search for: mmu_interval_read_retry

...seq - Save the invalidation sequence + * @mni - The mni passed to invalidate + * @cur_seq - The cur_seq passed to the invalidate() callback + * + * This must be called unconditionally from the invalidate callback of a + * struct mmu_interval_notifier_ops under the same lock that is used to call + * mmu_interval_read_retry(). It updates the sequence number for later use by + * mmu_interval_read_retry(). The provided cur_seq will always be odd. + * + * If the caller does not call mmu_interval_read_begin() or + * mmu_interval_read_retry() then this call is not required. + */ +static inline void mmu_interval_set_seq(str...

...truct amdgpu_bo *bo, struct page **pages) > down_read(&mm->mmap_sem); > r = hmm_range_fault(range); > up_read(&mm->mmap_sem); > - if (unlikely(r <= 0)) { > + if (unlikely(r)) { > /* > * FIXME: This timeout should encompass the retry from > * mmu_interval_read_retry() as well. > */ > - if ((r == 0 || r == -EBUSY) && !time_after(jiffies, timeout)) > + if ((r == -EBUSY) && !time_after(jiffies, timeout)) Please also kill the superflous inner braces here. > + * Return: 0 or -ERRNO with one of the following status codes: Maybe s...

On Mon, Jan 13, 2020 at 02:47:01PM -0800, Ralph Campbell wrote: > diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c > index 47ad9cc89aab..4efecc0f13cb 100644 > +++ b/mm/mmu_notifier.c > @@ -1171,6 +1171,39 @@ void mmu_interval_notifier_update(struct mmu_interval_notifier *mni, > } > EXPORT_SYMBOL_GPL(mmu_interval_notifier_update); > > +struct mmu_interval_notifier

From: Jason Gunthorpe <jgg at mellanox.com> 8 of the mmu_notifier using drivers (i915_gem, radeon_mn, umem_odp, hfi1, scif_dma, vhost, gntdev, hmm) drivers are using a common pattern where they only use invalidate_range_start/end and immediately check the invalidating range against some driver data structure to tell if the driver is interested. Half of them use an interval_tree, the others

...ter. > > .. and this poses all sorts of questions about consistency with items > on the deferred list. Should find return an item undergoing deletion? I don't think so. The deferred operations are all complete when mmu_interval_read_begin() returns, and the sequence number check with mmu_interval_read_retry() guarantees there have been no changes while not holding the driver page table lock and calling hmm_range_fault(). > Should find return items using the old interval tree values or their > new updated values? > > Jason I think it should only look at the old interval tree and not the...

...nge->notifier_seq = mmu_interval_read_begin(&bo->notifier); + + down_read(&mm->mmap_sem); r = hmm_range_fault(range, 0); up_read(&mm->mmap_sem); - - if (unlikely(r < 0)) + if (unlikely(r <= 0)) { + /* + * FIXME: This timeout should encompass the retry from + * mmu_interval_read_retry() as well. + */ + if ((r == 0 || r == -EBUSY) && !time_after(jiffies, timeout)) + goto retry; goto out_free_pfns; + } for (i = 0; i < ttm->num_pages; i++) { - pages[i] = hmm_device_entry_to_page(range, pfns[i]); + /* FIXME: The pages cannot be touched outside the notifie...

One fix and a minor cleanup. Only compile-tested due to lack of HW, so I'd be happy if someone with access to HW could test. But not sure how easy this is to trigger. Likely some concurrent MADV_DONTNEED on the PTE we just converted might be able to trigger it. Cc: Karol Herbst <kherbst at redhat.com> Cc: Lyude Paul <lyude at redhat.com> Cc: Danilo Krummrich <dakr at

From: Jason Gunthorpe <jgg at mellanox.com> The API is a bit complicated for the uses we actually have, and disucssions for simplifying have come up a number of times. This small series removes the customizable pfn format and simplifies the return code of hmm_range_fault() All the drivers are adjusted to process in the simplified format. I would appreciated tested-by's for the two

...12 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages) down_read(&mm->mmap_sem); r = hmm_range_fault(range); up_read(&mm->mmap_sem); - if (unlikely(r <= 0)) { + if (unlikely(r)) { /* * FIXME: This timeout should encompass the retry from * mmu_interval_read_retry() as well. */ - if ((r == 0 || r == -EBUSY) && !time_after(jiffies, timeout)) + if ((r == -EBUSY) && !time_after(jiffies, timeout)) goto retry; goto out_free_pfns; } diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c index 645fe...

