On 10.04.24 18:51, Peter Xu wrote:
On Wed, Apr 10, 2024 at 06:40:55PM +0200, David Hildenbrand wrote:
On 10.04.24 18:33, Peter Xu wrote:
On Wed, Apr 10, 2024 at 06:12:34PM +0200, David Hildenbrand wrote:
On 10.04.24 18:07, Sumanth Korikkar wrote:
On Wed, Apr 10, 2024 at 05:51:28PM +0200, David Hildenbrand wrote:
On 10.04.24 17:26, Sumanth Korikkar wrote:
On Wed, Apr 10, 2024 at 02:34:35PM +0200, David Hildenbrand wrote:
On 09.04.24 17:54, Sumanth Korikkar wrote:
In order to minimize code size (CONFIG_CC_OPTIMIZE_FOR_SIZE=y),
compiler might choose to make a regular function call (out-of-line) for
shmem_is_huge() instead of inlining it. When transparent hugepages are
disabled (CONFIG_TRANSPARENT_HUGEPAGE=n), it can cause compilation
error.
mm/shmem.c: In function ‘shmem_getattr’:
./include/linux/huge_mm.h:383:27: note: in expansion of macro ‘BUILD_BUG’
383 | #define HPAGE_PMD_SIZE ({ BUILD_BUG(); 0; })
| ^~~~~~~~~
mm/shmem.c:1148:33: note: in expansion of macro ‘HPAGE_PMD_SIZE’
1148 | stat->blksize = HPAGE_PMD_SIZE;
To prevent the possible error, always inline shmem_is_huge() when
transparent hugepages are disabled.
Do you know which commit introduced that?
Hi David,
Currently with CONFIG_CC_OPTIMIZE_FOR_SIZE=y and expirementing with
-fPIC kernel compiler option, I could see this error on s390.
Got it. I assume on Linus' tree, not mm/unstable?
It's not yet upstream.
However, default kernel compiler options doesnt end up with the above
pattern right now.
Okay, just asking if this is related to recent HPAGE_PMD_SIZE changes:
commit c1a1e497a3d5711dbf8fa6d7432d6b83ec18c26f
Author: Peter Xu <peterx@xxxxxxxxxx>
Date: Wed Mar 27 11:23:22 2024 -0400
mm: make HPAGE_PXD_* macros even if !THP
Which is still in mm-unstable and not upstream.
Not related to this commit. I tried on master branch.
Thanks! Can you try with Peters patch? (ccing Peter)
If I am not wrong, that should also resolve the issue you are seeing.
David,
Do you mean this one?
https://lore.kernel.org/all/20240403013249.1418299-4-peterx@xxxxxxxxxx/
No, I meant:
https://lore.kernel.org/all/20240327152332.950956-4-peterx@xxxxxxxxxx/
which removes the "#define HPAGE_PMD_SIZE ({ BUILD_BUG(); 0; })" that we
seem to trigger here.
... but it's been a long day, so maybe I'm all wrong :)
Ah.. So I thought it was one step further. :)
Then that shouldn't be the case; it didn't remove it but defined properly
with HPAGE_PMD_SHIFT:
+#define HPAGE_PMD_SIZE ((1UL) << HPAGE_PMD_SHIFT)
Now we even have that properly defined for HUGETLB_PAGE, while prior to
that we should hit this issue easier (even with !THP+HUGETLB_PAGE).
Ah, now I spot
#define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
:) sorry for the noise!
To the original patch here
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
--
Cheers,
David / dhildenb
