Messages in this thread | | | Date | Fri, 12 Nov 2010 15:03:33 -0500 | From | David Teigland <> | Subject | Re: [PATCH] dlm: Handle application limited situations properly. |
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On Wed, Nov 10, 2010 at 09:56:39PM -0800, David Miller wrote: > > In the normal regime where an application uses non-blocking I/O > writes on a socket, they will handle -EAGAIN and use poll() to > wait for send space. > > They don't actually sleep on the socket I/O write. > > But kernel level RPC layers that do socket I/O operations directly > and key off of -EAGAIN on the write() to "try again later" don't > use poll(), they instead have their own sleeping mechanism and > rely upon ->sk_write_space() to trigger the wakeup. > > So they do effectively sleep on the write(), but this mechanism > alone does not let the socket layers know what's going on. > > Therefore they must emulate what would have happened, otherwise > TCP cannot possibly see that the connection is application window > size limited. > > Handle this, therefore, like SUNRPC by setting SOCK_NOSPACE and > bumping the ->sk_write_count as needed when we hit the send buffer > limits. > > This should make TCP send buffer size auto-tuning and the > ->sk_write_space() callback invocations actually happen.
Thanks, pushed to git://git.kernel.org/pub/scm/linux/kernel/git/teigland/dlm.git#next
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