On 6/15/21 7:49 AM, Coly Li wrote:
> From: Jianpeng Ma <jianpeng.ma@xxxxxxxxx>
>
> This patch implements the bch_nvm_alloc_pages() of the buddy.
> In terms of function, this func is like current-page-buddy-alloc.
> But the differences are:
> a: it need owner_uuid as parameter which record owner info. And it
> make those info persistence.
> b: it don't need flags like GFP_*. All allocs are the equal.
> c: it don't trigger other ops etc swap/recycle.
>
> Signed-off-by: Jianpeng Ma <jianpeng.ma@xxxxxxxxx>
> Co-developed-by: Qiaowei Ren <qiaowei.ren@xxxxxxxxx>
> Signed-off-by: Qiaowei Ren <qiaowei.ren@xxxxxxxxx>
> Signed-off-by: Coly Li <colyli@xxxxxxx>
> ---
> drivers/md/bcache/nvm-pages.c | 174 ++++++++++++++++++++++++++++++++
> drivers/md/bcache/nvm-pages.h | 6 ++
> include/uapi/linux/bcache-nvm.h | 6 +-
> 3 files changed, 184 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/md/bcache/nvm-pages.c b/drivers/md/bcache/nvm-pages.c
> index 804ee66e97be..5d095d241483 100644
> --- a/drivers/md/bcache/nvm-pages.c
> +++ b/drivers/md/bcache/nvm-pages.c
> @@ -74,6 +74,180 @@ static inline void remove_owner_space(struct bch_nvm_namespace *ns,
> }
> }
>
> +/* If not found, it will create if create == true */
> +static struct bch_nvm_pages_owner_head *find_owner_head(const char *owner_uuid, bool create)
> +{
> + struct bch_owner_list_head *owner_list_head = only_set->owner_list_head;
> + struct bch_nvm_pages_owner_head *owner_head = NULL;
> + int i;
> +
> + if (owner_list_head == NULL)
> + goto out;
> +
> + for (i = 0; i < only_set->owner_list_used; i++) {
> + if (!memcmp(owner_uuid, owner_list_head->heads[i].uuid, 16)) {
> + owner_head = &(owner_list_head->heads[i]);
> + break;
> + }
> + }
> +
Please, don't name is 'heads'. If this is supposed to be a linked list,
use the standard list implementation and initialize the pointers correctly.
If it isn't use an array (as you know in advance how many array entries
you can allocate).
> + if (!owner_head && create) {
> + u32 used = only_set->owner_list_used;
> +
> + if (only_set->owner_list_size > used) {
> + memcpy_flushcache(owner_list_head->heads[used].uuid, owner_uuid, 16);
> + only_set->owner_list_used++;
> +
> + owner_list_head->used++;
> + owner_head = &(owner_list_head->heads[used]);
> + } else
> + pr_info("no free bch_nvm_pages_owner_head\n");
> + }
> +
> +out:
> + return owner_head;
> +}
> +
> +static struct bch_nvm_pgalloc_recs *find_empty_pgalloc_recs(void)
> +{
> + unsigned int start;
> + struct bch_nvm_namespace *ns = only_set->nss[0];
> + struct bch_nvm_pgalloc_recs *recs;
> +
> + start = bitmap_find_next_zero_area(ns->pgalloc_recs_bitmap, BCH_MAX_PGALLOC_RECS, 0, 1, 0);
> + if (start > BCH_MAX_PGALLOC_RECS) {
> + pr_info("no free struct bch_nvm_pgalloc_recs\n");
> + return NULL;
> + }
> +
> + bitmap_set(ns->pgalloc_recs_bitmap, start, 1);
> + recs = (struct bch_nvm_pgalloc_recs *)(ns->kaddr + BCH_NVM_PAGES_SYS_RECS_HEAD_OFFSET)
> + + start;
> + return recs;
> +}
> +
> +static struct bch_nvm_pgalloc_recs *find_nvm_pgalloc_recs(struct bch_nvm_namespace *ns,
> + struct bch_nvm_pages_owner_head *owner_head, bool create)
> +{
> + int ns_nr = ns->sb->this_namespace_nr;
> + struct bch_nvm_pgalloc_recs *prev_recs = NULL, *recs = owner_head->recs[ns_nr];
> +
> + /* If create=false, we return recs[nr] */
> + if (!create)
> + return recs;
> +
> + /*
> + * If create=true, it mean we need a empty struct bch_pgalloc_rec
> + * So we should find non-empty struct bch_nvm_pgalloc_recs or alloc
> + * new struct bch_nvm_pgalloc_recs. And return this bch_nvm_pgalloc_recs
> + */
> + while (recs && (recs->used == recs->size)) {
> + prev_recs = recs;
> + recs = recs->next;
> + }
> +
> + /* Found empty struct bch_nvm_pgalloc_recs */
> + if (recs)
> + return recs;
> + /* Need alloc new struct bch_nvm_galloc_recs */
> + recs = find_empty_pgalloc_recs();
> + if (recs) {
> + recs->next = NULL;
> + recs->owner = owner_head;
> + memcpy_flushcache(recs->magic, bch_nvm_pages_pgalloc_magic, 16);
> + memcpy_flushcache(recs->owner_uuid, owner_head->uuid, 16);
> + recs->size = BCH_MAX_RECS;
> + recs->used = 0;
> +
> + if (prev_recs)
> + prev_recs->next = recs;
> + else
> + owner_head->recs[ns_nr] = recs;
> + }
> +
Wouldn't it be easier if the bitmap covers the entire range, and not
just the non-empty ones?
