From: NeilBrown Date: Mon, 30 Apr 2018 04:31:30 +0000 (+1000) Subject: NFS: use cond_resched() when restarting walk of delegation list. X-Git-Tag: v4.19~741^2~63 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3ca951b618386321d9396e9e26be7f4235b5cdb2;p=platform%2Fkernel%2Flinux-rpi.git 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 --- diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c index b9cd3864..c454532 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; } }