From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ... --- drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h | 431 ++++++++++++++++++++++++++++++++ 1 file changed, 431 insertions(+) create mode 100644 drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h (limited to 'drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h') diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h new file mode 100644 index 000000000..97c05d08a --- /dev/null +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h @@ -0,0 +1,431 @@ +/* + * Copyright 2019 Advanced Micro Devices, Inc. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + * + */ + +#ifndef __AMDGPU_MES_H__ +#define __AMDGPU_MES_H__ + +#include "amdgpu_irq.h" +#include "kgd_kfd_interface.h" +#include "amdgpu_gfx.h" +#include + +#define AMDGPU_MES_MAX_COMPUTE_PIPES 8 +#define AMDGPU_MES_MAX_GFX_PIPES 2 +#define AMDGPU_MES_MAX_SDMA_PIPES 2 + +#define AMDGPU_MES_API_VERSION_SHIFT 12 +#define AMDGPU_MES_FEAT_VERSION_SHIFT 24 + +#define AMDGPU_MES_VERSION_MASK 0x00000fff +#define AMDGPU_MES_API_VERSION_MASK 0x00fff000 +#define AMDGPU_MES_FEAT_VERSION_MASK 0xff000000 + +enum amdgpu_mes_priority_level { + AMDGPU_MES_PRIORITY_LEVEL_LOW = 0, + AMDGPU_MES_PRIORITY_LEVEL_NORMAL = 1, + AMDGPU_MES_PRIORITY_LEVEL_MEDIUM = 2, + AMDGPU_MES_PRIORITY_LEVEL_HIGH = 3, + AMDGPU_MES_PRIORITY_LEVEL_REALTIME = 4, + AMDGPU_MES_PRIORITY_NUM_LEVELS +}; + +#define AMDGPU_MES_PROC_CTX_SIZE 0x1000 /* one page area */ +#define AMDGPU_MES_GANG_CTX_SIZE 0x1000 /* one page area */ + +struct amdgpu_mes_funcs; + +enum admgpu_mes_pipe { + AMDGPU_MES_SCHED_PIPE = 0, + AMDGPU_MES_KIQ_PIPE, + AMDGPU_MAX_MES_PIPES = 2, +}; + +struct amdgpu_mes { + struct amdgpu_device *adev; + + struct mutex mutex_hidden; + + struct idr pasid_idr; + struct idr gang_id_idr; + struct idr queue_id_idr; + struct ida doorbell_ida; + + spinlock_t queue_id_lock; + + uint32_t sched_version; + uint32_t kiq_version; + + uint32_t total_max_queue; + uint32_t doorbell_id_offset; + uint32_t max_doorbell_slices; + + uint64_t default_process_quantum; + uint64_t default_gang_quantum; + + struct amdgpu_ring ring; + spinlock_t ring_lock; + + const struct firmware *fw[AMDGPU_MAX_MES_PIPES]; + + /* mes ucode */ + struct amdgpu_bo *ucode_fw_obj[AMDGPU_MAX_MES_PIPES]; + uint64_t ucode_fw_gpu_addr[AMDGPU_MAX_MES_PIPES]; + uint32_t *ucode_fw_ptr[AMDGPU_MAX_MES_PIPES]; + uint64_t uc_start_addr[AMDGPU_MAX_MES_PIPES]; + + /* mes ucode data */ + struct amdgpu_bo *data_fw_obj[AMDGPU_MAX_MES_PIPES]; + uint64_t data_fw_gpu_addr[AMDGPU_MAX_MES_PIPES]; + uint32_t *data_fw_ptr[AMDGPU_MAX_MES_PIPES]; + uint64_t data_start_addr[AMDGPU_MAX_MES_PIPES]; + + /* eop gpu obj */ + struct amdgpu_bo *eop_gpu_obj[AMDGPU_MAX_MES_PIPES]; + uint64_t eop_gpu_addr[AMDGPU_MAX_MES_PIPES]; + + void *mqd_backup[AMDGPU_MAX_MES_PIPES]; + struct amdgpu_irq_src irq[AMDGPU_MAX_MES_PIPES]; + + uint32_t vmid_mask_gfxhub; + uint32_t vmid_mask_mmhub; + uint32_t compute_hqd_mask[AMDGPU_MES_MAX_COMPUTE_PIPES]; + uint32_t gfx_hqd_mask[AMDGPU_MES_MAX_GFX_PIPES]; + uint32_t sdma_hqd_mask[AMDGPU_MES_MAX_SDMA_PIPES]; + uint32_t aggregated_doorbells[AMDGPU_MES_PRIORITY_NUM_LEVELS]; + uint32_t sch_ctx_offs; + uint64_t sch_ctx_gpu_addr; + uint64_t *sch_ctx_ptr; + uint32_t query_status_fence_offs; + uint64_t query_status_fence_gpu_addr; + uint64_t *query_status_fence_ptr; + uint32_t read_val_offs; + uint64_t read_val_gpu_addr; + uint32_t *read_val_ptr; + + uint32_t saved_flags; + + /* initialize kiq pipe */ + int (*kiq_hw_init)(struct amdgpu_device *adev); + int (*kiq_hw_fini)(struct amdgpu_device *adev); + + /* ip specific functions */ + const struct amdgpu_mes_funcs *funcs; +}; + +struct amdgpu_mes_process { + int pasid; + struct amdgpu_vm *vm; + uint64_t pd_gpu_addr; + struct amdgpu_bo *proc_ctx_bo; + uint64_t proc_ctx_gpu_addr; + void *proc_ctx_cpu_ptr; + uint64_t process_quantum; + struct list_head gang_list; + uint32_t doorbell_index; + unsigned long *doorbell_bitmap; + struct mutex doorbell_lock; +}; + +struct amdgpu_mes_gang { + int gang_id; + int priority; + int inprocess_gang_priority; + int global_priority_level; + struct list_head list; + struct amdgpu_mes_process *process; + struct amdgpu_bo *gang_ctx_bo; + uint64_t gang_ctx_gpu_addr; + void *gang_ctx_cpu_ptr; + uint64_t gang_quantum; + struct list_head queue_list; +}; + +struct amdgpu_mes_queue { + struct list_head list; + struct amdgpu_mes_gang *gang; + int queue_id; + uint64_t doorbell_off; + struct amdgpu_bo *mqd_obj; + void *mqd_cpu_ptr; + uint64_t mqd_gpu_addr; + uint64_t wptr_gpu_addr; + int queue_type; + int paging; + struct amdgpu_ring *ring; +}; + +struct amdgpu_mes_queue_properties { + int queue_type; + uint64_t hqd_base_gpu_addr; + uint64_t rptr_gpu_addr; + uint64_t wptr_gpu_addr; + uint64_t wptr_mc_addr; + uint32_t queue_size; + uint64_t eop_gpu_addr; + uint32_t hqd_pipe_priority; + uint32_t hqd_queue_priority; + bool paging; + struct amdgpu_ring *ring; + /* out */ + uint64_t doorbell_off; +}; + +struct amdgpu_mes_gang_properties { + uint32_t priority; + uint32_t gang_quantum; + uint32_t inprocess_gang_priority; + uint32_t priority_level; + int global_priority_level; +}; + +struct mes_add_queue_input { + uint32_t process_id; + uint64_t page_table_base_addr; + uint64_t process_va_start; + uint64_t process_va_end; + uint64_t process_quantum; + uint64_t process_context_addr; + uint64_t gang_quantum; + uint64_t gang_context_addr; + uint32_t inprocess_gang_priority; + uint32_t gang_global_priority_level; + uint32_t doorbell_offset; + uint64_t mqd_addr; + uint64_t wptr_addr; + uint64_t wptr_mc_addr; + uint32_t queue_type; + uint32_t paging; + uint32_t gws_base; + uint32_t gws_size; + uint64_t tba_addr; + uint64_t tma_addr; + uint32_t is_kfd_process; + uint32_t is_aql_queue; + uint32_t queue_size; +}; + +struct mes_remove_queue_input { + uint32_t doorbell_offset; + uint64_t gang_context_addr; +}; + +struct mes_unmap_legacy_queue_input { + enum amdgpu_unmap_queues_action action; + uint32_t queue_type; + uint32_t doorbell_offset; + uint32_t pipe_id; + uint32_t queue_id; + uint64_t trail_fence_addr; + uint64_t trail_fence_data; +}; + +struct mes_suspend_gang_input { + bool suspend_all_gangs; + uint64_t gang_context_addr; + uint64_t suspend_fence_addr; + uint32_t suspend_fence_value; +}; + +struct mes_resume_gang_input { + bool resume_all_gangs; + uint64_t gang_context_addr; +}; + +enum mes_misc_opcode { + MES_MISC_OP_WRITE_REG, + MES_MISC_OP_READ_REG, + MES_MISC_OP_WRM_REG_WAIT, + MES_MISC_OP_WRM_REG_WR_WAIT, +}; + +struct mes_misc_op_input { + enum mes_misc_opcode op; + + union { + struct { + uint32_t reg_offset; + uint64_t buffer_addr; + } read_reg; + + struct { + uint32_t reg_offset; + uint32_t reg_value; + } write_reg; + + struct { + uint32_t ref; + uint32_t mask; + uint32_t reg0; + uint32_t reg1; + } wrm_reg; + }; +}; + +struct amdgpu_mes_funcs { + int (*add_hw_queue)(struct amdgpu_mes *mes, + struct mes_add_queue_input *input); + + int (*remove_hw_queue)(struct amdgpu_mes *mes, + struct mes_remove_queue_input *input); + + int (*unmap_legacy_queue)(struct amdgpu_mes *mes, + struct mes_unmap_legacy_queue_input *input); + + int (*suspend_gang)(struct amdgpu_mes *mes, + struct mes_suspend_gang_input *input); + + int (*resume_gang)(struct amdgpu_mes *mes, + struct mes_resume_gang_input *input); + + int (*misc_op)(struct amdgpu_mes *mes, + struct mes_misc_op_input *input); +}; + +#define amdgpu_mes_kiq_hw_init(adev) (adev)->mes.kiq_hw_init((adev)) +#define amdgpu_mes_kiq_hw_fini(adev) (adev)->mes.kiq_hw_fini((adev)) + +int amdgpu_mes_ctx_get_offs(struct amdgpu_ring *ring, unsigned int id_offs); + +int amdgpu_mes_init(struct amdgpu_device *adev); +void amdgpu_mes_fini(struct amdgpu_device *adev); + +int amdgpu_mes_create_process(struct amdgpu_device *adev, int pasid, + struct amdgpu_vm *vm); +void amdgpu_mes_destroy_process(struct amdgpu_device *adev, int pasid); + +int amdgpu_mes_add_gang(struct amdgpu_device *adev, int pasid, + struct amdgpu_mes_gang_properties *gprops, + int *gang_id); +int amdgpu_mes_remove_gang(struct amdgpu_device *adev, int gang_id); + +int amdgpu_mes_suspend(struct amdgpu_device *adev); +int amdgpu_mes_resume(struct amdgpu_device *adev); + +int amdgpu_mes_add_hw_queue(struct amdgpu_device *adev, int gang_id, + struct amdgpu_mes_queue_properties *qprops, + int *queue_id); +int amdgpu_mes_remove_hw_queue(struct amdgpu_device *adev, int queue_id); + +int amdgpu_mes_unmap_legacy_queue(struct amdgpu_device *adev, + struct amdgpu_ring *ring, + enum amdgpu_unmap_queues_action action, + u64 gpu_addr, u64 seq); + +uint32_t amdgpu_mes_rreg(struct amdgpu_device *adev, uint32_t reg); +int amdgpu_mes_wreg(struct amdgpu_device *adev, + uint32_t reg, uint32_t val); +int amdgpu_mes_reg_wait(struct amdgpu_device *adev, uint32_t reg, + uint32_t val, uint32_t mask); +int amdgpu_mes_reg_write_reg_wait(struct amdgpu_device *adev, + uint32_t reg0, uint32_t reg1, + uint32_t ref, uint32_t mask); + +int amdgpu_mes_add_ring(struct amdgpu_device *adev, int gang_id, + int queue_type, int idx, + struct amdgpu_mes_ctx_data *ctx_data, + struct amdgpu_ring **out); +void amdgpu_mes_remove_ring(struct amdgpu_device *adev, + struct amdgpu_ring *ring); + +uint32_t amdgpu_mes_get_aggregated_doorbell_index(struct amdgpu_device *adev, + enum amdgpu_mes_priority_level prio); + +int amdgpu_mes_ctx_alloc_meta_data(struct amdgpu_device *adev, + struct amdgpu_mes_ctx_data *ctx_data); +void amdgpu_mes_ctx_free_meta_data(struct amdgpu_mes_ctx_data *ctx_data); +int amdgpu_mes_ctx_map_meta_data(struct amdgpu_device *adev, + struct amdgpu_vm *vm, + struct amdgpu_mes_ctx_data *ctx_data); +int amdgpu_mes_ctx_unmap_meta_data(struct