* Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> wrote: > On Thu, Sep 28, 2017 at 10:07:11AM +0200, Ingo Molnar wrote: > > > > * Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> wrote: > > > > > Size of mem_section array depends on size of physical address space. > > > > > > In preparation for boot-time switching between paging modes on x86-64 > > > we need to make allocation of mem_section dynamic. > > > > > > The patch allocates the array on the first call to > > > sparse_memory_present_with_active_regions(). > > > > > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > > > > What is the size of the allocations here, in bytes, for the two main variants? > > For 4-level paging it's 32k. For 5-level paging it's 2M. Ok, please put this information into the changelog, because it's relevant: we don't want to waste 2MB of RAM on the majority of systems that boot a distro kernel with 5-level paging enabled. Thanks, Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
