On Sun, Jan 02, 2022 at 04:19:41PM +0000, Matthew Wilcox wrote:
> On Wed, Dec 08, 2021 at 04:22:08AM +0000, Matthew Wilcox (Oracle) wrote:
> > This all passes xfstests with no new failures on both xfs and tmpfs.
> > I intend to put all this into for-next tomorrow.
>
> As a result of Christoph's review, here's the diff. I don't
> think it's worth re-posting the entire patch series.
After further review and integrating Hugh's fixes, here's what
I've just updated the for-next tree with. A little late, but that's
this time of year ...
diff --git a/mm/internal.h b/mm/internal.h
index e989d8ceec91..26af8a5a5be3 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -76,28 +76,7 @@ static inline bool can_madv_lru_vma(struct vm_area_struct *vma)
return !(vma->vm_flags & (VM_LOCKED|VM_HUGETLB|VM_PFNMAP));
}
-/*
- * Parameter block passed down to zap_pte_range in exceptional cases.
- */
-struct zap_details {
- struct address_space *zap_mapping; /* Check page->mapping if set */
- struct folio *single_folio; /* Locked folio to be unmapped */
-};
-
-/*
- * We set details->zap_mappings when we want to unmap shared but keep private
- * pages. Return true if skip zapping this page, false otherwise.
- */
-static inline bool
-zap_skip_check_mapping(struct zap_details *details, struct page *page)
-{
- if (!details || !page)
- return false;
-
- return details->zap_mapping &&
- (details->zap_mapping != page_rmapping(page));
-}
-
+struct zap_details;
void unmap_page_range(struct mmu_gather *tlb,
struct vm_area_struct *vma,
unsigned long addr, unsigned long end,
diff --git a/mm/memory.c b/mm/memory.c
index a86027026f2a..23f2f1300d42 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1304,6 +1304,28 @@ copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma)
return ret;
}
+/*
+ * Parameter block passed down to zap_pte_range in exceptional cases.
+ */
+struct zap_details {
+ struct address_space *zap_mapping; /* Check page->mapping if set */
+ struct folio *single_folio; /* Locked folio to be unmapped */
+};
+
+/*
+ * We set details->zap_mapping when we want to unmap shared but keep private
+ * pages. Return true if skip zapping this page, false otherwise.
+ */
+static inline bool
+zap_skip_check_mapping(struct zap_details *details, struct page *page)
+{
+ if (!details || !page)
+ return false;
+
+ return details->zap_mapping &&
+ (details->zap_mapping != page_rmapping(page));
+}
+
static unsigned long zap_pte_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long end,
diff --git a/mm/shmem.c b/mm/shmem.c
index 637de21ff40b..28d627444a24 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -151,19 +151,6 @@ int shmem_getpage(struct inode *inode, pgoff_t index,
mapping_gfp_mask(inode->i_mapping), NULL, NULL, NULL);
}
-static int shmem_get_folio(struct inode *inode, pgoff_t index,
- struct folio **foliop, enum sgp_type sgp)
-{
- struct page *page = NULL;
- int ret = shmem_getpage(inode, index, &page, sgp);
-
- if (page)
- *foliop = page_folio(page);
- else
- *foliop = NULL;
- return ret;
-}
-
static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
{
return sb->s_fs_info;
@@ -890,6 +877,28 @@ void shmem_unlock_mapping(struct address_space *mapping)
}
}
+static struct folio *shmem_get_partial_folio(struct inode *inode, pgoff_t index)
+{
+ struct folio *folio;
+ struct page *page;
+
+ /*
+ * At first avoid shmem_getpage(,,,SGP_READ): that fails
+ * beyond i_size, and reports fallocated pages as holes.
+ */
+ folio = __filemap_get_folio(inode->i_mapping, index,
+ FGP_ENTRY | FGP_LOCK, 0);
+ if (!xa_is_value(folio))
+ return folio;
+ /*
+ * But read a page back from swap if any of it is within i_size
+ * (although in some cases this is just a waste of time).
+ */
+ page = NULL;
+ shmem_getpage(inode, index, &page, SGP_READ);
+ return page ? page_folio(page) : NULL;
+}
+
/*
* Remove range of pages and swap entries from page cache, and free them.
* If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate.
@@ -904,10 +913,10 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
struct folio_batch fbatch;
pgoff_t indices[PAGEVEC_SIZE];
struct folio *folio;
+ bool same_folio;
long nr_swaps_freed = 0;
pgoff_t index;
int i;
- bool partial_end;
if (lend == -1)
end = -1; /* unsigned, so actually very big */
@@ -943,14 +952,10 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
index++;
}
- partial_end = ((lend + 1) % PAGE_SIZE) != 0;
- shmem_get_folio(inode, lstart >> PAGE_SHIFT, &folio, SGP_READ);
+ same_folio = (lstart >> PAGE_SHIFT) == (lend >> PAGE_SHIFT);
+ folio = shmem_get_partial_folio(inode, lstart >> PAGE_SHIFT);
if (folio) {
- bool same_folio;
-
same_folio = lend < folio_pos(folio) + folio_size(folio);
- if (same_folio)
- partial_end = false;
folio_mark_dirty(folio);
if (!truncate_inode_partial_folio(folio, lstart, lend)) {
start = folio->index + folio_nr_pages(folio);
@@ -962,8 +967,8 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
folio = NULL;
}
- if (partial_end)
- shmem_get_folio(inode, end, &folio, SGP_READ);
+ if (!same_folio)
+ folio = shmem_get_partial_folio(inode, lend >> PAGE_SHIFT);
if (folio) {
folio_mark_dirty(folio);
if (!truncate_inode_partial_folio(folio, lstart, lend))
diff --git a/mm/truncate.c b/mm/truncate.c
index 749aac71fda5..5c87cdc70e7b 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -351,7 +351,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
pgoff_t index;
int i;
struct folio *folio;
- bool partial_end;
+ bool same_folio;
if (mapping_empty(mapping))
goto out;
@@ -388,12 +388,10 @@ void truncate_inode_pages_range(struct address_space *mapping,
cond_resched();
}
- partial_end = ((lend + 1) % PAGE_SIZE) != 0;
+ same_folio = (lstart >> PAGE_SHIFT) == (lend >> PAGE_SHIFT);
folio = __filemap_get_folio(mapping, lstart >> PAGE_SHIFT, FGP_LOCK, 0);
if (folio) {
- bool same_folio = lend < folio_pos(folio) + folio_size(folio);
- if (same_folio)
- partial_end = false;
+ same_folio = lend < folio_pos(folio) + folio_size(folio);
if (!truncate_inode_partial_folio(folio, lstart, lend)) {
start = folio->index + folio_nr_pages(folio);
if (same_folio)
@@ -404,8 +402,9 @@ void truncate_inode_pages_range(struct address_space *mapping,
folio = NULL;
}
- if (partial_end)
- folio = __filemap_get_folio(mapping, end, FGP_LOCK, 0);
+ if (!same_folio)
+ folio = __filemap_get_folio(mapping, lend >> PAGE_SHIFT,
+ FGP_LOCK, 0);
if (folio) {
if (!truncate_inode_partial_folio(folio, lstart, lend))
end = folio->index;
