On Thu, Jun 10, 2021 at 10:13 AM Trond Myklebust <trondmy@xxxxxxxxxxxxxxx> wrote: > > On Thu, 2021-06-10 at 13:56 +0000, Chuck Lever III wrote: > > > > > > > On Jun 10, 2021, at 9:34 AM, Trond Myklebust < > > > trondmy@xxxxxxxxxxxxxxx> wrote: > > > > > > On Thu, 2021-06-10 at 13:30 +0000, Chuck Lever III wrote: > > > > > > > > > > > > > On Jun 9, 2021, at 5:53 PM, Olga Kornievskaia < > > > > > olga.kornievskaia@xxxxxxxxx> wrote: > > > > > > > > > > From: Olga Kornievskaia <kolga@xxxxxxxxxx> > > > > > > > > > > This option will control up to how many xprts can the client > > > > > establish to the server. This patch parses the value and sets > > > > > up structures that keep track of max_connect. > > > > > > > > > > Signed-off-by: Olga Kornievskaia <kolga@xxxxxxxxxx> > > > > > --- > > > > > fs/nfs/client.c | 1 + > > > > > fs/nfs/fs_context.c | 8 ++++++++ > > > > > fs/nfs/internal.h | 2 ++ > > > > > fs/nfs/nfs4client.c | 12 ++++++++++-- > > > > > fs/nfs/super.c | 2 ++ > > > > > include/linux/nfs_fs_sb.h | 1 + > > > > > 6 files changed, 24 insertions(+), 2 deletions(-) > > > > > > > > > > diff --git a/fs/nfs/client.c b/fs/nfs/client.c > > > > > index 330f65727c45..486dec59972b 100644 > > > > > --- a/fs/nfs/client.c > > > > > +++ b/fs/nfs/client.c > > > > > @@ -179,6 +179,7 @@ struct nfs_client *nfs_alloc_client(const > > > > > struct nfs_client_initdata *cl_init) > > > > > > > > > > clp->cl_proto = cl_init->proto; > > > > > clp->cl_nconnect = cl_init->nconnect; > > > > > + clp->cl_max_connect = cl_init->max_connect ? cl_init- > > > > > > max_connect : 1; > > > > > > > > So, 1 is the default setting, meaning the "add another transport" > > > > facility is disabled by default. Would it be less surprising for > > > > an admin to allow some extra connections by default? > > > > > > > > > > > > > clp->cl_net = get_net(cl_init->net); > > > > > > > > > > clp->cl_principal = "*"; > > > > > diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c > > > > > index d95c9a39bc70..cfbff7098f8e 100644 > > > > > --- a/fs/nfs/fs_context.c > > > > > +++ b/fs/nfs/fs_context.c > > > > > @@ -29,6 +29,7 @@ > > > > > #endif > > > > > > > > > > #define NFS_MAX_CONNECTIONS 16 > > > > > +#define NFS_MAX_TRANSPORTS 128 > > > > > > > > This maximum seems excessive... again, there are diminishing > > > > returns to adding more connections to the same server. what's > > > > wrong with re-using NFS_MAX_CONNECTIONS for the maximum? > > > > > > > > As always, I'm a little queasy about adding yet another mount > > > > option. Are there real use cases where a whole-client setting > > > > (like a sysfs attribute) would be inadequate? Is there a way > > > > the client could figure out a reasonable maximum without a > > > > human intervention, say, by counting the number of NICs on > > > > the system? > > > > > > Oh, hell no! We're not tying anything to the number of NICs... > > > > That's a bit of an over-reaction. :-) A little more explanation > > would be welcome. I mean, don't you expect someone to ask "How > > do I pick a good value?" and someone might reasonably answer > > "Well, start with the number of NICs on your client times 3" or > > something like that. > > > > IMO we're about to add another admin setting without understanding > > how it will be used, how to select a good maximum value, or even > > whether this maximum needs to be adjustable. In a previous e-mail > > Olga has already demonstrated that it will be difficult to explain > > how to use this setting with nconnect=. > > > > Thus I would favor a (moderate) soldered-in maximum to start with, > > and then as real world use cases arise, consider adding a tuning > > mechanism based on actual requirements. > > It's not an overreaction. It's insane to think that counting NICs gives > you any notion whatsoever about the network topology and connectivity > between the client and server. It doesn't even tell you how many of > those NICs might potentially be available to your application. > > We're not doing any automation based on that kind of layering > violation. I'm not suggesting to programmatically determine the number of NIC to determine the value of max_connect. > > -- > Trond Myklebust > Linux NFS client maintainer, Hammerspace > trond.myklebust@xxxxxxxxxxxxxxx > >
