Rather than relying on the TTM watermark accounting add a shrinker
for xe_bos in TT or system memory.
Leverage the newly added TTM per-page shrinking and shmem backup
support.
Although xe doesn't fully support WONTNEED (purgeable) bos yet,
introduce and add shrinker support for purgeable ttm_tts.
v2:
- Cleanups bugfixes and a KUNIT shrinker test.
- Add writeback support, and activate if kswapd.
v3:
- Move the try_shrink() helper to core TTM.
- Minor cleanups.
v4:
- Add runtime pm for the shrinker. Shrinking may require an active
device for CCS metadata copying.
v5:
- Separately purge ghost- and zombie objects in the shrinker.
- Fix a format specifier - type inconsistency. (Kernel test robot).
v7:
- s/long/s64/ (Christian König)
- s/sofar/progress/ (Matt Brost)
v8:
- Rebase on Xe KUNIT update.
- Add content verifying to the shrinker kunit test.
- Split out TTM changes to a separate patch.
- Get rid of multiple bool arguments for clarity (Matt Brost)
- Avoid an error pointer dereference (Matt Brost)
- Avoid an integer overflow (Matt Auld)
- Address misc review comments by Matt Brost.
v9:
- Fix a compliation error.
- Rebase.
v10:
- Update to new LRU walk interface.
- Rework ghost-, zombie and purged object shrinking.
- Rebase.
Cc: Christian König <christian.koenig@xxxxxxx>
Cc: Somalapuram Amaranath <Amaranath.Somalapuram@xxxxxxx>
Cc: Matthew Brost <matthew.brost@xxxxxxxxx>
Cc: <dri-devel@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/xe/Makefile | 1 +
drivers/gpu/drm/xe/tests/xe_bo.c | 6 +-
drivers/gpu/drm/xe/xe_bo.c | 195 +++++++++++++++++++--
drivers/gpu/drm/xe/xe_bo.h | 36 ++++
drivers/gpu/drm/xe/xe_device.c | 8 +
drivers/gpu/drm/xe/xe_device_types.h | 2 +
drivers/gpu/drm/xe/xe_shrinker.c | 248 +++++++++++++++++++++++++++
drivers/gpu/drm/xe/xe_shrinker.h | 18 ++
8 files changed, 497 insertions(+), 17 deletions(-)
create mode 100644 drivers/gpu/drm/xe/xe_shrinker.c
create mode 100644 drivers/gpu/drm/xe/xe_shrinker.h
diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
index 8f1c5c329f79..16dbabe71e2d 100644
--- a/drivers/gpu/drm/xe/Makefile
+++ b/drivers/gpu/drm/xe/Makefile
@@ -93,6 +93,7 @@ xe-y += xe_bb.o \
xe_ring_ops.o \
xe_sa.o \
xe_sched_job.o \
+ xe_shrinker.o \
xe_step.o \
xe_sync.o \
xe_tile.o \
diff --git a/drivers/gpu/drm/xe/tests/xe_bo.c b/drivers/gpu/drm/xe/tests/xe_bo.c
index 7d3fd720478b..746863cb6e8e 100644
--- a/drivers/gpu/drm/xe/tests/xe_bo.c
+++ b/drivers/gpu/drm/xe/tests/xe_bo.c
@@ -507,8 +507,13 @@ static int shrink_test_run_device(struct xe_device *xe)
* other way around, they may not be subject to swapping...
