lkml.org 
[lkml]   [2013]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH linux-next v2] SUNRPC: rpcrdma_register_default_external: Dynamically allocate ib_phys_buf
On Mon, Mar 11, 2013 at 12:51:44PM -0600, Tim Gardner wrote:
> On 03/11/2013 12:14 PM, J. Bruce Fields wrote:
> <snip>
> >>
> >> v2 - Move the array of 'struct ib_phys_buf' objects into struct rpcrdma_req
> >> and pass this request down through rpcrdma_register_external() and
> >> rpcrdma_register_default_external(). This is less overhead then using
> >> kmalloc() and requires no extra error checking as the allocation burden is
> >> shifted to the transport client.
> >
> > Oh good--so that works, and the req is the right place to put this? How
> > are you testing this?
> >
> > (Just want to make it clear: I'm *not* an expert on the rdma code, so my
> > suggestion to put this in the rpcrdma_req was a suggestion for something
> > to look into, not a claim that it's correct.)
> >
>
> Just compile tested so far. Incidentally, I've been through the call stack:
>
> call_transmit
> xprt_transmit
> xprt->ops->send_request(task)
> xprt_rdma_send_request
> rpcrdma_marshal_req
> rpcrdma_create_chunks
> rpcrdma_register_external
> rpcrdma_register_default_external
>
> It appears that the context for kmalloc() should be fine unless there is
> a spinlock held around call_transmit() (which seems unlikely).

Right, though I think it shouldn't be GFP_KERNEL--looks like writes
could wait on it.

In any case, the embedding-in-rpcrdma_req solution does look cleaner if
that's correct (e.g. if we can be sure there won't be two simultaneous
users of that array).

--b.


\
 
 \ /
  Last update: 2013-03-11 21:04    [W:0.130 / U:0.032 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site