Messages in this thread | | | Subject | Re: [PATCH 1/3] uprobes/core: Remove redundant lock_page/unlock_page | From | Peter Zijlstra <> | Date | Thu, 31 May 2012 18:56:12 +0200 |
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On Thu, 2012-05-31 at 20:37 +0530, Srikar Dronamraju wrote: > * Peter Zijlstra <peterz@infradead.org> [2012-05-31 13:58:38]: > > > On Thu, 2012-05-31 at 17:16 +0530, Srikar Dronamraju wrote: > > > From: Srikar Dronamraju <srikar@linux.vnet.ibm.com> > > > > > > No need to lock the page when copying the opcode in read_opcode(). > > > > It would be good if the changelog said _why_ this is so :-) > > In read_opcode(), we have the reference for the page and we only are reading > from the the page. i.e we are neither modifying the page contents, not > the page attributes.
Fair enough, so put that in the changelog. The changelog should explain things, not raise questions.
> Existing kernel code has enough examples where we read the contents > of the page without taking the page lock.
Yes, but that doesn't tell us this site is ok, doing it because others do isn't an argument.
> Further this was discussed here too https://lkml.org/lkml/2012/4/17/361.
That wasn't a discussion, that was two people saying they don't know.
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