Re: Build error due to commit 458aa76d132dc ("mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range")

From: Guenter Roeck
Date: Tue Mar 22 2016 - 07:20:39 EST

On 03/21/2016 10:14 PM, Aneesh Kumar K.V wrote:
Guenter Roeck <linux@xxxxxxxxxxxx> writes:

[ text/plain ]

Your commit 458aa76d132dc1 ("mm/thp/migration: switch from flush_tlb_range
to flush_pmd_tlb_range") causes a build error when building

include/asm-generic/pgtable.h:799:45: note: in expansion of macro âBUILD_BUGâ
#define flush_pmd_tlb_range(vma, addr, end) BUILD_BUG()
./arch/arc/include/asm/tlbflush.h:37:13: note:
in expansion of macro âflush_pmd_tlb_rangeâ

The build triggers the newly introduced BUILD_BUG().

When building the image without the BUILD_BUG(), ie with no definition
of flush_pmd_tlb_range(), the problem is gone. This suggests that the
function is not needed for this build.

I could submit a patch to remove the BUILD_BUG(), but maybe you had a reason
for introducing it. Can you elaborate why you introduced the BUILD_BUG() ?

Isn't this going to be fixed by an update to ARC tree ?

That wasn't a build error ?

I also don't understand why we would hit that BUILD_BUG, if we are not
calling flush_pmd_tlb_range().

Good question.

I'll wait for the commit window to close and report again if needed.