[Linux-cachefs] [RFC PATCH 4/5] cachefiles: narrow the scope of triggering EPOLLIN events in ondemand mode

[Jia Zhu]

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

Suggested-by: Xin Yin <yinxi...@bytedance.com>
Signed-off-by: Jia Zhu <zhujia...@bytedance.com>
---
 fs/cachefiles/daemon.c   | 13 +++++++++++--
 fs/cachefiles/internal.h | 12 ++++++++++++
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
index aa4efcabb5e3..c74bd1f4ecf5 100644
--- a/fs/cachefiles/daemon.c
+++ b/fs/cachefiles/daemon.c
@@ -355,14 +355,23 @@ static __poll_t cachefiles_daemon_poll(struct file *file,
                                           struct poll_table_struct *poll)
 {
        struct cachefiles_cache *cache = file->private_data;
+       struct xarray *xa = &cache->reqs;
+       struct cachefiles_req *req;
+       unsigned long index;
        __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(xa)) {
+                       xa_for_each_marked(xa, index, req, CACHEFILES_REQ_NEW) {
+                               if 
(!cachefiles_ondemand_is_reopening_read(req)) {
+                                       mask |= EPOLLIN;
+                                       break;
+                               }
+                       }
+               }
        } else {
                if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
                        mask |= EPOLLIN;
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index 66bbd4f1d22a..b4af67f1cbd6 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -344,6 +344,13 @@ cachefiles_ondemand_set_object_##_state(struct 
cachefiles_object *object) \
 CACHEFILES_OBJECT_STATE_FUNCS(open);
 CACHEFILES_OBJECT_STATE_FUNCS(close);
 CACHEFILES_OBJECT_STATE_FUNCS(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
 #define CACHEFILES_ONDEMAND_OBJINFO(object)    NULL
 
@@ -373,6 +380,11 @@ static inline int cachefiles_ondemand_init_obj_info(struct 
cachefiles_object *ob
 {
        return 0;
 }
+
+static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req 
*req)
+{
+       return false;
+}
 #endif
 
 /*
-- 
2.20.1

--
Linux-cachefs mailing list
Linux-cachefs@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-cachefs