[Intel-gfx] [PATCH] drm/i915: Use dma_resv_iter for waiting in i915_gem_object_wait_reservation.
Maarten Lankhorst
maarten.lankhorst at linux.intel.com
Wed Oct 13 12:32:03 UTC 2021
No memory should be allocated when calling i915_gem_object_wait,
because it may be called to idle a BO when evicting memory.
Fix this by using dma_resv_iter helpers to call
i915_gem_object_wait_fence() on each fence, which cleans up the code a lot.
Also remove dma_resv_prune, it's questionably.
This will result in the following lockdep splat.
<4> [83.538517] ======================================================
<4> [83.538520] WARNING: possible circular locking dependency detected
<4> [83.538522] 5.15.0-rc5-CI-Trybot_8062+ #1 Not tainted
<4> [83.538525] ------------------------------------------------------
<4> [83.538527] gem_render_line/5242 is trying to acquire lock:
<4> [83.538530] ffffffff8275b1e0 (fs_reclaim){+.+.}-{0:0}, at: __kmalloc_track_caller+0x56/0x270
<4> [83.538538]
but task is already holding lock:
<4> [83.538540] ffff88813471d1e0 (&vm->mutex/1){+.+.}-{3:3}, at: i915_vma_pin_ww+0x1c7/0x970 [i915]
<4> [83.538638]
which lock already depends on the new lock.
<4> [83.538642]
the existing dependency chain (in reverse order) is:
<4> [83.538645]
-> #1 (&vm->mutex/1){+.+.}-{3:3}:
<4> [83.538649] lock_acquire+0xd3/0x310
<4> [83.538654] i915_gem_shrinker_taints_mutex+0x2d/0x50 [i915]
<4> [83.538730] i915_address_space_init+0xf5/0x1b0 [i915]
<4> [83.538794] ppgtt_init+0x55/0x70 [i915]
<4> [83.538856] gen8_ppgtt_create+0x44/0x5d0 [i915]
<4> [83.538912] i915_ppgtt_create+0x28/0xf0 [i915]
<4> [83.538971] intel_gt_init+0x130/0x3b0 [i915]
<4> [83.539029] i915_gem_init+0x14b/0x220 [i915]
<4> [83.539100] i915_driver_probe+0x97e/0xdd0 [i915]
<4> [83.539149] i915_pci_probe+0x43/0x1d0 [i915]
<4> [83.539197] pci_device_probe+0x9b/0x110
<4> [83.539201] really_probe+0x1b0/0x3b0
<4> [83.539205] __driver_probe_device+0xf6/0x170
<4> [83.539208] driver_probe_device+0x1a/0x90
<4> [83.539210] __driver_attach+0x93/0x160
<4> [83.539213] bus_for_each_dev+0x72/0xc0
<4> [83.539216] bus_add_driver+0x14b/0x1f0
<4> [83.539220] driver_register+0x66/0xb0
<4> [83.539222] hdmi_get_spk_alloc+0x1f/0x50 [snd_hda_codec_hdmi]
<4> [83.539227] do_one_initcall+0x53/0x2e0
<4> [83.539230] do_init_module+0x55/0x200
<4> [83.539234] load_module+0x2700/0x2980
<4> [83.539237] __do_sys_finit_module+0xaa/0x110
<4> [83.539241] do_syscall_64+0x37/0xb0
<4> [83.539244] entry_SYSCALL_64_after_hwframe+0x44/0xae
<4> [83.539247]
-> #0 (fs_reclaim){+.+.}-{0:0}:
<4> [83.539251] validate_chain+0xb37/0x1e70
<4> [83.539254] __lock_acquire+0x5a1/0xb70
<4> [83.539258] lock_acquire+0xd3/0x310
<4> [83.539260] fs_reclaim_acquire+0x9d/0xd0
<4> [83.539264] __kmalloc_track_caller+0x56/0x270
<4> [83.539267] krealloc+0x48/0xa0
<4> [83.539270] dma_resv_get_fences+0x1c3/0x280
<4> [83.539274] i915_gem_object_wait+0x1ff/0x410 [i915]
<4> [83.539342] i915_gem_evict_for_node+0x16b/0x440 [i915]
<4> [83.539412] i915_gem_gtt_reserve+0xff/0x130 [i915]
<4> [83.539482] i915_vma_pin_ww+0x765/0x970 [i915]
<4> [83.539556] eb_validate_vmas+0x6fe/0x8e0 [i915]
<4> [83.539626] i915_gem_do_execbuffer+0x9a6/0x20a0 [i915]
<4> [83.539693] i915_gem_execbuffer2_ioctl+0x11f/0x2c0 [i915]
<4> [83.539759] drm_ioctl_kernel+0xac/0x140
<4> [83.539763] drm_ioctl+0x201/0x3d0
<4> [83.539766] __x64_sys_ioctl+0x6a/0xa0
<4> [83.539769] do_syscall_64+0x37/0xb0
