On 2020/5/6 23:05, Jaegeuk Kim wrote:
> On 05/06, Chao Yu wrote:
>> In f2fs_try_to_free_nids(), .nid_list_lock spinlock critical region will
>> increase as expected shrink number increase, to avoid spining other CPUs
>> for long time, it's better to implement like extent cache and nats
>> shrinker.
>>
>> Signed-off-by: Chao Yu <yuch...@huawei.com>
>> ---
>> v2:
>> - fix unlock wrong spinlock.
>> fs/f2fs/node.c | 15 +++++++++++----
>> 1 file changed, 11 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
>> index 4da0d8713df5..ad0b14f4dab8 100644
>> --- a/fs/f2fs/node.c
>> +++ b/fs/f2fs/node.c
>> @@ -2488,7 +2488,6 @@ void f2fs_alloc_nid_failed(struct f2fs_sb_info *sbi,
>> nid_t nid)
>> int f2fs_try_to_free_nids(struct f2fs_sb_info *sbi, int nr_shrink)
>> {
>> struct f2fs_nm_info *nm_i = NM_I(sbi);
>> - struct free_nid *i, *next;
>> int nr = nr_shrink;
>>
>> if (nm_i->nid_cnt[FREE_NID] <= MAX_FREE_NIDS)
>> @@ -2498,14 +2497,22 @@ int f2fs_try_to_free_nids(struct f2fs_sb_info *sbi,
>> int nr_shrink)
>> return 0;
>>
>> spin_lock(&nm_i->nid_list_lock);
>> - list_for_each_entry_safe(i, next, &nm_i->free_nid_list, list) {
>> - if (nr_shrink <= 0 ||
>> - nm_i->nid_cnt[FREE_NID] <= MAX_FREE_NIDS)
>> + while (nr_shrink) {
>> + struct free_nid *i;
>> +
>> + if (nm_i->nid_cnt[FREE_NID] <= MAX_FREE_NIDS)
>> break;
>>
>> + i = list_first_entry(&nm_i->free_nid_list,
>> + struct free_nid, list);
>> + list_del(&i->list);
>> + spin_unlock(&nm_i->nid_list_lock);
>> +
>> __remove_free_nid(sbi, i, FREE_NID);
>
> __remove_free_nid() will do list_del again. btw, how about just splitting out
Oh, my bad.
How about moving __remove_free_nid into .nid_list_lock coverage?
> given nr_shrink into multiple trials?
Like this?
while (shrink) {
batch = DEFAULT_BATCH_NUMBER; // 16
spinlock();
list_for_each_entry_safe() {
if (!shrink || !batch)
break;
remove_item_from_list;
shrink--;
batch--;
}
spin_unlock();
}
Thanks,
>
>> kmem_cache_free(free_nid_slab, i);
>> nr_shrink--;
>> +
>> + spin_lock(&nm_i->nid_list_lock);
>> }
>> spin_unlock(&nm_i->nid_list_lock);
>> mutex_unlock(&nm_i->build_lock);
>> --
>> 2.18.0.rc1
> .
>
