From: Renzo D. <re...@cs...> - 2009-03-16 12:18:03
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Dear Cong, Thank you for the detailed analysis of the code. I'll change the code taking care of your observations asap. On Mon, Mar 16, 2009 at 04:15:08PM +0800, Am??rico Wang wrote: > >I have updated the patch, now it should be (more) consistent > >with the Coding Style specifications. > You can use scripts/checkpatch.pl to check it before sending. I read the coding style document and I used the perl script. However, the script is not able to cope with all the style specifications and I may have missed something more. > > >UML tests at startup which features are provided and uses PTRACE_VM or > >PTRACE_SYSEMU (or nothing). PTRACE_VM and/or PTRACE_SYSEMU support can be > >disabled by command line flags. > So what? PTRACE_VM is only supported in UML with this patch, > UML still has to use PTRACE_SYSEMU on x86_32. > > Am I missing something? :) This patch [2/2] is for UML (host and guest). Patch #1 provides PTRACE_VM for all the architectures supporting ptrace via tracehook. By applying both patches PTRACE_VM is available in the following architectures: x86*, sparc*, s390, powerpc*, ia64, sh* and um. (I have not tested all these architectures, but the patch applies to the core ptrace code, shared by all of them). Ptrace_vm then provides the same speedup of PTRACE_SYSEMU extending its support: - to other architectures: ports of UML or similar code for other architectures can use it - to other applications: PTRACE_SYSEMU supports the virtualization of all the system calls while by PTRACE_VM the VM monitor can virtualize some of the system calls, depending on some condition e.g. the value of a parameter. It is possible in this way give a faster implementation to partial virtual machines like my umview. With patch #2 user-mode linux also uses ptrace_vm where available. renzo |