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cachefiles: narrow the scope of triggering EPOLLIN events in ondemand mode

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Don't trigger EPOLLIN when there are only reopening read requests in
xarray.

Suggested-by: Xin Yin <yinxin.x@bytedance.com>
Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com>
Link: https://lore.kernel.org/r/20231120041422.75170-5-zhujia.zj@bytedance.com
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Jia Zhu 2023-11-20 12:14:21 +08:00 committed by Christian Brauner
parent 0a7e54c195
commit b817e22b2e
No known key found for this signature in database
GPG key ID: 91C61BC06578DCA2
2 changed files with 24 additions and 2 deletions
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14
fs/cachefiles/daemon.c
View file

@ -355,14 +355,24 @@ static __poll_t cachefiles_daemon_poll(struct file *file,
struct poll_table_struct *poll)
{
struct cachefiles_cache *cache = file->private_data;
XA_STATE(xas, &cache->reqs, 0);
struct cachefiles_req *req;
__poll_t mask;
poll_wait(file, &cache->daemon_pollwq, poll);
mask = 0;
if (cachefiles_in_ondemand_mode(cache)) {
if (!xa_empty(&cache->reqs))
mask |= EPOLLIN;
if (!xa_empty(&cache->reqs)) {
rcu_read_lock();
xas_for_each_marked(&xas, req, ULONG_MAX, CACHEFILES_REQ_NEW) {
if (!cachefiles_ondemand_is_reopening_read(req)) {
mask |= EPOLLIN;
break;
}
}
rcu_read_unlock();
}
} else {
if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
mask |= EPOLLIN;

12
fs/cachefiles/internal.h
View file

@ -329,6 +329,13 @@ cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \
CACHEFILES_OBJECT_STATE_FUNCS(open, OPEN);
CACHEFILES_OBJECT_STATE_FUNCS(close, CLOSE);
CACHEFILES_OBJECT_STATE_FUNCS(reopening, REOPENING);
static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req *req)
{
return cachefiles_ondemand_object_is_reopening(req->object) &&
req->msg.opcode == CACHEFILES_OP_READ;
}
#else
static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
char __user *_buffer, size_t buflen)
@ -359,6 +366,11 @@ static inline int cachefiles_ondemand_init_obj_info(struct cachefiles_object *ob
static inline void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj)
{
}
static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req *req)
{
return false;
}
#endif
/*