On Wed, Feb 28, 2018 at 10:12:55AM +0300, Pavel Emelyanov wrote: > On 02/27/2018 05:18 AM, Dmitry V. Levin wrote: > > On Mon, Feb 26, 2018 at 12:02:25PM +0300, Pavel Emelyanov wrote: > >> On 02/21/2018 03:44 AM, Andrew Morton wrote: > >>> On Tue, 9 Jan 2018 08:30:49 +0200 Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> wrote: > >>> > >>>> This patches introduces new process_vmsplice system call that combines > >>>> functionality of process_vm_read and vmsplice. > >>> > >>> All seems fairly strightforward. The big question is: do we know that > >>> people will actually use this, and get sufficient value from it to > >>> justify its addition? > >> > >> Yes, that's what bothers us a lot too :) I've tried to start with finding out if anyone > >> used the sys_read/write_process_vm() calls, but failed :( Does anybody know how popular > >> these syscalls are? > > > > Well, process_vm_readv itself is quite popular, it's used by debuggers nowadays, > > see e.g. > > $ strace -qq -esignal=none -eprocess_vm_readv strace -qq -o/dev/null cat /dev/null > > I see. Well, yes, this use-case will not benefit much from remote splice. How about more > interactive debug by, say, gdb? It may attach, then splice all the memory, then analyze > the victim code/data w/o copying it to its address space? Hmm, in this case, you probably will want to be able to map pipe pages into memory. > > -- Pavel