<4> [83.539772] entry_SYSCALL_64_after_hwframe+0x44/0xae
<4> [83.539775]
other info that might help us debug this:
<4> [83.539778] Possible unsafe locking scenario:
<4> [83.539781] CPU0 CPU1
<4> [83.539783] ---- ----
<4> [83.539785] lock(&vm->mutex/1);
<4> [83.539788] lock(fs_reclaim);
<4> [83.539791] lock(&vm->mutex/1);
<4> [83.539794] lock(fs_reclaim);
<4> [83.539796]
*** DEADLOCK ***
<4> [83.539799] 3 locks held by gem_render_line/5242:
<4> [83.539802] #0: ffffc90000d4bbf0 (reservation_ww_class_acquire){+.+.}-{0:0}, at: i915_gem_do_execbuffer+0x8e5/0x20a0 [i915]
<4> [83.539870] #1: ffff88811e48bae8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: eb_validate_vmas+0x81/0x8e0 [i915]
<4> [83.539936] #2: ffff88813471d1e0 (&vm->mutex/1){+.+.}-{3:3}, at: i915_vma_pin_ww+0x1c7/0x970 [i915]
<4> [83.540011]
stack backtrace:
<4> [83.540014] CPU: 2 PID: 5242 Comm: gem_render_line Not tainted 5.15.0-rc5-CI-Trybot_8062+ #1
<4> [83.540019] Hardware name: Intel(R) Client Systems NUC11TNHi3/NUC11TNBi3, BIOS TNTGL357.0038.2020.1124.1648 11/24/2020
<4> [83.540023] Call Trace:
<4> [83.540026] dump_stack_lvl+0x56/0x7b
<4> [83.540030] check_noncircular+0x12e/0x150
<4> [83.540034] ? _raw_spin_unlock_irqrestore+0x50/0x60
<4> [83.540038] validate_chain+0xb37/0x1e70
<4> [83.540042] __lock_acquire+0x5a1/0xb70
<4> [83.540046] lock_acquire+0xd3/0x310
<4> [83.540049] ? __kmalloc_track_caller+0x56/0x270
<4> [83.540052] ? find_held_lock+0x2d/0x90
<4> [83.540055] ? dma_resv_get_fences+0x1c3/0x280
<4> [83.540058] fs_reclaim_acquire+0x9d/0xd0
<4> [83.540061] ? __kmalloc_track_caller+0x56/0x270
<4> [83.540064] __kmalloc_track_caller+0x56/0x270
<4> [83.540067] krealloc+0x48/0xa0
<4> [83.540070] dma_resv_get_fences+0x1c3/0x280
<4> [83.540074] i915_gem_object_wait+0x1ff/0x410 [i915]
<4> [83.540143] i915_gem_evict_for_node+0x16b/0x440 [i915]
<4> [83.540212] i915_gem_gtt_reserve+0xff/0x130 [i915]
<4> [83.540281] i915_vma_pin_ww+0x765/0x970 [i915]
<4> [83.540354] eb_validate_vmas+0x6fe/0x8e0 [i915]
<4> [83.540420] i915_gem_do_execbuffer+0x9a6/0x20a0 [i915]
<4> [83.540485] ? lockdep_hardirqs_on+0xbf/0x130
<4> [83.540490] ? __lock_acquire+0x5c0/0xb70
<4> [83.540495] i915_gem_execbuffer2_ioctl+0x11f/0x2c0 [i915]
<4> [83.540559] ? i915_gem_do_execbuffer+0x20a0/0x20a0 [i915]
<4> [83.540622] drm_ioctl_kernel+0xac/0x140
<4> [83.540625] drm_ioctl+0x201/0x3d0
<4> [83.540628] ? i915_gem_do_execbuffer+0x20a0/0x20a0 [i915]
<4> [83.540691] __x64_sys_ioctl+0x6a/0xa0
<4> [83.540694] do_syscall_64+0x37/0xb0
<4> [83.540697] entry_SYSCALL_64_after_hwframe+0x44/0xae
<4> [83.540700] RIP: 0033:0x7fc314edc50b
Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
drivers/gpu/drm/i915/Makefile | 1 -
drivers/gpu/drm/i915/dma_resv_utils.c | 17 ------
drivers/gpu/drm/i915/dma_resv_utils.h | 13 -----
drivers/gpu/drm/i915/gem/i915_gem_shrinker.c | 1 -
drivers/gpu/drm/i915/gem/i915_gem_wait.c | 56 +++-----------------
5 files changed, 8 insertions(+), 80 deletions(-)
delete mode 100644 drivers/gpu/drm/i915/dma_resv_utils.c
delete mode 100644 drivers/gpu/drm/i915/dma_resv_utils.h
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 21b05ed0e4e8..88bb326d9031 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -58,7 +58,6 @@ i915-y += i915_drv.o \
# core library code
i915-y += \
- dma_resv_utils.o \
i915_memcpy.o \
i915_mm.o \
i915_sw_fence.o \