*/
if (alloced < purgeable) {
+ xe_ttm_tt_account_subtract(&xe_tt->ttm);
xe_tt->purgeable = true;
+ xe_ttm_tt_account_add(&xe_tt->ttm);
bo->ttm.priority = 0;
+ spin_lock(&bo->ttm.bdev->lru_lock);
+ ttm_bo_move_to_lru_tail(&bo->ttm);
+ spin_unlock(&bo->ttm.bdev->lru_lock);
} else {
int ret = shrink_test_fill_random(bo, &prng, link);
@@ -563,7 +568,6 @@ static int shrink_test_run_device(struct xe_device *xe)
if (ret == -EINTR)
intr = true;
} while (ret == -EINTR && !signal_pending(current));
-
if (!ret && !purgeable)
failed = shrink_test_verify(test, bo, count, &prng, link);
diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
index 5f2f1ec46b57..71245f8c3aa3 100644
--- a/drivers/gpu/drm/xe/xe_bo.c
+++ b/drivers/gpu/drm/xe/xe_bo.c
@@ -10,6 +10,7 @@
#include <drm/drm_drv.h>
#include <drm/drm_gem_ttm_helper.h>
#include <drm/drm_managed.h>
+#include <drm/ttm/ttm_backup.h>
#include <drm/ttm/ttm_device.h>
#include <drm/ttm/ttm_placement.h>
#include <drm/ttm/ttm_tt.h>
@@ -25,6 +26,7 @@
#include "xe_pm.h"
#include "xe_preempt_fence.h"
#include "xe_res_cursor.h"
+#include "xe_shrinker.h"
#include "xe_trace_bo.h"
#include "xe_ttm_stolen_mgr.h"
#include "xe_vm.h"
@@ -278,9 +280,11 @@ static void xe_evict_flags(struct ttm_buffer_object *tbo,
}
}
+/* struct xe_ttm_tt - Subclassed ttm_tt for xe */
struct xe_ttm_tt {
struct ttm_tt ttm;
- struct device *dev;
+ /** @xe - The xe device */
+ struct xe_device *xe;
struct sg_table sgt;
struct sg_table *sg;
/** @purgeable: Whether the content of the pages of @ttm is purgeable. */
@@ -293,7 +297,8 @@ static int xe_tt_map_sg(struct ttm_tt *tt)
unsigned long num_pages = tt->num_pages;
int ret;
- XE_WARN_ON(tt->page_flags & TTM_TT_FLAG_EXTERNAL);
+ XE_WARN_ON((tt->page_flags & TTM_TT_FLAG_EXTERNAL) &&
+ !(tt->page_flags & TTM_TT_FLAG_EXTERNAL_MAPPABLE));
if (xe_tt->sg)
return 0;
@@ -301,13 +306,13 @@ static int xe_tt_map_sg(struct ttm_tt *tt)
ret = sg_alloc_table_from_pages_segment(&xe_tt->sgt, tt->pages,
num_pages, 0,
(u64)num_pages << PAGE_SHIFT,
- xe_sg_segment_size(xe_tt->dev),
+ xe_sg_segment_size(xe_tt->xe->drm.dev),
GFP_KERNEL);
if (ret)
return ret;
xe_tt->sg = &xe_tt->sgt;
- ret = dma_map_sgtable(xe_tt->dev, xe_tt->sg, DMA_BIDIRECTIONAL,
+ ret = dma_map_sgtable(xe_tt->xe->drm.dev, xe_tt->sg, DMA_BIDIRECTIONAL,
DMA_ATTR_SKIP_CPU_SYNC);
if (ret) {
sg_free_table(xe_tt->sg);
@@ -323,7 +328,7 @@ static void xe_tt_unmap_sg(struct ttm_tt *tt)
struct xe_ttm_tt *xe_tt = container_of(tt, struct xe_ttm_tt, ttm);
if (xe_tt->sg) {
- dma_unmap_sgtable(xe_tt->dev, xe_tt->sg,
+ dma_unmap_sgtable(xe_tt->xe->drm.dev, xe_tt->sg,
DMA_BIDIRECTIONAL, 0);
sg_free_table(xe_tt->sg);
xe_tt->sg = NULL;
@@ -338,21 +343,47 @@ struct sg_table *xe_bo_sg(struct xe_bo *bo)
return xe_tt->sg;
}
+/*
+ * Account ttm pages against the device shrinker's shrinkable and
+ * purgeable counts.
+ */
+static void xe_ttm_tt_account_add(struct ttm_tt *tt)
+{
+ struct xe_ttm_tt *xe_tt = container_of(tt, struct xe_ttm_tt, ttm);
+
+ if (xe_tt->purgeable)
+ xe_shrinker_mod_pages(xe_tt->xe->mem.shrinker, 0, tt->num_pages);
+ else
+ xe_shrinker_mod_pages(xe_tt->xe->mem.shrinker, tt->num_pages, 0);
+}
+
+static void xe_ttm_tt_account_subtract(struct ttm_tt *tt)
+{
+ struct xe_ttm_tt *xe_tt = container_of(tt, struct xe_ttm_tt, ttm);
+
+ if (xe_tt->purgeable)
+ xe_shrinker_mod_pages(xe_tt->xe->mem.shrinker, 0, -(long)tt->num_pages);
+ else
+ xe_shrinker_mod_pages(xe_tt->xe->mem.shrinker, -(long)tt->num_pages, 0);
+}
+
static struct ttm_tt *xe_ttm_tt_create(struct ttm_buffer_object *ttm_bo,
u32 page_flags)
{
struct xe_bo *bo = ttm_to_xe_bo(ttm_bo);
struct xe_device *xe = xe_bo_device(bo);
- struct xe_ttm_tt *tt;
+ struct xe_ttm_tt *xe_tt;
+ struct ttm_tt *tt;
unsigned long extra_pages;
enum ttm_caching caching = ttm_cached;
int err;
- tt = kzalloc(sizeof(*tt), GFP_KERNEL);
- if (!tt)
+ xe_tt = kzalloc(sizeof(*xe_tt), GFP_KERNEL);
+ if (!xe_tt)
return NULL;
- tt->dev = xe->drm.dev;
+ tt = &xe_tt->ttm;
+ xe_tt->xe = xe;
extra_pages = 0;
if (xe_bo_needs_ccs_pages(bo))
@@ -398,42 +429,60 @@ static struct ttm_tt *xe_ttm_tt_create(struct ttm_buffer_object *ttm_bo,
caching = ttm_uncached;
}
- err = ttm_tt_init(&tt->ttm, &bo->ttm, page_flags, caching, extra_pages);
+ if (ttm_bo->type != ttm_bo_type_sg)
+ page_flags |= TTM_TT_FLAG_EXTERNAL | TTM_TT_FLAG_EXTERNAL_MAPPABLE;
+
+ err = ttm_tt_init(tt, &bo->ttm, page_flags, caching, extra_pages);
if (err) {
- kfree(tt);
+ kfree(xe_tt);
+ return NULL;
+ }
+
+ tt->backup = ttm_backup_shmem_create((loff_t)tt->num_pages << PAGE_SHIFT);
+ if (IS_ERR(tt->backup)) {
+ tt->backup = NULL;
+ ttm_tt_fini(tt);
+ kfree(xe_tt);
return NULL;
}
- return &tt->ttm;
+ return tt;
}
static int xe_ttm_tt_populate(struct ttm_device *ttm_dev, struct ttm_tt *tt,
struct ttm_operation_ctx *ctx)
{
+ struct xe_ttm_tt *xe_tt = container_of(tt, struct xe_ttm_tt, ttm);
int err;
/*
* dma-bufs are not populated with pages, and the dma-
* addresses are set up when moved to XE_PL_TT.
*/
- if (tt->page_flags & TTM_TT_FLAG_EXTERNAL)
+ if ((tt->page_flags & TTM_TT_FLAG_EXTERNAL) &&
+ !(tt->page_flags & TTM_TT_FLAG_EXTERNAL_MAPPABLE))
return 0;
err = ttm_pool_alloc(&ttm_dev->pool, tt, ctx);
if (err)
return err;
- return err;
+ xe_tt->purgeable = false;
+ xe_ttm_tt_account_add(tt);
+
+ return 0;
}
static void xe_ttm_tt_unpopulate(struct ttm_device *ttm_dev, struct ttm_tt *tt)
{
- if (tt->page_flags & TTM_TT_FLAG_EXTERNAL)
+ if ((tt->page_flags & TTM_TT_FLAG_EXTERNAL) &&
+ !(tt->page_flags & TTM_TT_FLAG_EXTERNAL_MAPPABLE))
return;
xe_tt_unmap_sg(tt);
- return ttm_pool_free(&ttm_dev->pool, tt);
+ ttm_pool_free(&ttm_dev->pool, tt);
+ xe_ttm_tt_account_subtract(tt);
}
static void xe_ttm_tt_destroy(struct ttm_device *ttm_dev, struct ttm_tt *tt)
@@ -854,6 +903,112 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict,
return ret;
}
+static long xe_bo_shrink_purge(struct ttm_operation_ctx *ctx,
+ struct ttm_buffer_object *bo,
+ unsigned long *scanned)
+{
+ long lret;
+
+ /* Fake move to system, without copying data. */
+ if (bo->resource->mem_type != XE_PL_SYSTEM) {
+ struct ttm_resource *new_resource;
+
+ lret = ttm_bo_wait_ctx(bo, ctx);
+ if (lret)
+ return lret;
+
+ lret = ttm_bo_mem_space(bo, &sys_placement, &new_resource, ctx);
+ if (lret)
+ return lret;
+
+ xe_tt_unmap_sg(bo->ttm);
+ ttm_bo_move_null(bo, new_resource);
+ }
+
+ *scanned += bo->ttm->num_pages;
+ lret = ttm_bo_try_shrink(ctx, bo, (struct ttm_bo_shrink_flags)
+ {.purge = true,
+ .writeback = false,
+ .allow_move = false});
+
+ if (lret > 0)
+ xe_ttm_tt_account_subtract(bo->ttm);
+
+ return lret;
+}
+
+/**
+ * xe_bo_shrink() - Try to shrink an xe bo.
+ * @ctx: The struct ttm_operation_ctx used for shrinking.
+ * @bo: The TTM buffer object whose pages to shrink.
+ * @flags: Flags governing the shrink behaviour.
+ * @scanned: Pointer to a counter of the number of pages
+ * attempted to shrink.
+ *
+ * Try to shrink- or purge a bo, and if it succeeds, unmap dma.
+ * Note that we need to be able to handle also non xe bos
+ * (ghost bos), but only if the struct ttm_tt is embedded in
+ * a struct xe_ttm_tt. When the function attempts to shrink
+ * the pages of a buffer object, The value pointed to by @scanned
+ * is updated.
+ *
+ * Return: The number of pages shrunken or purged, or negative error
+ * code on failure.
+ */
+long xe_bo_shrink(struct ttm_operation_ctx *ctx, struct ttm_buffer_object *bo,
+ const struct xe_bo_shrink_flags flags,
+ unsigned long *scanned)
+{
+ struct ttm_tt *tt = bo->ttm;
+ struct xe_ttm_tt *xe_tt = container_of(tt, struct xe_ttm_tt, ttm);
+ struct ttm_place place = {.mem_type = bo->resource->mem_type};
+ struct xe_bo *xe_bo = ttm_to_xe_bo(bo);
+ struct xe_device *xe = xe_tt->xe;
+ bool needs_rpm;
+ long lret = 0L;
+
+ if (!tt || !ttm_tt_is_populated(tt) ||
+ !(tt->page_flags & TTM_TT_FLAG_EXTERNAL_MAPPABLE) ||
+ (flags.purge && !xe_tt->purgeable))
+ return 0L;
+
+ if (!ttm_bo_eviction_valuable(bo, &place))
+ return 0L;
+
+ if (!xe_bo_is_xe_bo(bo) || !xe_bo_get_unless_zero(xe_bo))
+ return xe_bo_shrink_purge(ctx, bo, scanned);
+
+ if (xe_tt->purgeable) {
+ if (bo->resource->mem_type != XE_PL_SYSTEM)
+ lret = xe_bo_move_notify(xe_bo, ctx);
+ if (!lret)
+ lret = xe_bo_shrink_purge(ctx, bo, scanned);
+ goto out_unref;
+ }
+
+ /* System CCS needs gpu copy when moving PL_TT -> PL_SYSTEM */
+ needs_rpm = (!IS_DGFX(xe) && bo->resource->mem_type != XE_PL_SYSTEM &&
+ xe_bo_needs_ccs_pages(xe_bo));
+ if (needs_rpm && !xe_pm_runtime_get_if_active(xe))
+ goto out_unref;
+
+ *scanned += tt->num_pages;
+ lret = ttm_bo_try_shrink(ctx, bo, (struct ttm_bo_shrink_flags)
+ {.purge = false,
+ .writeback = flags.writeback,
+ .allow_move = true});
+ if (needs_rpm)
+ xe_pm_runtime_put(xe);
+
+ if (lret > 0)
+ xe_ttm_tt_account_subtract(tt);
+
+out_unref:
+ xe_bo_put(xe_bo);
+
+ return lret;
+}
+
/**
* xe_bo_evict_pinned() - Evict a pinned VRAM object to system memory
* @bo: The buffer object to move.
@@ -1737,6 +1892,8 @@ int xe_bo_pin_external(struct xe_bo *bo)
}
ttm_bo_pin(&bo->ttm);
+ if (bo->ttm.ttm && ttm_tt_is_populated(bo->ttm.ttm))
+ xe_ttm_tt_account_subtract(bo->ttm.ttm);
/*
* FIXME: If we always use the reserve / unreserve functions for locking
@@ -1795,6 +1952,8 @@ int xe_bo_pin(struct xe_bo *bo)
}
ttm_bo_pin(&bo->ttm);
+ if (bo->ttm.ttm && ttm_tt_is_populated(bo->ttm.ttm))
+ xe_ttm_tt_account_subtract(bo->ttm.ttm);
/*
* FIXME: If we always use the reserve / unreserve functions for locking
@@ -1829,6 +1988,8 @@ void xe_bo_unpin_external(struct xe_bo *bo)
spin_unlock(&xe->pinned.lock);
ttm_bo_unpin(&bo->ttm);
+ if (bo->ttm.ttm && ttm_tt_is_populated(bo->ttm.ttm))
+ xe_ttm_tt_account_add(bo->ttm.ttm);
/*
* FIXME: If we always use the reserve / unreserve functions for locking
@@ -1857,6 +2018,8 @@ void xe_bo_unpin(struct xe_bo *bo)
}
ttm_bo_unpin(&bo->ttm);
+ if (bo->ttm.ttm && ttm_tt_is_populated(bo->ttm.ttm))
+ xe_ttm_tt_account_add(bo->ttm.ttm);
}
/**
diff --git a/drivers/gpu/drm/xe/xe_bo.h b/drivers/gpu/drm/xe/xe_bo.h
index 6e4be52306df..f2ae1c8ee2eb 100644
--- a/drivers/gpu/drm/xe/xe_bo.h
+++ b/drivers/gpu/drm/xe/xe_bo.h
@@ -128,6 +128,28 @@ static inline struct xe_bo *xe_bo_get(struct xe_bo *bo)
void xe_bo_put(struct xe_bo *bo);
+/*
+ * xe_bo_get_unless_zero() - Conditionally obtain a GEM object refcount on an
+ * xe bo
+ * @bo: The bo for which we want to obtain a refcount.
+ *
+ * There is a short window between where the bo's GEM object refcount reaches
+ * zero and where we put the final ttm_bo reference. Code in the eviction- and
+ * shrinking path should therefore attempt to grab a gem object reference before
+ * trying to use members outside of the base class ttm object. This function is
+ * intended for that purpose. On successful return, this function must be paired
+ * with an xe_bo_put().
+ *
+ * Return: @bo on success, NULL on failure.
+ */
+static inline __must_check struct xe_bo *xe_bo_get_unless_zero(struct xe_bo *bo)
+{
+ if (!bo || !kref_get_unless_zero(&bo->ttm.base.refcount))
+ return NULL;
+
+ return bo;
+}
+
static inline void __xe_bo_unset_bulk_move(struct xe_bo *bo)
{
if (bo)
@@ -314,6 +336,20 @@ static inline unsigned int xe_sg_segment_size(struct device *dev)
#define i915_gem_object_flush_if_display(obj) ((void)(obj))
+/**
+ * struct xe_bo_shrink_flags - flags governing the shrink behaviour.
+ * @purge: Only purging allowed. Don't shrink if bo not purgeable.
+ * @writeback: Attempt to immediately move content to swap.
