Commit ec131b2d authored by Jérôme Glisse's avatar Jérôme Glisse Committed by Linus Torvalds
Browse files

mm/hmm: invalidate device page table at start of invalidation 

Invalidate device page table at start of invalidation and invalidate in
progress CPU page table snapshooting at both start and end of any
invalidation.

This is helpful when device need to dirty page because the device page
table report the page as dirty.  Dirtying page must happen in the start
mmu notifier callback and not in the end one.

Link: http://lkml.kernel.org/r/20181019160442.18723-7-jglisse@redhat.com


Signed-off-by: default avatarJérôme Glisse <jglisse@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 44532d4c

mm/hmm.c

+15 −12
Original line number Diff line number Diff line
@@ -43,7 +43,6 @@ static const struct mmu_notifier_ops hmm_mmu_notifier_ops; 
 *

 * @mm: mm struct this HMM struct is bound to

 * @lock: lock protecting ranges list

 * @sequence: we track updates to the CPU page table with a sequence number

 * @ranges: list of range being snapshotted

 * @mirrors: list of mirrors for this mm

 * @mmu_notifier: mmu notifier to track updates to CPU page table
@@ -52,7 +51,6 @@ static const struct mmu_notifier_ops hmm_mmu_notifier_ops; 
struct hmm {

	struct mm_struct	*mm;

	spinlock_t		lock;

	atomic_t		sequence;

	struct list_head	ranges;

	struct list_head	mirrors;

	struct mmu_notifier	mmu_notifier;
@@ -85,7 +83,6 @@ static struct hmm *hmm_register(struct mm_struct *mm) 
		return NULL;

	INIT_LIST_HEAD(&hmm->mirrors);

	init_rwsem(&hmm->mirrors_sem);

	atomic_set(&hmm->sequence, 0);

	hmm->mmu_notifier.ops = NULL;

	INIT_LIST_HEAD(&hmm->ranges);

	spin_lock_init(&hmm->lock);
@@ -126,7 +123,7 @@ void hmm_mm_destroy(struct mm_struct *mm) 
	kfree(mm->hmm);

}



static int hmm_invalidate_range(struct hmm *hmm,

static int hmm_invalidate_range(struct hmm *hmm, bool device,

				const struct hmm_update *update)

{

	struct hmm_mirror *mirror;
@@ -147,6 +144,9 @@ static int hmm_invalidate_range(struct hmm *hmm, 
	}

	spin_unlock(&hmm->lock);



	if (!device)

		return 0;



	down_read(&hmm->mirrors_sem);

	list_for_each_entry(mirror, &hmm->mirrors, list) {

		int ret;
@@ -194,13 +194,16 @@ static int hmm_invalidate_range_start(struct mmu_notifier *mn, 
				      unsigned long end,

				      bool blockable)

{

	struct hmm_update update;

	struct hmm *hmm = mm->hmm;



	VM_BUG_ON(!hmm);



	atomic_inc(&hmm->sequence);



	return 0;

	update.start = start;

	update.end = end;

	update.event = HMM_UPDATE_INVALIDATE;

	update.blockable = blockable;

	return hmm_invalidate_range(hmm, true, &update);

}



static void hmm_invalidate_range_end(struct mmu_notifier *mn,
@@ -217,7 +220,7 @@ static void hmm_invalidate_range_end(struct mmu_notifier *mn, 
	update.end = end;

	update.event = HMM_UPDATE_INVALIDATE;

	update.blockable = true;

	hmm_invalidate_range(hmm, &update);

	hmm_invalidate_range(hmm, false, &update);

}



static const struct mmu_notifier_ops hmm_mmu_notifier_ops = {

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