...12 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages) down_read(&mm->mmap_sem); r = hmm_range_fault(range); up_read(&mm->mmap_sem); - if (unlikely(r <= 0)) { + if (unlikely(r)) { /* * FIXME: This timeout should encompass the retry from * mmu_interval_read_retry() as well. */ - if ((r == 0 || r == -EBUSY) && !time_after(jiffies, timeout)) + if (r == -EBUSY && !time_after(jiffies, timeout)) goto retry; goto out_free_pfns; } diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c index 645fedd...

...goto again; - } - hmm_range_unregister(&range); + if (ret == -EBUSY) + goto again; return ret; } + up_read(&mm->mmap_sem); + take_lock(driver->update); - if (!hmm_range_valid(&range)) { + if (mmu_interval_read_retry(&ni, range.notifier_seq) { release_lock(driver->update); - up_read(&mm->mmap_sem); goto again; } - // Use pfns array content to update device page table + /* Use pfns array content to update device page table, + * under the updat...

...m_pfns = kvmalloc_array(ttm->num_pages, + sizeof(*range->hmm_pfns), GFP_KERNEL); + if (unlikely(!range->hmm_pfns)) { r = -ENOMEM; goto out_free_ranges; } @@ -867,7 +853,7 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages) * the notifier_lock, and mmu_interval_read_retry() must be done first. */ for (i = 0; i < ttm->num_pages; i++) - pages[i] = hmm_device_entry_to_page(range, range->pfns[i]); + pages[i] = hmm_pfn_to_page(range->hmm_pfns[i]); gtt->range = range; mmput(mm); @@ -877,7 +863,7 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu...

...m_pfns = kvmalloc_array(ttm->num_pages, + sizeof(*range->hmm_pfns), GFP_KERNEL); + if (unlikely(!range->hmm_pfns)) { r = -ENOMEM; goto out_free_ranges; } @@ -867,7 +853,7 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages) * the notifier_lock, and mmu_interval_read_retry() must be done first. */ for (i = 0; i < ttm->num_pages; i++) - pages[i] = hmm_device_entry_to_page(range, range->pfns[i]); + pages[i] = hmm_pfn_to_page(range->hmm_pfns[i]); gtt->range = range; mmput(mm); @@ -877,7 +863,7 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu...

From: Jason Gunthorpe <jgg at mellanox.com> The API is a bit complicated for the uses we actually have, and disucssions for simplifying have come up a number of times. This small series removes the customizable pfn format and simplifies the return code of hmm_range_fault() All the drivers are adjusted to process in the simplified format. I would appreciated tested-by's for the two

..._pages, > + sizeof(*range->hmm_pfns), GFP_KERNEL); > + if (unlikely(!range->hmm_pfns)) { > r = -ENOMEM; > goto out_free_ranges; > } > @@ -867,7 +853,7 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages) > * the notifier_lock, and mmu_interval_read_retry() must be done first. > */ > for (i = 0; i < ttm->num_pages; i++) > - pages[i] = hmm_device_entry_to_page(range, range->pfns[i]); > + pages[i] = hmm_pfn_to_page(range->hmm_pfns[i]); > > gtt->range = range; > mmput(mm); > @@ -877,7 +863,7 @@ int am...

This series adds new functions to the mmu interval notifier API to allow device drivers with MMUs to dynamically mirror a process' page tables based on device faults and invalidation callbacks. The Nouveau driver is updated to use the extended API and a set of stand alone self tests is added to help validate and maintain correctness. The patches are based on linux-5.5.0-rc6 and are for