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Message-ID: <CAJuCfpEsVE7Jae7PqWvgTtm38C5MPFx43+dDyYzfKLMQFuE_3A@mail.gmail.com>
Date: Fri, 22 Aug 2025 09:56:41 -0700
From: Suren Baghdasaryan <surenb@...gle.com>
To: Vlastimil Babka <vbabka@...e.cz>
Cc: "Liam R. Howlett" <Liam.Howlett@...cle.com>, Christoph Lameter <cl@...two.org>,
David Rientjes <rientjes@...gle.com>, Roman Gushchin <roman.gushchin@...ux.dev>,
Harry Yoo <harry.yoo@...cle.com>, Uladzislau Rezki <urezki@...il.com>, linux-mm@...ck.org,
linux-kernel@...r.kernel.org, rcu@...r.kernel.org,
maple-tree@...ts.infradead.org
Subject: Re: [PATCH v5 06/14] tools: Add sheaves support to testing infrastructure
On Wed, Jul 23, 2025 at 6:35 AM Vlastimil Babka <vbabka@...e.cz> wrote:
>
> From: "Liam R. Howlett" <Liam.Howlett@...cle.com>
>
> Allocate a sheaf and fill it to the count amount. Does not fill to the
> sheaf limit to detect incorrect allocation requests.
>
> Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
> Signed-off-by: Vlastimil Babka <vbabka@...e.cz>
> ---
> tools/include/linux/slab.h | 24 +++++++++++++
> tools/testing/shared/linux.c | 84 ++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 108 insertions(+)
>
> diff --git a/tools/include/linux/slab.h b/tools/include/linux/slab.h
> index d1444e79f2685edb828adbce8b3fbb500c0f8844..1962d7f1abee154e1cda5dba28aef213088dd198 100644
> --- a/tools/include/linux/slab.h
> +++ b/tools/include/linux/slab.h
> @@ -23,6 +23,13 @@ enum slab_state {
> FULL
> };
>
> +struct slab_sheaf {
> + struct kmem_cache *cache;
> + unsigned int size;
> + unsigned int capacity;
> + void *objects[];
> +};
> +
> struct kmem_cache_args {
> unsigned int align;
> unsigned int sheaf_capacity;
> @@ -80,4 +87,21 @@ void kmem_cache_free_bulk(struct kmem_cache *cachep, size_t size, void **list);
> int kmem_cache_alloc_bulk(struct kmem_cache *cachep, gfp_t gfp, size_t size,
> void **list);
>
> +struct slab_sheaf *
> +kmem_cache_prefill_sheaf(struct kmem_cache *s, gfp_t gfp, unsigned int size);
> +
> +void *
> +kmem_cache_alloc_from_sheaf(struct kmem_cache *s, gfp_t gfp,
> + struct slab_sheaf *sheaf);
> +
> +void kmem_cache_return_sheaf(struct kmem_cache *s, gfp_t gfp,
> + struct slab_sheaf *sheaf);
> +int kmem_cache_refill_sheaf(struct kmem_cache *s, gfp_t gfp,
> + struct slab_sheaf **sheafp, unsigned int size);
> +
> +static inline unsigned int kmem_cache_sheaf_size(struct slab_sheaf *sheaf)
> +{
> + return sheaf->size;
> +}
> +
> #endif /* _TOOLS_SLAB_H */
> diff --git a/tools/testing/shared/linux.c b/tools/testing/shared/linux.c
> index f998555a1b2af4a899a468a652b04622df459ed3..e0255f53159bd3a1325d49192283dd6790a5e3b8 100644
> --- a/tools/testing/shared/linux.c
> +++ b/tools/testing/shared/linux.c
> @@ -181,6 +181,12 @@ int kmem_cache_alloc_bulk(struct kmem_cache *cachep, gfp_t gfp, size_t size,
> if (kmalloc_verbose)
> pr_debug("Bulk alloc %zu\n", size);
>
> + if (cachep->exec_callback) {
> + if (cachep->callback)
> + cachep->callback(cachep->private);
> + cachep->exec_callback = false;
> + }
> +
> pthread_mutex_lock(&cachep->lock);
> if (cachep->nr_objs >= size) {
> struct radix_tree_node *node;
> @@ -270,6 +276,84 @@ __kmem_cache_create_args(const char *name, unsigned int size,
> return ret;
> }
>
> +struct slab_sheaf *
> +kmem_cache_prefill_sheaf(struct kmem_cache *s, gfp_t gfp, unsigned int size)
> +{
> + struct slab_sheaf *sheaf;
> + unsigned int capacity;
> +
> + if (size > s->sheaf_capacity)
> + capacity = size;
> + else
> + capacity = s->sheaf_capacity;
nit:
capacity = max(size, s->sheaf_capacity);
> +
> + sheaf = malloc(sizeof(*sheaf) + sizeof(void *) * s->sheaf_capacity * capacity);
Should this really be `sizeof(void *) * s->sheaf_capacity * capacity`
or just `sizeof(void *) * capacity` ?
> + if (!sheaf) {
> + return NULL;
> + }
> +
> + memset(sheaf, 0, size);
> + sheaf->cache = s;
> + sheaf->capacity = capacity;
> + sheaf->size = kmem_cache_alloc_bulk(s, gfp, size, sheaf->objects);
> + if (!sheaf->size) {
> + free(sheaf);
> + return NULL;
> + }
> +
> + return sheaf;
> +}
> +
> +int kmem_cache_refill_sheaf(struct kmem_cache *s, gfp_t gfp,
> + struct slab_sheaf **sheafp, unsigned int size)
> +{
> + struct slab_sheaf *sheaf = *sheafp;
> + int refill;
> +
> + if (sheaf->size >= size)
> + return 0;
> +
> + if (size > sheaf->capacity) {
> + sheaf = kmem_cache_prefill_sheaf(s, gfp, size);
> + if (!sheaf)
> + return -ENOMEM;
> +
> + kmem_cache_return_sheaf(s, gfp, *sheafp);
> + *sheafp = sheaf;
> + return 0;
> + }
> +
> + refill = kmem_cache_alloc_bulk(s, gfp, size - sheaf->size,
> + &sheaf->objects[sheaf->size]);
> + if (!refill)
> + return -ENOMEM;
> +
> + sheaf->size += refill;
> + return 0;
> +}
> +
> +void kmem_cache_return_sheaf(struct kmem_cache *s, gfp_t gfp,
> + struct slab_sheaf *sheaf)
> +{
> + if (sheaf->size) {
> + //s->non_kernel += sheaf->size;
Above comment seems obsolete.
> + kmem_cache_free_bulk(s, sheaf->size, &sheaf->objects[0]);
> + }
> + free(sheaf);
> +}
> +
> +void *
> +kmem_cache_alloc_from_sheaf(struct kmem_cache *s, gfp_t gfp,
> + struct slab_sheaf *sheaf)
> +{
> + if (sheaf->size == 0) {
> + printf("Nothing left in sheaf!\n");
> + return NULL;
> + }
> +
Should we clear sheaf->objects[sheaf->size] for additional safety?
> + return sheaf->objects[--sheaf->size];
> +}
> +
> /*
> * Test the test infrastructure for kem_cache_alloc/free and bulk counterparts.
> */
>
> --
> 2.50.1
>
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