Eventually (ie if the NVM set becomes full) it'll cover it anyway, so
can't we save ourselves some time to allocate a large enough bitmap
upfront and only use it do figure out empty recs?
> + return recs;
> +}
> +
> +static void add_pgalloc_rec(struct bch_nvm_pgalloc_recs *recs, void *kaddr, int order)
> +{
> + int i;
> +
> + for (i = 0; i < recs->size; i++) {
> + if (recs->recs[i].pgoff == 0) {
> + recs->recs[i].pgoff = (unsigned long)kaddr >> PAGE_SHIFT;
> + recs->recs[i].order = order;
> + recs->used++;
> + break;
> + }
> + }
> + BUG_ON(i == recs->size);
> +}
> +
> +void *bch_nvm_alloc_pages(int order, const char *owner_uuid)
> +{
> + void *kaddr = NULL;
> + struct bch_nvm_pgalloc_recs *pgalloc_recs;
> + struct bch_nvm_pages_owner_head *owner_head;
> + int i, j;
> +
> + mutex_lock(&only_set->lock);
> + owner_head = find_owner_head(owner_uuid, true);
> +
> + if (!owner_head) {
> + pr_err("can't find bch_nvm_pgalloc_recs by(uuid=%s)\n", owner_uuid);
> + goto unlock;
> + }
> +
> + for (j = 0; j < only_set->total_namespaces_nr; j++) {
> + struct bch_nvm_namespace *ns = only_set->nss[j];
> +
> + if (!ns || (ns->free < (1L << order)))
> + continue;
> +
> + for (i = order; i < BCH_MAX_ORDER; i++) {
> + struct list_head *list;
> + struct page *page, *buddy_page;
> +
> + if (list_empty(&ns->free_area[i]))
> + continue;
> +
> + list = ns->free_area[i].next;
list_first_entry()?
> + page = container_of((void *)list, struct page, zone_device_data);
> +
> + list_del(list);
> +
> + while (i != order) {
> + buddy_page = nvm_vaddr_to_page(ns,
> + nvm_pgoff_to_vaddr(ns, page->index + (1L << (i - 1))));
> + set_page_private(buddy_page, i - 1);
> + buddy_page->index = page->index + (1L << (i - 1));
> + __SetPageBuddy(buddy_page);
> + list_add((struct list_head *)&buddy_page->zone_device_data,
> + &ns->free_area[i - 1]);
> + i--;
> + }
> +
> + set_page_private(page, order);
> + __ClearPageBuddy(page);
> + ns->free -= 1L << order;
> + kaddr = nvm_pgoff_to_vaddr(ns, page->index);
> + break;
> + }
> +
> + if (i < BCH_MAX_ORDER) {
> + pgalloc_recs = find_nvm_pgalloc_recs(ns, owner_head, true);
> + /* ToDo: handle pgalloc_recs==NULL */
> + add_pgalloc_rec(pgalloc_recs, kaddr, order);
> + break;
> + }
> + }
> +
> +unlock:
> + mutex_unlock(&only_set->lock);
> + return kaddr;
> +}
> +EXPORT_SYMBOL_GPL(bch_nvm_alloc_pages);
> +
> #define BCH_PGOFF_TO_KVADDR(pgoff) ((void *)((unsigned long)pgoff << PAGE_SHIFT))
>
> static int init_owner_info(struct bch_nvm_namespace *ns)
> diff --git a/drivers/md/bcache/nvm-pages.h b/drivers/md/bcache/nvm-pages.h
> index 71beb244b9be..f2583723aca6 100644
> --- a/drivers/md/bcache/nvm-pages.h
> +++ b/drivers/md/bcache/nvm-pages.h
> @@ -62,6 +62,7 @@ extern struct bch_nvm_set *only_set;
> struct bch_nvm_namespace *bch_register_namespace(const char *dev_path);
> int bch_nvm_init(void);
> void bch_nvm_exit(void);
> +void *bch_nvm_alloc_pages(int order, const char *owner_uuid);
>
> #else
>
> @@ -74,6 +75,11 @@ static inline int bch_nvm_init(void)
> return 0;
> }
> static inline void bch_nvm_exit(void) { }
> +static inline void *bch_nvm_alloc_pages(int order, const char *owner_uuid)
> +{
> + return NULL;
> +}
> +
>
> #endif /* CONFIG_BCACHE_NVM_PAGES */
>
> diff --git a/include/uapi/linux/bcache-nvm.h b/include/uapi/linux/bcache-nvm.h
> index 1fdb3eaabf7e..9cb937292202 100644
> --- a/include/uapi/linux/bcache-nvm.h
> +++ b/include/uapi/linux/bcache-nvm.h
> @@ -135,9 +135,11 @@ union {
> offsetof(struct bch_nvm_pgalloc_recs, recs)) / \
> sizeof(struct bch_pgalloc_rec))
>
> +/* Currently 64 struct bch_nvm_pgalloc_recs is enough */
> #define BCH_MAX_PGALLOC_RECS \
> - ((BCH_NVM_PAGES_OFFSET - BCH_NVM_PAGES_SYS_RECS_HEAD_OFFSET) / \
> - sizeof(struct bch_nvm_pgalloc_recs))
> + (min_t(unsigned int, 64, \
> + (BCH_NVM_PAGES_OFFSET - BCH_NVM_PAGES_SYS_RECS_HEAD_OFFSET) / \
> + sizeof(struct bch_nvm_pgalloc_recs)))
>
> struct bch_nvm_pages_owner_head {
> unsigned char uuid[16];
>
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer
