Messages in this thread | | | Date | Fri, 22 Feb 2013 02:42:52 +0400 | From | Cyrill Gorcunov <> | Subject | Re: prctl(PR_SET_MM) |
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On Thu, Feb 21, 2013 at 02:18:41PM -0800, Andrew Morton wrote: > On Thu, 21 Feb 2013 12:00:28 +0400 > Cyrill Gorcunov <gorcunov@openvz.org> wrote: > > > From: Amnon Shiloh <u3557@miso.sublimeip.com> > > Subject: prctl: Make PR_SET_MM being depend on own CONFIG_MM_FIELDS_SETTING > > > > ... > > > > Signed-off-by: Amnon Shiloh <u3557@miso.sublimeip.com> > > The "..." makes me sad. > > If/when this patch gets sent for real, please explain the reasons? > AFAICT it permits the enabling of prctl(PR_SET_MM) in > CONFIG_CHECKPOINT_RESTORE=n kernels. If that was indeed the intent, > why?
Sorry for this "...", it was a draft version for Amnon, not for inclusion. As far as I understand Amnon needs these prctl opcodes to be enabled by default (but still turnable off in Kconfig if needed) for his minimal c/r software, he do not need the whole c/r functionality (procfs map-files, get-tid-address,kcmp and such). That is the idea if I understand correctly.
Quoting Amnon | | Correct, this is an important feature that is useful for a whole | general class of applications, not only those needing CHECKPOINT_RESTORE. | | Had this not been done as part of the CHECKPOINT_RESTORE project, it | would have certainly been done, sooner or later, by some other developers: | it just so happened that the CHECKPOINT_RESTORE people were the first to | (publically) fill this gap, but in fact this code in "kernel/sys.c" should | be general kernel code, not part of CHECKPOINT_RESTORE. |
I personally don't mind if this code become y by default (it requires cap-sys-resource capability granted anyway), but for normal c/r this prctl opcodes only is not enough and CHECKPOINT_RESTORE should be set. Thus, if people agree with enabling prctl extension by default I certainly won't object.
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