From b382685c1fcbaa3e5e11160f0096f9e24c7c5571 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 30 Apr 2018 14:31:30 +1000 Subject: [PATCH] NFS: use cond_resched() when restarting walk of delegation list. In three places we walk the list of delegations for an nfs_client until an interesting one is found, then we act of that delegation and restart the walk. New delegations are added to the end of a list and the interesting delegations are usually old, so in many case we won't repeat a long walk over and over again, but it is possible - particularly if the first server in the list has a large number of uninteresting delegations. In each cache the work done on interesting delegations will often complete without sleeping, so this could loop many times without giving up the CPU. So add a cond_resched() at an appropriate point to avoid hogging the CPU for too long. Signed-off-by: NeilBrown Signed-off-by: Trond Myklebust --- fs/nfs/delegation.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c index b9cd3864335b2..c454532b6f03f 100644 --- a/fs/nfs/delegation.c +++ b/fs/nfs/delegation.c @@ -508,6 +508,7 @@ restart: err = nfs_end_delegation_return(inode, delegation, 0); iput(inode); nfs_sb_deactive(server->super); + cond_resched(); if (!err) goto restart; set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state); @@ -904,6 +905,7 @@ restart: } iput(inode); nfs_sb_deactive(server->super); + cond_resched(); goto restart; } } @@ -1020,6 +1022,7 @@ restart: } iput(inode); nfs_sb_deactive(server->super); + cond_resched(); goto restart; } } -- 2.39.5