On 2017/11/3 18:33, Yunlei He wrote:
> This path separate nat_entry mem alloc from nat_tree_lock,
> which will benefit in some low mem case.>
> Signed-off-by: Yunlei He <heyun...@huawei.com>
> ---
> fs/f2fs/node.c | 48 +++++++++++++++++++++++++++++++++---------------
> 1 file changed, 33 insertions(+), 15 deletions(-)
>
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index fef5c68..5adefea 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -257,22 +257,15 @@ static struct nat_entry *grab_nat_entry(struct
> f2fs_nm_info *nm_i, nid_t nid,
>
> if (no_fail) {
> new = f2fs_kmem_cache_alloc(nat_entry_slab, GFP_NOFS);
> - f2fs_radix_tree_insert(&nm_i->nat_root, nid, new);
> } else {
> new = kmem_cache_alloc(nat_entry_slab, GFP_NOFS);
> if (!new)
> return NULL;
> - if (radix_tree_insert(&nm_i->nat_root, nid, new)) {
> - kmem_cache_free(nat_entry_slab, new);
> - return NULL;
> - }
> }
>
> memset(new, 0, sizeof(struct nat_entry));
> nat_set_nid(new, nid);
> nat_reset_flag(new);
> - list_add_tail(&new->list, &nm_i->nat_entries);
> - nm_i->nat_cnt++;
> return new;
> }
>
> @@ -281,18 +274,36 @@ static void cache_nat_entry(struct f2fs_sb_info *sbi,
> nid_t nid,
> {
> struct f2fs_nm_info *nm_i = NM_I(sbi);
> struct nat_entry *e;
> + struct nat_entry *e_new = grab_nat_entry(nm_i, nid, false);
rename e_new to new to keep the coding style?
>
> + radix_tree_preload(GFP_NOFS | __GFP_NOFAIL);
__GFP_NOFAIL make preloading not fail, so if our optimization scenario
aimed at low memory, what about avoiding preload?
> + down_write(&nm_i->nat_tree_lock);
> e = __lookup_nat_cache(nm_i, nid);
> if (!e) {
> - e = grab_nat_entry(nm_i, nid, false);
> - if (e)
> - node_info_from_raw_nat(&e->ni, ne);
> + if (!e_new) {
> + up_write(&nm_i->nat_tree_lock);
move this to bottom?
> + return;
goto out;
> + }
> +
> + if (radix_tree_insert(&nm_i->nat_root, nid, e_new)) {
> + kmem_cache_free(nat_entry_slab, e_new);
> + radix_tree_preload_end();> +
> up_write(&nm_i->nat_tree_lock)> + return;
ditto
> + }
> +
> + radix_tree_preload_end();> +
> list_add_tail(&e_new->list, &nm_i->nat_entries);
> + nm_i->nat_cnt++;
> + node_info_from_raw_nat(&e_new->ni, ne);
> } else {
> f2fs_bug_on(sbi, nat_get_ino(e) != le32_to_cpu(ne->ino) ||
> nat_get_blkaddr(e) !=
> le32_to_cpu(ne->block_addr) ||
> nat_get_version(e) != ne->version);
> + kmem_cache_free(nat_entry_slab, e_new);
> }
out:
> + up_write(&nm_i->nat_tree_lock);> }
>
> static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
> @@ -300,13 +311,17 @@ static void set_node_addr(struct f2fs_sb_info *sbi,
> struct node_info *ni,
> {
> struct f2fs_nm_info *nm_i = NM_I(sbi);
> struct nat_entry *e;
> + struct nat_entry *e_new = grab_nat_entry(nm_i, ni->nid, true);
>
> down_write(&nm_i->nat_tree_lock);
> e = __lookup_nat_cache(nm_i, ni->nid);
> if (!e) {
> - e = grab_nat_entry(nm_i, ni->nid, true);
> - copy_node_info(&e->ni, ni);
e = new
> + f2fs_radix_tree_insert(&nm_i->nat_root, ni->nid, e_new);
> + list_add_tail(&e_new->list, &nm_i->nat_entries);
> + nm_i->nat_cnt++;
> + copy_node_info(&e_new->ni, ni);
> f2fs_bug_on(sbi, ni->blk_addr == NEW_ADDR);
> + e = e_new;
> } else if (new_blkaddr == NEW_ADDR) {
> /*
> * when nid is reallocated,
> @@ -315,7 +330,9 @@ static void set_node_addr(struct f2fs_sb_info *sbi,
> struct node_info *ni,
> */
> copy_node_info(&e->ni, ni);
> f2fs_bug_on(sbi, ni->blk_addr != NULL_ADDR);
> - }
> + kmem_cache_free(nat_entry_slab, e_new);
> + } else
} else {
kmem_cache_free(nat_entry_slab, e_new);
}
Thanks,
> + kmem_cache_free(nat_entry_slab, e_new);
>
> /* sanity check */
> f2fs_bug_on(sbi, nat_get_blkaddr(e) != ni->blk_addr);
> @@ -424,9 +441,7 @@ void get_node_info(struct f2fs_sb_info *sbi, nid_t nid,
> struct node_info *ni)
> f2fs_put_page(page, 1);
> cache:
> /* cache nat entry */
> - down_write(&nm_i->nat_tree_lock);
> cache_nat_entry(sbi, nid, &ne);
> - up_write(&nm_i->nat_tree_lock);
> }
>
> /*
> @@ -2375,6 +2390,9 @@ static void remove_nats_in_journal(struct f2fs_sb_info
> *sbi)
> ne = __lookup_nat_cache(nm_i, nid);
> if (!ne) {
> ne = grab_nat_entry(nm_i, nid, true);
> + f2fs_radix_tree_insert(&nm_i->nat_root, nid, ne);
> + list_add_tail(&ne->list, &nm_i->nat_entries);
> + nm_i->nat_cnt++;
> node_info_from_raw_nat(&ne->ni, &raw_ne);
> }
>
>
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