+ */
+struct xe_bo_shrink_flags {
+ u32 purge : 1;
+ u32 writeback : 1;
+};
+
+long xe_bo_shrink(struct ttm_operation_ctx *ctx, struct ttm_buffer_object *bo,
+ const struct xe_bo_shrink_flags flags,
+ unsigned long *scanned);
+
#if IS_ENABLED(CONFIG_DRM_XE_KUNIT_TEST)
/**
* xe_bo_is_mem_type - Whether the bo currently resides in the given
diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 4d3c794f134c..b2d7b8e11355 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -48,6 +48,7 @@
#include "xe_pcode.h"
#include "xe_pm.h"
#include "xe_query.h"
+#include "xe_shrinker.h"
#include "xe_sriov.h"
#include "xe_tile.h"
#include "xe_ttm_stolen_mgr.h"
@@ -297,6 +298,9 @@ static void xe_device_destroy(struct drm_device *dev, void *dummy)
if (xe->unordered_wq)
destroy_workqueue(xe->unordered_wq);
+ if (!IS_ERR_OR_NULL(xe->mem.shrinker))
+ xe_shrinker_destroy(xe->mem.shrinker);
+
ttm_device_fini(&xe->ttm);
}
@@ -326,6 +330,10 @@ struct xe_device *xe_device_create(struct pci_dev *pdev,
if (err)
goto err;
+ xe->mem.shrinker = xe_shrinker_create(xe);
+ if (IS_ERR(xe->mem.shrinker))
+ return ERR_CAST(xe->mem.shrinker);
+
xe->info.devid = pdev->device;
xe->info.revid = pdev->revision;
xe->info.force_execlist = xe_modparam.force_execlist;
diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index c92df0a2423f..610f262fcd7d 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -365,6 +365,8 @@ struct xe_device {
struct xe_mem_region vram;
/** @mem.sys_mgr: system TTM manager */
struct ttm_resource_manager sys_mgr;
+ /** @mem.sys_mgr: system memory shrinker. */
+ struct xe_shrinker *shrinker;
} mem;
/** @sriov: device level virtualization data */
diff --git a/drivers/gpu/drm/xe/xe_shrinker.c b/drivers/gpu/drm/xe/xe_shrinker.c
new file mode 100644
index 000000000000..32f83316146c
--- /dev/null
+++ b/drivers/gpu/drm/xe/xe_shrinker.c
@@ -0,0 +1,248 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2024 Intel Corporation
+ */
+
+#include <linux/shrinker.h>
+#include <linux/swap.h>
+
+#include <drm/ttm/ttm_bo.h>
+#include <drm/ttm/ttm_tt.h>
+
+#include "xe_bo.h"
+#include "xe_pm.h"
+#include "xe_shrinker.h"
+
+/**
+ * struct xe_shrinker - per-device shrinker
+ * @xe: Back pointer to the device.
+ * @lock: Lock protecting accounting.
+ * @shrinkable_pages: Number of pages that are currently shrinkable.
+ * @purgeable_pages: Number of pages that are currently purgeable.
+ * @shrink: Pointer to the mm shrinker.
+ * @pm_worker: Worker to wake up the device if required.
+ */
+struct xe_shrinker {
+ struct xe_device *xe;
+ rwlock_t lock;
+ long shrinkable_pages;
+ long purgeable_pages;
+ struct shrinker *shrink;
+ struct work_struct pm_worker;
+};
+
+static struct xe_shrinker *to_xe_shrinker(struct shrinker *shrink)
+{
+ return shrink->private_data;
+}
+
+/**
+ * xe_shrinker_mod_pages() - Modify shrinker page accounting
+ * @shrinker: Pointer to the struct xe_shrinker.
+ * @shrinkable: Shrinkable pages delta. May be negative.
+ * @purgeable: Purgeable page delta. May be negative.
+ *
+ * Modifies the shrinkable and purgeable pages accounting.
