Re: [PATCH] mm: check pfn_valid first in zero_resv_unavail

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 11/30/17 at 12:25pm, Pavel Tatashin wrote:
> Hi Dave,
> 
> Because unavailable memory can be in the middle of a section, I think
> a proper fix would be to do pfn_valid() check only at the beginning of
> section. Otherwise, we might miss zeroing  a struct page is in the
> middle of a section but pfn_valid() could potentially return false as
> that page is indeed invalid.
> 
> So, I would do something like this:
> +                       if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))
> +                               continue;
> 
> Could you please test if this fix works?

It works.

> 
> We should really look into this memory that is reserved by memblock
> but Linux is not aware of physical backing, so far I know that only
> x86 can have such scenarios, so we should really see if the problem
> can be addressed on x86 platform. It would be very nice if we could
> enforce inside memblock to reserve only memory that has real physical
> backing.

Will resend with your suggestion along with patch log changes.

> 
> Thank you,
> Pavel

Thanks
Dave

--
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>



[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]
  Powered by Linux