amdgpu_device *adev, + struct amdgpu_mes_ctx_data *ctx_data); + +int amdgpu_mes_self_test(struct amdgpu_device *adev); + +int amdgpu_mes_alloc_process_doorbells(struct amdgpu_device *adev, + unsigned int *doorbell_index); +void amdgpu_mes_free_process_doorbells(struct amdgpu_device *adev, + unsigned int doorbell_index); +unsigned int amdgpu_mes_get_doorbell_dw_offset_in_bar( + struct amdgpu_device *adev, + uint32_t doorbell_index, + unsigned int doorbell_id); +int amdgpu_mes_doorbell_process_slice(struct amdgpu_device *adev); + +/* + * MES lock can be taken in MMU notifiers. + * + * A bit more detail about why to set no-FS reclaim with MES lock: + * + * The purpose of the MMU notifier is to stop GPU access to memory so + * that the Linux VM subsystem can move pages around safely. This is + * done by preempting user mode queues for the affected process. When + * MES is used, MES lock needs to be taken to preempt the queues. + * + * The MMU notifier callback entry point in the driver is + * amdgpu_mn_invalidate_range_start_hsa. The relevant call chain from + * there is: + * amdgpu_amdkfd_evict_userptr -> kgd2kfd_quiesce_mm -> + * kfd_process_evict_queues -> pdd->dev->dqm->ops.evict_process_queues + * + * The last part of the chain is a function pointer where we take the + * MES lock. + * + * The problem with taking locks in the MMU notifier is, that MMU + * notifiers can be called in reclaim-FS context. That's where the + * kernel frees up pages to make room for new page allocations under + * memory pressure. While we are running in reclaim-FS context, we must + * not trigger another memory reclaim operation because that would + * recursively reenter the reclaim code and cause a deadlock. The + * memalloc_nofs_save/restore calls guarantee that. + * + * In addition we also need to avoid lock dependencies on other locks taken + * under the MES lock, for example reservation locks. Here is a possible + * scenario of a deadlock: + * Thread A: takes and holds reservation lock | triggers reclaim-FS | + * MMU notifier | blocks trying to take MES lock + * Thread B: takes and holds MES lock | blocks trying to take reservation lock + * + * In this scenario Thread B gets involved in a deadlock even without + * triggering a reclaim-FS operation itself. + * To fix this and break the lock dependency chain you'd need to either: + * 1. protect reservation locks with memalloc_nofs_save/restore, or + * 2. avoid taking reservation locks under the MES lock. + * + * Reservation locks are taken all over the kernel in different subsystems, we + * have no control over them and their lock dependencies.So the only workable + * solution is to avoid taking other locks under the MES lock. + * As a result, make sure no reclaim-FS happens while holding this lock anywhere + * to prevent deadlocks when an MMU notifier runs in reclaim-FS context. + */ +static inline void amdgpu_mes_lock(struct amdgpu_mes *mes) +{ + mutex_lock(&mes->mutex_hidden); + mes->saved_flags = memalloc_noreclaim_save(); +} + +static inline void amdgpu_mes_unlock(struct amdgpu_mes *mes) +{ + memalloc_noreclaim_restore(mes->saved_flags); + mutex_unlock(&mes->mutex_hidden); +} +#endif /* __AMDGPU_MES_H__ */ -- cgit v1.2.3