+ */
+void
+xe_shrinker_mod_pages(struct xe_shrinker *shrinker, long shrinkable, long purgeable)
+{
+ write_lock(&shrinker->lock);
+ shrinker->shrinkable_pages += shrinkable;
+ shrinker->purgeable_pages += purgeable;
+ write_unlock(&shrinker->lock);
+}
+
+static s64 xe_shrinker_walk(struct xe_device *xe,
+ struct ttm_operation_ctx *ctx,
+ const struct xe_bo_shrink_flags flags,
+ unsigned long to_scan, unsigned long *scanned)
+{
+ unsigned int mem_type;
+ s64 freed = 0, lret;
+
+ for (mem_type = XE_PL_SYSTEM; mem_type <= XE_PL_TT; ++mem_type) {
+ struct ttm_resource_manager *man = ttm_manager_type(&xe->ttm, mem_type);
+ struct ttm_bo_lru_cursor curs;
+ struct ttm_buffer_object *ttm_bo;
+
+ if (!man || !man->use_tt)
+ continue;
+
+ ttm_bo_lru_for_each_reserved_guarded(&curs, man, ctx, ttm_bo) {
+ lret = xe_bo_shrink(ctx, ttm_bo, flags, scanned);
+ if (lret < 0)
+ return lret;
+
+ freed += lret;
+ if (*scanned >= to_scan)
+ break;
+ }
+ }
+
+ return freed;
+}
+
+static unsigned long
+xe_shrinker_count(struct shrinker *shrink, struct shrink_control *sc)
+{
+ struct xe_shrinker *shrinker = to_xe_shrinker(shrink);
+ unsigned long num_pages;
+
+ num_pages = get_nr_swap_pages();
+ read_lock(&shrinker->lock);
+ num_pages = min_t(unsigned long, num_pages, shrinker->shrinkable_pages);
+ num_pages += shrinker->purgeable_pages;
+ read_unlock(&shrinker->lock);
+
+ return num_pages ? num_pages : SHRINK_EMPTY;
+}
+
+/*
+ * Check if we need runtime pm, and if so try to grab a reference if
+ * already active. If grabbing a reference fails, queue a worker that
+ * does it for us outside of reclaim, but don't wait for it to complete.
+ * If bo shrinking needs an rpm reference and we don't have it (yet),
+ * that bo will be skipped anyway.
+ */
+static bool xe_shrinker_runtime_pm_get(struct xe_shrinker *shrinker, bool force,
+ unsigned long nr_to_scan)
+{
+ struct xe_device *xe = shrinker->xe;
+
+ if (IS_DGFX(xe) || !xe_device_has_flat_ccs(xe) ||
+ !get_nr_swap_pages())
+ return false;
+
+ if (!force) {
+ read_lock(&shrinker->lock);
+ force = (nr_to_scan > shrinker->purgeable_pages);
+ read_unlock(&shrinker->lock);
+ if (!force)
+ return false;
+ }
+
+ if (!xe_pm_runtime_get_if_active(xe)) {
+ if (xe_rpm_reclaim_safe(xe) && current_is_kswapd()) {
+ xe_pm_runtime_get(xe);
+ return true;
+ }
+ queue_work(xe->unordered_wq, &shrinker->pm_worker);
+ return false;
+ }
+
+ return true;
+}
+
+static void xe_shrinker_runtime_pm_put(struct xe_shrinker *shrinker, bool runtime_pm)
+{
+ if (runtime_pm)
+ xe_pm_runtime_put(shrinker->xe);
+}
+
+static unsigned long xe_shrinker_scan(struct shrinker *shrink, struct shrink_control *sc)
+{
+ struct xe_shrinker *shrinker = to_xe_shrinker(shrink);
+ bool is_kswapd = current_is_kswapd();
+ struct ttm_operation_ctx ctx = {
+ .interruptible = false,
+ .no_wait_gpu = !is_kswapd,
+ };
+ unsigned long nr_to_scan, nr_scanned = 0, freed = 0;
+ struct xe_bo_shrink_flags shrink_flags = {
+ .purge = true,
+ .writeback = is_kswapd,
+ };
+ bool runtime_pm;
+ bool purgeable;
+ s64 lret;
+
+ nr_to_scan = sc->nr_to_scan;
+
+ read_lock(&shrinker->lock);
+ purgeable = !!shrinker->purgeable_pages;
+ read_unlock(&shrinker->lock);
+
+ /* Might need runtime PM. Try to wake early if it looks like it. */
+ runtime_pm = xe_shrinker_runtime_pm_get(shrinker, false, nr_to_scan);
+
+ if (purgeable && nr_scanned < nr_to_scan) {
+ lret = xe_shrinker_walk(shrinker->xe, &ctx, shrink_flags,
+ nr_to_scan, &nr_scanned);
+ if (lret >= 0)
+ freed += lret;
+ }
+
+ sc->nr_scanned = nr_scanned;
+ if (nr_scanned >= nr_to_scan)
+ goto out;
+
+ /* If we didn't wake before, try to do it now if needed. */
+ if (!runtime_pm)
+ runtime_pm = xe_shrinker_runtime_pm_get(shrinker, true, 0);
+
+ shrink_flags.purge = false;
+ lret = xe_shrinker_walk(shrinker->xe, &ctx, shrink_flags,
+ nr_to_scan, &nr_scanned);
+ if (lret >= 0)
+ freed += lret;
+
+ sc->nr_scanned = nr_scanned;
+out:
+ xe_shrinker_runtime_pm_put(shrinker, runtime_pm);
+ return nr_scanned ? freed : SHRINK_STOP;
+}
+
+/* Wake up the device for shrinking. */
+static void xe_shrinker_pm(struct work_struct *work)
+{
+ struct xe_shrinker *shrinker =
+ container_of(work, typeof(*shrinker), pm_worker);
+
+ xe_pm_runtime_get(shrinker->xe);
+ xe_pm_runtime_put(shrinker->xe);
+}
+
+/**
+ * xe_shrinker_create() - Create an xe per-device shrinker
+ * @xe: Pointer to the xe device.
+ *
+ * Returns: A pointer to the created shrinker on success,
+ * Negative error code on failure.
+ */
+struct xe_shrinker *xe_shrinker_create(struct xe_device *xe)
+{
+ struct xe_shrinker *shrinker = kzalloc(sizeof(*shrinker), GFP_KERNEL);
+
+ if (!shrinker)
+ return ERR_PTR(-ENOMEM);
+
+ shrinker->shrink = shrinker_alloc(0, "xe system shrinker");
+ if (!shrinker->shrink) {
+ kfree(shrinker);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ INIT_WORK(&shrinker->pm_worker, xe_shrinker_pm);
+ shrinker->xe = xe;
+ rwlock_init(&shrinker->lock);
+ shrinker->shrink->count_objects = xe_shrinker_count;
+ shrinker->shrink->scan_objects = xe_shrinker_scan;
+ shrinker->shrink->private_data = shrinker;
+ shrinker_register(shrinker->shrink);
+
+ return shrinker;
+}
+
+/**
+ * xe_shrinker_destroy() - Destroy an xe per-device shrinker
+ * @shrinker: Pointer to the shrinker to destroy.
+ */
+void xe_shrinker_destroy(struct xe_shrinker *shrinker)
+{
+ xe_assert(shrinker->xe, !shrinker->shrinkable_pages);
+ xe_assert(shrinker->xe, !shrinker->purgeable_pages);
+ shrinker_free(shrinker->shrink);
+ flush_work(&shrinker->pm_worker);
+ kfree(shrinker);
+}
diff --git a/drivers/gpu/drm/xe/xe_shrinker.h b/drivers/gpu/drm/xe/xe_shrinker.h
new file mode 100644
index 000000000000..28a038f4fcbf
--- /dev/null
+++ b/drivers/gpu/drm/xe/xe_shrinker.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2024 Intel Corporation
+ */
+
+#ifndef _XE_SHRINKER_H_
+#define _XE_SHRINKER_H_
+
+struct xe_shrinker;
+struct xe_device;
+
+void xe_shrinker_mod_pages(struct xe_shrinker *shrinker, long shrinkable, long purgeable);
+
+struct xe_shrinker *xe_shrinker_create(struct xe_device *xe);
+
+void xe_shrinker_destroy(struct xe_shrinker *shrinker);
+
+#endif
--
2.46.0
