Messages in this thread | | | Date | Wed, 10 Apr 2024 17:26:39 +0200 | From | Sumanth Korikkar <> | Subject | Re: [PATCH] mm/shmem: Inline shmem_is_huge() for disabled transparent hugepages |
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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.
However, default kernel compiler options doesnt end up with the above pattern right now.
I think, shmem_is_huge() for disabled transparent hugepages comes from: Commit 5e6e5a12a44c ("huge tmpfs: shmem_is_huge(vma, inode, index)")
However, HPAGE_PMD_SIZE macros for !CONFIG_TRANSPARENT_HUGEPAGE originates from: Commit d8c37c480678 ("thp: add HPAGE_PMD_* definitions for !CONFIG_TRANSPARENT_HUGEPAGE")
Thanks, Sumanth
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