Bug 1693575

Summary: gfapi: do not block epoll thread for upcall notifications
Product: [Community] GlusterFS Reporter: Soumya Koduri <skoduri>
Component: libgfapiAssignee: Soumya Koduri <skoduri>
Status: CLOSED NEXTRELEASE QA Contact: bugs <bugs>
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Version: mainlineCC: bugs, pasik
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: 1694561 1694562 1694563 1694565 (view as bug list) Environment:
Last Closed: 2019-03-29 07:25:10 UTC Type: Bug
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Bug Blocks: 1694561, 1694562, 1694563, 1694565    

Description Soumya Koduri 2019-03-28 08:49:01 UTC 
Description of problem:

With https://review.gluster.org/#/c/glusterfs/+/21783/, we have made changes to offload processing upcall notifications to synctask so as not to block epoll threads. However seems like the purpose wasnt fully resolved. 

In "glfs_cbk_upcall_data" -> "synctask_new1" after creating synctask if there is no callback defined, the thread waits on synctask_join till the syncfn is finished. So that way even with those changes, epoll threads are blocked till the upcalls are processed.

Hence the right fix now is to define a callback function for that synctask "glfs_cbk_upcall_syncop" so as to unblock epoll/notify threads completely and the upcall processing can happen in parallel by synctask threads.

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Comment 1 Soumya Koduri 2019-03-28 09:28:58 UTC 
Users have complained about nfs-ganesha process getting stuck here - https://github.com/nfs-ganesha/nfs-ganesha/issues/335
Comment 2 Worker Ant 2019-03-28 09:34:11 UTC 
REVIEW: https://review.gluster.org/22436 (gfapi: Unblock epoll thread for upcall processing) posted (#1) for review on master by soumya k
Comment 3 Worker Ant 2019-03-29 07:25:10 UTC 
REVIEW: https://review.gluster.org/22436 (gfapi: Unblock epoll thread for upcall processing) merged (#4) on master by Amar Tumballi