> 在 2018年3月5日，上午10:52，Yan, Zheng <zyan@xxxxxxxxxx> 写道：
>
>
>
>> On 24 Feb 2018, at 18:35, Chengguang Xu <cgxu519@xxxxxxxxxx> wrote:
>>
>> When setting high volume of caps_min_count or having many
>> unreserved caps, unused caps may always keep in the ->caps_list
>> even can't get new cap from kmem_cache_alloc because lack of
>> maximum limitation of caps_avail_count. Hence reuse caps in
>> ->caps_list if available, it's maybe better than setting max
>> limitation of caps_avail_count and releasing unused caps when
>> reaching the limit.
>>
>> Signed-off-by: Chengguang Xu <cgxu519@xxxxxxxxxx>
>> ---
>> Only compile tested.
>>
>> fs/ceph/caps.c | 17 +++++++++++++++++
>> 1 file changed, 17 insertions(+)
>>
>> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
>> index 6582c45..b598a24 100644
>> --- a/fs/ceph/caps.c
>> +++ b/fs/ceph/caps.c
>> @@ -280,6 +280,23 @@ struct ceph_cap *ceph_get_cap(struct ceph_mds_client *mdsc,
>> /* temporary, until we do something about cap import/export */
>> if (!ctx) {
>> cap = kmem_cache_alloc(ceph_cap_cachep, GFP_NOFS);
>> + if (!cap) {
>> + spin_lock(&mdsc->caps_list_lock);
>> + if (mdsc->caps_avail_count) {
>> + BUG_ON(list_empty(&mdsc->caps_list));
>> +
>> + mdsc->caps_avail_count--;
>> + mdsc->caps_use_count++;
>> + cap = list_first_entry(&mdsc->caps_list,
>> + struct ceph_cap, caps_item);
>> + list_del(&cap->caps_item);
>> +
>> + BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
>> + mdsc->caps_reserve_count + mdsc->caps_avail_count);
>> + }
>> + spin_unlock(&mdsc->caps_list_lock);
>> + }
>> +
>
> should skip executing following code. I fixed it locally
Yes, that should be in else part. Thanks for your fix.
>
>> if (cap) {
>> spin_lock(&mdsc->caps_list_lock);
>> mdsc->caps_use_count++;
>> --
>> 1.8.3.1
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