Any modern OS should zero allocated pages for security reasons alone. Just to avoid leaking info across processes. Of course the OS could do this zeroing when reclaiming pages, but I'd assume most would do it lazily and just zero when they needed to re-allocate.
On Fri, Apr 26, 2013 at 12:25 PM, Andreas Hansson <[email protected]>wrote: > > > > On April 26, 2013, 10:02 a.m., Nilay Vaish wrote: > > > You comment that the page fault handler will zero out the page. Is > this valid for all > > > versions of Linux and Android kernels? > > > > Andreas Hansson wrote: > > Yip > > I am actually quite keen to know of any *nix variant that does not do this > (which I assume is the cause for the zeroing in the first place). HPUX? > > > - Andreas > > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > http://reviews.gem5.org/r/1833/#review4298 > ----------------------------------------------------------- > > > On April 22, 2013, 2:48 p.m., Andreas Hansson wrote: > > > > ----------------------------------------------------------- > > This is an automatically generated e-mail. To reply, visit: > > http://reviews.gem5.org/r/1833/ > > ----------------------------------------------------------- > > > > (Updated April 22, 2013, 2:48 p.m.) > > > > > > Review request for Default. > > > > > > Description > > ------- > > > > Changeset 9672:6374801ba8f9 > > --------------------------- > > mem: Avoid explicitly zeroing the memory backing store > > > > This patch removes the explicit memset as it is redundant and causes > > the simulator to touch the entire space, forcing the host system to > > allocate the pages. > > > > Anonymous pages are mapped on the first access, and the page-fault > > handler is responsible for zeroing them. Thus, the pages are still > > zeroed, but we avoid touching the entire allocated space which enables > > us to use much larger memory sizes as long as not all the memory is > > actually used. > > > > > > Diffs > > ----- > > > > configs/common/FSConfig.py c5b24e8ed428 > > src/dev/arm/RealView.py c5b24e8ed428 > > src/mem/AbstractMemory.py c5b24e8ed428 > > src/mem/abstract_mem.hh c5b24e8ed428 > > src/mem/physical.cc c5b24e8ed428 > > > > Diff: http://reviews.gem5.org/r/1833/diff/ > > > > > > Testing > > ------- > > > > All regressions pass > > > > > > Thanks, > > > > Andreas Hansson > > > > > > _______________________________________________ > gem5-dev mailing list > [email protected] > http://m5sim.org/mailman/listinfo/gem5-dev > _______________________________________________ gem5-dev mailing list [email protected] http://m5sim.org/mailman/listinfo/gem5-dev
