Messages in this thread | | | Date | Fri, 6 Oct 2017 14:25:18 +0200 | From | Michal Hocko <> | Subject | Re: [PATCH v10 09/10] mm: stop zeroing memory during allocation in vmemmap |
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On Fri 06-10-17 12:11:42, David Laight wrote: > From: Michal Hocko > > Sent: 06 October 2017 12:47 > > On Fri 06-10-17 11:10:14, David Laight wrote: > > > From: Pavel Tatashin > > > > Sent: 05 October 2017 22:11 > > > > vmemmap_alloc_block() will no longer zero the block, so zero memory > > > > at its call sites for everything except struct pages. Struct page memory > > > > is zero'd by struct page initialization. > > > > > > It seems dangerous to change an allocator to stop zeroing memory. > > > It is probably saver to add a new function that doesn't zero > > > the memory and use that is the places where you don't want it > > > to be zeroed. > > > > Not sure what you mean. memblock_virt_alloc_try_nid_raw is a new > > function which doesn't zero out... > > You should probably leave vmemap_alloc_block() zeroing the memory > so that existing alls don't have to be changed - apart from the > ones you are explicitly optimising.
But the whole point of vmemmap_alloc_block is to allocate memmaps and the point of this change is to cover those. This is not a generic API that other users would depend on. -- Michal Hocko SUSE Labs
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