can end up failing in scenarios where the system has very high memory fragmentation, and we can't find enough contiguous memory to allocate level 2 of the page table. Currently, this can result in runtime PM issues on systems where memory fragmentation is high - as we'll fail to allocate the page table for our suspend/resume buffer: kworker/10:2: page allocation failure: order:7, mode:0xcc0(GFP_KERNEL), nodemask=(null),cpuset=/,mems_allowed=0 CPU: 10 PID: 479809 Comm: kworker/10:2 Not tainted 6.8.6-201.ChopperV6.fc39.x86_64 #1 Hardware name: SLIMBOOK Executive/Executive, BIOS N.1.10GRU06 02/02/2024 Workqueue: pm pm_runtime_work Call Trace: <TASK> dump_stack_lvl+0x64/0x80 warn_alloc+0x165/0x1e0 ? __alloc_pages_direct_compact+0xb3/0x2b0 __alloc_pages_slowpath.constprop.0+0xd7d/0xde0 __alloc_pages+0x32d/0x350 __dma_direct_alloc_pages.isra.0+0x16a/0x2b0 dma_direct_alloc+0x70/0x270 nvkm_gsp_radix3_sg+0x5e/0x130 [nouveau] r535_gsp_fini+0x1d4/0x350 [nouveau] nvkm_subdev_fini+0x67/0x150 [nouveau] nvkm_device_fini+0x95/0x1e0 [nouveau] nvkm_udevice_fini+0x53/0x70 [nouveau] nvkm_object_fini+0xb9/0x240 [nouveau] nvkm_object_fini+0x75/0x240 [nouveau] nouveau_do_suspend+0xf5/0x280 [nouveau] nouveau_pmops_runtime_suspend+0x3e/0xb0 [nouveau] pci_pm_runtime_suspend+0x67/0x1e0 ? __pfx_pci_pm_runtime_suspend+0x10/0x10 __rpm_callback+0x41/0x170 ? __pfx_pci_pm_runtime_suspend+0x10/0x10 rpm_callback+0x5d/0x70 ? __pfx_pci_pm_runtime_suspend+0x10/0x10 rpm_suspend+0x120/0x6a0 pm_runtime_work+0x98/0xb0 process_one_work+0x171/0x340 worker_thread+0x27b/0x3a0 ? __pfx_worker_thread+0x10/0x10 kthread+0xe5/0x120 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x31/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1b/0x30 Luckily, we don't actually need to allocate coherent memory for the page table thanks to being able to pass the GPU a radix3 page table for suspend/resume data. So, let's rewrite nvkm_gsp_radix3_sg() to use the sg allocator for level 2. We continue using coherent allocations for lvl0 and 1, since they only take a single page. V2: * Don't forget to actually jump to the next scatterlist when we reach the end of the scatterlist we're currently on when writing out the page table for level 2 Signed-off-by: Lyude Paul <lyude@redhat.com> Cc: stable@vger.kernel.org Reviewed-by: Ben Skeggs <bskeggs@nvidia.com> Link: https://patchwork.freedesktop.org/patch/msgid/20240429182318.189668-2-lyude@redhat.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.