Re: copyin+copyout in one step ?

2013-05-28 Thread Luigi Rizzo
On Tue, May 28, 2013 at 6:56 AM, Zaphod Beeblebrox wrote: > On Mon, May 27, 2013 at 7:38 PM, Luigi Rizzo wrote: > >> >> say a process P1 wants to use the kernel to copy the content of a >> buffer SRC (in its user address space) to a buffer DST (in the >> address space of another process P2), and

Re: copyin+copyout in one step ?

2013-05-28 Thread David Chisnall
On 28 May 2013, at 05:56, Zaphod Beeblebrox wrote: > Urm... Isn't the use of shared memory the more obvious way to transfer data > between processes? Am I missing some nuance? I can't speak for Luigi's use-case, but the Binder APIs in BeOS and Android call for this kind of copy. The receiving

Re: copyin+copyout in one step ?

2013-05-27 Thread Zaphod Beeblebrox
On Mon, May 27, 2013 at 7:38 PM, Luigi Rizzo wrote: > > say a process P1 wants to use the kernel to copy the content of a > buffer SRC (in its user address space) to a buffer DST (in the > address space of another process P2), and assume that P1 issues the > request to the kernel when P2 has alre

Re: copyin+copyout in one step ?

2013-05-27 Thread Konstantin Belousov
On Tue, May 28, 2013 at 01:38:01AM +0200, Luigi Rizzo wrote: > Hi, > say a process P1 wants to use the kernel to copy the content of a > buffer SRC (in its user address space) to a buffer DST (in the > address space of another process P2), and assume that P1 issues the > request to the kernel when

Re: copyin+copyout in one step ?

2013-05-27 Thread Alfred Perlstein
On 5/27/13 4:56 PM, Alfred Perlstein wrote: On 5/27/13 4:38 PM, Luigi Rizzo wrote: Hi, say a process P1 wants to use the kernel to copy the content of a buffer SRC (in its user address space) to a buffer DST (in the address space of another process P2), and assume that P1 issues the request to t

Re: copyin+copyout in one step ?

2013-05-27 Thread Alfred Perlstein
On 5/27/13 4:38 PM, Luigi Rizzo wrote: Hi, say a process P1 wants to use the kernel to copy the content of a buffer SRC (in its user address space) to a buffer DST (in the address space of another process P2), and assume that P1 issues the request to the kernel when P2 has already told the kernel

copyin+copyout in one step ?

2013-05-27 Thread Luigi Rizzo
Hi, say a process P1 wants to use the kernel to copy the content of a buffer SRC (in its user address space) to a buffer DST (in the address space of another process P2), and assume that P1 issues the request to the kernel when P2 has already told the kernel where the data should go: P1