Re: [PATCH 04/18] maple_tree: introduce mas_wr_store_type()

[Sidhartha Kumar]

On 6/4/24 12:07 PM, Liam R. Howlett wrote:
> * Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx> [240604 13:42]:
> > Introduce mas_wr_store_type() which will set the correct store type
> > based on a walk of the tree.
> >
> > mas_prealloc_calc() is also introduced to abstract the calculation used
> > to determine the number of nodes needed for a store operation.
> >
> > Also, add a test case to validate the ordering for store type checks is
> > correct. This test models a vma expanding and then shrinking which is part
> > of the boot process.
> >
> > mas_wr_preallocate() is introduced as a wrapper function to set the store
> > type and preallcoate enough nodes.
> >
> > Signed-off-by: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
> > ---

....................

> > diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c
> > index f1caf4bcf937..c57979de1576 100644
> > --- a/tools/testing/radix-tree/maple.c
> > +++ b/tools/testing/radix-tree/maple.c
> > @@ -36223,6 +36223,37 @@ static noinline void __init check_mtree_dup(struct maple_tree *mt)
> >   
> >   extern void test_kmem_cache_bulk(void);
> >   
> > +
> > + /* test to simulate expanding a vma from [0x7fffffffe000, 0x7ffffffff000)
> > +  * to [0x7ffde4ca1000, 0x7ffffffff000) and then shrinking the vma to
> > +  * [0x7ffde4ca1000, 0x7ffde4ca2000)
> > +  */
> > +static inline int check_vma_modification(struct maple_tree *mt)
> > +{
> > +	MA_STATE(mas, mt, 0, 0);
>
>
> Don't we need locking in here?

Ya, I think I'm also missing a mas_destroy() at the end of this function. I'll 
add mt_lock()/mt_unlock() as well as mas_destroy().

Thanks,
Sid
> > +
> > +	/* vma with old start and old end */
> > +	__mas_set_range(&mas, 0x7fffffffe000, 0x7ffffffff000 - 1);
> > +	mas_preallocate(&mas, xa_mk_value(1), GFP_KERNEL);
> > +	mas_store_prealloc(&mas, xa_mk_value(1));
> > +
> > +	/* next write occurs partly in previous range [0, 0x7fffffffe000)*/
> > +	mas_prev_range(&mas, 0);
> > +	/* expand vma to {0x7ffde4ca1000, 0x7ffffffff000) */
> > +	__mas_set_range(&mas, 0x7ffde4ca1000, 0x7ffffffff000 - 1);
> > +	mas_preallocate(&mas, xa_mk_value(1), GFP_KERNEL);
> > +	mas_store_prealloc(&mas, xa_mk_value(1));
> > +
> > +	/* shrink vma to [0x7ffde4ca1000, 7ffde4ca2000) */
> > +	__mas_set_range(&mas, 0x7ffde4ca2000, 0x7ffffffff000 - 1);
> > +	mas_preallocate(&mas, NULL, GFP_KERNEL);
> > +	mas_store_prealloc(&mas, NULL);
> > +	mt_dump(mt, mt_dump_hex);
> > +
> > +	return 0;
> > +}
> > +
> > +
> >   void farmer_tests(void)
> >   {
> >   	struct maple_node *node;
> > @@ -36230,6 +36261,10 @@ void farmer_tests(void)
> >   
> >   	mt_dump(&tree, mt_dump_dec);
> >   
> > +	mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN | MT_FLAGS_USE_RCU);
> > +	check_vma_modification(&tree);
> > +	mtree_destroy(&tree);
> > +
> >   	tree.ma_root = xa_mk_value(0);
> >   	mt_dump(&tree, mt_dump_dec);
> >   
> > --
> > 2.45.1