diff --git a/drivers/gpu/drm/i915/dma_resv_utils.c b/drivers/gpu/drm/i915/dma_resv_utils.c
deleted file mode 100644
index 7df91b7e4ca8..000000000000
--- a/drivers/gpu/drm/i915/dma_resv_utils.c
+++ /dev/null
@@ -1,17 +0,0 @@
-// SPDX-License-Identifier: MIT
-/*
- * Copyright © 2020 Intel Corporation
- */
-
-#include <linux/dma-resv.h>
-
-#include "dma_resv_utils.h"
-
-void dma_resv_prune(struct dma_resv *resv)
-{
- if (dma_resv_trylock(resv)) {
- if (dma_resv_test_signaled(resv, true))
- dma_resv_add_excl_fence(resv, NULL);
- dma_resv_unlock(resv);
- }
-}
diff --git a/drivers/gpu/drm/i915/dma_resv_utils.h b/drivers/gpu/drm/i915/dma_resv_utils.h
deleted file mode 100644
index b9d8fb5f8367..000000000000
--- a/drivers/gpu/drm/i915/dma_resv_utils.h
+++ /dev/null
@@ -1,13 +0,0 @@
-/* SPDX-License-Identifier: MIT */
-/*
- * Copyright © 2020 Intel Corporation
- */
-
-#ifndef DMA_RESV_UTILS_H
-#define DMA_RESV_UTILS_H
-
-struct dma_resv;
-
-void dma_resv_prune(struct dma_resv *resv);
-
-#endif /* DMA_RESV_UTILS_H */
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
index c80e6c1d2bcb..5375f3f9f016 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
@@ -15,7 +15,6 @@
#include "gt/intel_gt_requests.h"
-#include "dma_resv_utils.h"
#include "i915_trace.h"
static bool swap_available(void)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_wait.c b/drivers/gpu/drm/i915/gem/i915_gem_wait.c
index f909aaa09d9c..e59304a76b2c 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_wait.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_wait.c
@@ -10,7 +10,6 @@
#include "gt/intel_engine.h"
-#include "dma_resv_utils.h"
#include "i915_gem_ioctls.h"
#include "i915_gem_object.h"
@@ -37,56 +36,17 @@ i915_gem_object_wait_reservation(struct dma_resv *resv,
unsigned int flags,
long timeout)
{
- struct dma_fence *excl;
- bool prune_fences = false;
-
- if (flags & I915_WAIT_ALL) {
- struct dma_fence **shared;
- unsigned int count, i;
- int ret;
+ struct dma_resv_iter cursor;
+ struct dma_fence *fence;
- ret = dma_resv_get_fences(resv, &excl, &count, &shared);
- if (ret)
- return ret;
-
- for (i = 0; i < count; i++) {
- timeout = i915_gem_object_wait_fence(shared[i],
- flags, timeout);
- if (timeout < 0)
- break;
+ dma_resv_iter_begin(&cursor, resv, flags & I915_WAIT_ALL);
+ dma_resv_for_each_fence_unlocked(&cursor, fence) {
- dma_fence_put(shared[i]);
- }
-
- for (; i < count; i++)
- dma_fence_put(shared[i]);
- kfree(shared);
-
- /*
- * If both shared fences and an exclusive fence exist,
- * then by construction the shared fences must be later
- * than the exclusive fence. If we successfully wait for
- * all the shared fences, we know that the exclusive fence
- * must all be signaled. If all the shared fences are
- * signaled, we can prune the array and recover the
- * floating references on the fences/requests.
- */
- prune_fences = count && timeout >= 0;
- } else {
- excl = dma_resv_get_excl_unlocked(resv);
+ timeout = i915_gem_object_wait_fence(fence, flags, timeout);
+ if (timeout <= 0)
+ break;
}
-
- if (excl && timeout >= 0)
- timeout = i915_gem_object_wait_fence(excl, flags, timeout);
-
- dma_fence_put(excl);
-
- /*
- * Opportunistically prune the fences iff we know they have *all* been
- * signaled.
- */
- if (prune_fences)
- dma_resv_prune(resv);
+ dma_resv_iter_end(&cursor);
return timeout;
}
--
2.33.0
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