Re: [RFC PATCH v3 11/11] drm, cgroup: Allow more aggressive memory reclaim

Kenny Ho
2019-06-26T22:52:50Z

Ok. I am not too familiar with shrinker but I will dig into it. Just
so that I am looking into the right things, you are referring to
things like struct shrinker and struct shrink_control?

Regards,
Kenny

On Wed, Jun 26, 2019 at 12:44 PM Daniel Vetter <daniel@ffwll.ch> wrote:
>
> On Wed, Jun 26, 2019 at 11:05:22AM -0400, Kenny Ho wrote:
> > Allow DRM TTM memory manager to register a work_struct, such that, when
> > a drmcgrp is under memory pressure, memory reclaiming can be triggered
> > immediately.
> >
> > Change-Id: I25ac04e2db9c19ff12652b88ebff18b44b2706d8
> > Signed-off-by: Kenny Ho <Kenny.Ho@amd.com>
> > ---
> > drivers/gpu/drm/ttm/ttm_bo.c | 47 +++++++++++++++++++++++++++++++++
> > include/drm/drm_cgroup.h | 14 ++++++++++
> > include/drm/ttm/ttm_bo_driver.h | 2 ++
> > kernel/cgroup/drm.c | 33 +++++++++++++++++++++++
> > 4 files changed, 96 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> > index 79c530f4a198..5fc3bc5bd4c5 100644
> > --- a/drivers/gpu/drm/ttm/ttm_bo.c
> > +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> > @@ -1509,6 +1509,44 @@ int ttm_bo_evict_mm(struct ttm_bo_device *bdev, unsigned mem_type)
> > }
> > EXPORT_SYMBOL(ttm_bo_evict_mm);
> >
> > +static void ttm_bo_reclaim_wq(struct work_struct *work)
> > +{
>
> I think a design a bit more inspired by memcg aware core shrinkers would
> be nice, i.e. explicitly passing:
> - which drm_cgroup needs to be shrunk
> - which ttm_mem_reg (well the fancy new abstracted out stuff for tracking
> special gpu memory resources like tt or vram or whatever)
> - how much it needs to be shrunk
>
> I think with that a lot more the book-keeping could be pushed into the
> drm_cgroup code, and the callback just needs to actually shrink enough as
> requested.
> -Daniel
>
> > + struct ttm_operation_ctx ctx = {
> > + .interruptible = false,
> > + .no_wait_gpu = false,
> > + .flags = TTM_OPT_FLAG_FORCE_ALLOC
> > + };
> > + struct ttm_mem_type_manager *man =
> > + container_of(work, struct ttm_mem_type_manager, reclaim_wq);
> > + struct ttm_bo_device *bdev = man->bdev;
> > + struct dma_fence *fence;
> > + int mem_type;
> > + int ret;
> > +
> > + for (mem_type = 0; mem_type < TTM_NUM_MEM_TYPES; mem_type++)
> > + if (&bdev->man[mem_type] == man)
> > + break;
> > +
> > + BUG_ON(mem_type >= TTM_NUM_MEM_TYPES);
> > +
> > + if (!drmcgrp_mem_pressure_scan(bdev, mem_type))
> > + return;
> > +
> > + ret = ttm_mem_evict_first(bdev, mem_type, NULL, &ctx);
> > + if (ret)
> > + return;
> > +
> > + spin_lock(&man->move_lock);
> > + fence = dma_fence_get(man->move);
> > + spin_unlock(&man->move_lock);
> > +
> > + if (fence) {
> > + ret = dma_fence_wait(fence, false);
> > + dma_fence_put(fence);
> > + }
> > +
> > +}
> > +
> > int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
> > unsigned long p_size)
> > {
> > @@ -1543,6 +1581,13 @@ int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
> > INIT_LIST_HEAD(&man->lru[i]);
> > man->move = NULL;
> >
> > + pr_err("drmcgrp %p type %d\n", bdev->ddev, type);
> > +
> > + if (type <= TTM_PL_VRAM) {
> > + INIT_WORK(&man->reclaim_wq, ttm_bo_reclaim_wq);
> > + drmcgrp_register_device_mm(bdev->ddev, type, &man->reclaim_wq);
> > + }
> > +
> > return 0;
> > }
> > EXPORT_SYMBOL(ttm_bo_init_mm);
> > @@ -1620,6 +1665,8 @@ int ttm_bo_device_release(struct ttm_bo_device *bdev)
> > man = &bdev->man[i];
> > if (man->has_type) {
> > man->use_type = false;
> > + drmcgrp_unregister_device_mm(bdev->ddev, i);
> > + cancel_work_sync(&man->reclaim_wq);
> > if ((i != TTM_PL_SYSTEM) && ttm_bo_clean_mm(bdev, i)) {
> > ret = -EBUSY;
> > pr_err("DRM memory manager type %d is not clean\n",
