Hi all,
On Mon, 2 May 2022 12:19:36 +0100 Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
>
> On Mon, May 02, 2022 at 08:49:03PM +1000, Stephen Rothwell wrote:
> >
> > After merging the mm tree, today's linux-next build (arm
> > multi_v7_defconfig) failed like this:
> [... i wish our BUILD_BUGs produced nicer output from the compiler ...]
> > Reverting the following commits makes the problem go away:
> >
> > 2b58b3f33ba2 ("mm/shmem: convert shmem_swapin_page() to shmem_swapin_folio()")
> > 94cdf3e8c0bf ("mm/shmem: convert shmem_getpage_gfp to use a folio")
> > 3674fd6cadf5 ("mm/shmem: convert shmem_alloc_and_acct_page to use a folio")
> > b0bb08b2d5f3 ("mm/shmem: turn shmem_alloc_page() into shmem_alloc_folio()")
> > 8d657a77c6fe ("mm/shmem: turn shmem_should_replace_page into shmem_should_replace_folio")
> > 9a44f3462edc ("mm/shmem: convert shmem_add_to_page_cache to take a folio")
> > 561fd8bee1dc ("mm/swap: add folio_throttle_swaprate")
> > cb4e56ee240d ("mm/shmem: use a folio in shmem_unused_huge_shrink")
> > 22bf1b68e572 ("vmscan: remove remaining uses of page in shrink_page_list")
> > 7d15d41b7c4a ("vmscan: convert the activate_locked portion of shrink_page_list to folios")
> > 8a6aff9c51c7 ("vmscan: move initialisation of mapping down")
> > b79338b3d217 ("vmscan: convert lazy freeing to folios")
> > 719426e40146 ("vmscan: convert page buffer handling to use folios")
> > 339ba7502e13 ("vmscan: convert dirty page handling to folios")
>
> Oops. allnoconfig on x86 reproduces the problem. This fixes it;
> happy to go back and produce a new set of patches for Andrew to
> preserve bisectability.
>
> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> index 2999190adc22..e9e0d591061d 100644
> --- a/include/linux/huge_mm.h
> +++ b/include/linux/huge_mm.h
> @@ -347,7 +347,6 @@ static inline void prep_transhuge_page(struct page *page) {}
> static inline bool
> can_split_folio(struct folio *folio, int *pextra_pins)
> {
> - BUILD_BUG();
> return false;
> }
> static inline int
> diff --git a/mm/shmem.c b/mm/shmem.c
> index 673a0e783496..d62936ffe74d 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -738,7 +738,7 @@ static int shmem_add_to_page_cache(struct folio *folio,
> xas_store(&xas, folio);
> if (xas_error(&xas))
> goto unlock;
> - if (folio_test_large(folio)) {
> + if (folio_test_pmd_mappable(folio)) {
> count_vm_event(THP_FILE_ALLOC);
> __lruvec_stat_mod_folio(folio, NR_SHMEM_THPS, nr);
> }
> @@ -1887,10 +1887,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
> goto unlock;
> }
>
> - if (folio_test_large(folio))
> - hindex = round_down(index, HPAGE_PMD_NR);
> - else
> - hindex = index;
> + hindex = round_down(index, folio_nr_pages(folio));
>
> if (sgp == SGP_WRITE)
> __folio_set_referenced(folio);
> @@ -1909,7 +1906,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
> spin_unlock_irq(&info->lock);
> alloced = true;
>
> - if (folio_test_large(folio) &&
> + if (folio_test_pmd_mappable(folio) &&
> DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) <
> hindex + HPAGE_PMD_NR - 1) {
> /*
>
I applied the above patch to the mm tree merge today (instead of all
the reverts) and it fixed the build problems for me.
--
Cheers,
Stephen Rothwell
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