Re: [PATCH V4 4/5] cachefiles: narrow the scope of triggering EPOLLIN events in ondemand mode

[David Howells]

Jia Zhu <zhujia.zj@xxxxxxxxxxxxx> wrote:

> +		if (!xa_empty(xa)) {
> +			xa_lock(xa);
> +			xa_for_each_marked(xa, index, req, CACHEFILES_REQ_NEW) {
> +				if (!cachefiles_ondemand_is_reopening_read(req)) {
> +					mask |= EPOLLIN;
> +					break;
> +				}
> +			}
> +			xa_unlock(xa);
> +		}

I wonder if there's a more efficient way to do this.  I guess it depends on
how many reqs you expect to get in a queue.  It might be worth taking the
rcu_read_lock before calling xa_lock() and holding it over the whole loop.

David