> > diff --git a/include/drm/drm_cgroup.h b/include/drm/drm_cgroup.h
> > index 360c1e6c809f..134d6e5475f3 100644
> > --- a/include/drm/drm_cgroup.h
> > +++ b/include/drm/drm_cgroup.h
> > @@ -5,6 +5,7 @@
> > #define __DRM_CGROUP_H__
> >
> > #include <linux/cgroup_drm.h>
> > +#include <linux/workqueue.h>
> > #include <drm/ttm/ttm_bo_api.h>
> > #include <drm/ttm/ttm_bo_driver.h>
> >
> > @@ -12,6 +13,9 @@
> >
> > int drmcgrp_register_device(struct drm_device *device);
> > int drmcgrp_unregister_device(struct drm_device *device);
> > +void drmcgrp_register_device_mm(struct drm_device *dev, unsigned type,
> > + struct work_struct *wq);
> > +void drmcgrp_unregister_device_mm(struct drm_device *dev, unsigned type);
> > bool drmcgrp_is_self_or_ancestor(struct drmcgrp *self,
> > struct drmcgrp *relative);
> > void drmcgrp_chg_bo_alloc(struct drmcgrp *drmcgrp, struct drm_device *dev,
> > @@ -40,6 +44,16 @@ static inline int drmcgrp_unregister_device(struct drm_device *device)
> > return 0;
> > }
> >
> > +static inline void drmcgrp_register_device_mm(struct drm_device *dev,
> > + unsigned type, struct work_struct *wq)
> > +{
> > +}
> > +
> > +static inline void drmcgrp_unregister_device_mm(struct drm_device *dev,
> > + unsigned type)
> > +{
> > +}
> > +
> > static inline bool drmcgrp_is_self_or_ancestor(struct drmcgrp *self,
> > struct drmcgrp *relative)
> > {
> > diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
> > index 4cbcb41e5aa9..0956ca7888fc 100644
> > --- a/include/drm/ttm/ttm_bo_driver.h
> > +++ b/include/drm/ttm/ttm_bo_driver.h
> > @@ -205,6 +205,8 @@ struct ttm_mem_type_manager {
> > * Protected by @move_lock.
> > */
> > struct dma_fence *move;
> > +
> > + struct work_struct reclaim_wq;
> > };
> >
> > /**
> > diff --git a/kernel/cgroup/drm.c b/kernel/cgroup/drm.c
> > index 1ce13db36ce9..985a89e849d3 100644
> > --- a/kernel/cgroup/drm.c
> > +++ b/kernel/cgroup/drm.c
> > @@ -31,6 +31,8 @@ struct drmcgrp_device {
> > s64 mem_bw_avg_bytes_per_us_default;
> >
> > s64 mem_highs_default[TTM_PL_PRIV+1];
> > +
> > + struct work_struct *mem_reclaim_wq[TTM_PL_PRIV];
> > };
> >
> > #define DRMCG_CTF_PRIV_SIZE 3
> > @@ -793,6 +795,31 @@ int drmcgrp_unregister_device(struct drm_device *dev)
> > }
> > EXPORT_SYMBOL(drmcgrp_unregister_device);
> >
> > +void drmcgrp_register_device_mm(struct drm_device *dev, unsigned type,
> > + struct work_struct *wq)
> > +{
> > + if (dev == NULL || dev->primary->index > max_minor
> > + || type >= TTM_PL_PRIV)
> > + return;
> > +
> > + mutex_lock(&drmcgrp_mutex);
> > + known_drmcgrp_devs[dev->primary->index]->mem_reclaim_wq[type] = wq;
> > + mutex_unlock(&drmcgrp_mutex);
> > +}
> > +EXPORT_SYMBOL(drmcgrp_register_device_mm);
> > +
> > +void drmcgrp_unregister_device_mm(struct drm_device *dev, unsigned type)
> > +{
> > + if (dev == NULL || dev->primary->index > max_minor
> > + || type >= TTM_PL_PRIV)
> > + return;
> > +
> > + mutex_lock(&drmcgrp_mutex);
> > + known_drmcgrp_devs[dev->primary->index]->mem_reclaim_wq[type] = NULL;
> > + mutex_unlock(&drmcgrp_mutex);
> > +}
> > +EXPORT_SYMBOL(drmcgrp_unregister_device_mm);
> > +
> > bool drmcgrp_is_self_or_ancestor(struct drmcgrp *self, struct drmcgrp *relative)
> > {
> > for (; self != NULL; self = parent_drmcgrp(self))
> > @@ -1004,6 +1031,12 @@ void drmcgrp_mem_track_move(struct ttm_buffer_object *old_bo, bool evict,
> >
> > ddr->mem_bw_stats[DRMCGRP_MEM_BW_ATTR_BYTE_CREDIT]
> > -= move_in_bytes;
> > +
> > + if (known_dev->mem_reclaim_wq[new_mem_type] != NULL &&
> > + ddr->mem_stats[new_mem_type] >
> > + ddr->mem_highs[new_mem_type])
> > + schedule_work(
> > + known_dev->mem_reclaim_wq[new_mem_type]);
> > }
> > mutex_unlock(&known_dev->mutex);
> > }
> > --
> > 2.21.0
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org