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charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu The list_head member of struct hyp_page is only needed when the page is attached to a free-list, which by definition implies the page is free. As such, nothing prevents us from using the page itself to store the list_head, hence reducing the size of the vmemmap. Signed-off-by: Quentin Perret --- arch/arm64/kvm/hyp/include/nvhe/memory.h | 1 - arch/arm64/kvm/hyp/nvhe/page_alloc.c | 39 ++++++++++++++++++++---- 2 files changed, 33 insertions(+), 7 deletions(-) diff --git a/arch/arm64/kvm/hyp/include/nvhe/memory.h b/arch/arm64/kvm/hyp/include/nvhe/memory.h index fd78bde939ee..7691ab495eb4 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/memory.h +++ b/arch/arm64/kvm/hyp/include/nvhe/memory.h @@ -12,7 +12,6 @@ struct hyp_page { unsigned int refcount; unsigned int order; struct hyp_pool *pool; - struct list_head node; }; extern u64 __hyp_vmemmap; diff --git a/arch/arm64/kvm/hyp/nvhe/page_alloc.c b/arch/arm64/kvm/hyp/nvhe/page_alloc.c index 2602577daa00..34f0eb026dd2 100644 --- a/arch/arm64/kvm/hyp/nvhe/page_alloc.c +++ b/arch/arm64/kvm/hyp/nvhe/page_alloc.c @@ -62,6 +62,34 @@ static struct hyp_page *__find_buddy_avail(struct hyp_pool *pool, } +/* + * Pages that are available for allocation are tracked in free-lists, so we use + * the pages themselves to store the list nodes to avoid wasting space. As the + * allocator always returns zeroed pages (which are zeroed on the hyp_put_page() + * path to optimize allocation speed), we also need to clean-up the list node in + * each page when we take it out of the list. + */ +static inline void page_remove_from_list(struct hyp_page *p) +{ + struct list_head *node = hyp_page_to_virt(p); + + __list_del_entry(node); + memset(node, 0, sizeof(*node)); +} + +static inline void page_add_to_list(struct hyp_page *p, struct list_head *head) +{ + struct list_head *node = hyp_page_to_virt(p); + + INIT_LIST_HEAD(node); + list_add_tail(node, head); +} + +static inline struct hyp_page *node_to_page(struct list_head *node) +{ + return hyp_virt_to_page(node); +} + static void __hyp_attach_page(struct hyp_pool *pool, struct hyp_page *p) { @@ -83,14 +111,14 @@ static void __hyp_attach_page(struct hyp_pool *pool, break; /* Take the buddy out of its list, and coallesce with @p */ - list_del_init(&buddy->node); + page_remove_from_list(buddy); buddy->order = HYP_NO_ORDER; p = min(p, buddy); } /* Mark the new head, and insert it */ p->order = order; - list_add_tail(&p->node, &pool->free_area[order]); + page_add_to_list(p, &pool->free_area[order]); } static struct hyp_page *__hyp_extract_page(struct hyp_pool *pool, @@ -99,7 +127,7 @@ static struct hyp_page *__hyp_extract_page(struct hyp_pool *pool, { struct hyp_page *buddy; - list_del_init(&p->node); + page_remove_from_list(p); while (p->order > order) { /* * The buddy of order n - 1 currently has HYP_NO_ORDER as it @@ -110,7 +138,7 @@ static struct hyp_page *__hyp_extract_page(struct hyp_pool *pool, p->order--; buddy = __find_buddy_nocheck(pool, p, p->order); buddy->order = p->order; - list_add_tail(&buddy->node, &pool->free_area[buddy->order]); + page_add_to_list(buddy, &pool->free_area[buddy->order]); } return p; @@ -182,7 +210,7 @@ void *hyp_alloc_pages(struct hyp_pool *pool, unsigned int order) } /* Extract it from the tree at the right order */ - p = list_first_entry(&pool->free_area[i], struct hyp_page, node); + p = node_to_page(pool->free_area[i].next); p = __hyp_extract_page(pool, p, order); hyp_set_page_refcounted(p); @@ -210,7 +238,6 @@ int hyp_pool_init(struct hyp_pool *pool, u64 pfn, unsigned int nr_pages, for (i = 0; i < nr_pages; i++) { p[i].pool = pool; p[i].order = 0; - INIT_LIST_HEAD(&p[i].node); hyp_set_page_refcounted(&p[i]); } -- 2.32.0.rc0.204.g9fa02ecfa5-goog _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm