On Mon, 2017-12-18 at 17:24 +0000, Trond Myklebust wrote: > On Mon, 2017-12-18 at 18:00 +0100, Mike Galbraith wrote: > > On Mon, 2017-12-18 at 11:35 -0500, J. Bruce Fields wrote: > > > > > > Like I say, I don't really understand the issues here, so it's more > > > a > > > question than an objection.... (I don't know any reason a > > > cond_resched() would be bad there.) > > > > Think of it this way: what all can be queued up behind that kworker > > that is hogging CPU for huge swaths of time? It's not only userspace > > that suffers. > > > > Any cond_sched() belongs in the loop in nfs_commit_release_pages() > (where it can be mitigated) rather than in a function whose purpose is > to free memory. There is no reason to call it from the writeback or > readpages code. Just in case NFS folks are expecting a patchlet, trash otherwise. fs/nfs: Add a resched point to nfs_commit_release_pages() During heavy NFS write, kworkers can do very large amounts of work without scheduling (82ms traced). Add a resched point. Signed-off-by: Mike Galbraith <efault@xxxxxx> Suggested-by: Trond Myklebust <trondmy@xxxxxxxxxxxxxxx> --- fs/nfs/write.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -1837,6 +1837,7 @@ static void nfs_commit_release_pages(str set_bit(NFS_CONTEXT_RESEND_WRITES, &req->wb_context->flags); next: nfs_unlock_and_release_request(req); + cond_resched(); } nfss = NFS_SERVER(data->inode); if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH) -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
