This patch adds basic functionality to put huge page into page cache.
At the moment we only put huge pages into radix-tree if the range covered
by the huge page is empty. Handling of shadow entires will be added later.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
include/linux/fs.h | 5 +++
include/linux/pagemap.h | 21 +++++++--
mm/filemap.c | 113 ++++++++++++++++++++++++++++++++++++++++++------
3 files changed, 122 insertions(+), 17 deletions(-)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b7c9198d3f54..0208b41d8de2 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1861,6 +1861,11 @@ struct super_operations {
#else
#define S_DAX 0 /* Make all the DAX code disappear */
#endif
+#define S_HUGE_MODE 0xc000
+#define S_HUGE_NEVER 0x0000
+#define S_HUGE_ALWAYS 0x4000
+#define S_HUGE_WITHIN_SIZE 0x8000
+#define S_HUGE_ADVISE 0xc000
/*
* Note that nosuid etc flags are inode-specific: setting some file-system
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 81363b834900..d9cf4e0f35dc 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -191,14 +191,20 @@ static inline int page_cache_add_speculative(struct page *page, int count)
}
#ifdef CONFIG_NUMA
-extern struct page *__page_cache_alloc(gfp_t gfp);
+extern struct page *__page_cache_alloc_order(gfp_t gfp, unsigned int order);
#else
-static inline struct page *__page_cache_alloc(gfp_t gfp)
+static inline struct page *__page_cache_alloc_order(gfp_t gfp,
+ unsigned int order)
{
- return alloc_pages(gfp, 0);
+ return alloc_pages(gfp, order);
}
#endif
+static inline struct page *__page_cache_alloc(gfp_t gfp)
+{
+ return __page_cache_alloc_order(gfp, 0);
+}
+
static inline struct page *page_cache_alloc(struct address_space *x)
{
return __page_cache_alloc(mapping_gfp_mask(x));
@@ -215,6 +221,15 @@ static inline gfp_t readahead_gfp_mask(struct address_space *x)
__GFP_COLD | __GFP_NORETRY | __GFP_NOWARN;
}
+extern bool __page_cache_allow_huge(struct address_space *x, pgoff_t offset);
+static inline bool page_cache_allow_huge(struct address_space *x,
+ pgoff_t offset)
+{
+ if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
+ return false;
+ return __page_cache_allow_huge(x, offset);
+}
+
typedef int filler_t(void *, struct page *);
pgoff_t page_cache_next_hole(struct address_space *mapping,
diff --git a/mm/filemap.c b/mm/filemap.c
index 7daedd910cf4..a3183e688718 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -636,14 +636,14 @@ static int __add_to_page_cache_locked(struct page *page,
pgoff_t offset, gfp_t gfp_mask,
void **shadowp)
{
- int huge = PageHuge(page);
+ int hugetlb = PageHuge(page);
struct mem_cgroup *memcg;
int error;
VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_PAGE(PageSwapBacked(page), page);
- if (!huge) {
+ if (!hugetlb) {
error = mem_cgroup_try_charge(page, current->mm,
gfp_mask, &memcg, false);
if (error)
@@ -652,7 +652,7 @@ static int __add_to_page_cache_locked(struct page *page,
error = radix_tree_maybe_preload(gfp_mask & ~__GFP_HIGHMEM);
if (error) {
- if (!huge)
+ if (!hugetlb)
mem_cgroup_cancel_charge(page, memcg, false);
return error;
}
@@ -662,16 +662,30 @@ static int __add_to_page_cache_locked(struct page *page,
page->index = offset;
spin_lock_irq(&mapping->tree_lock);
- error = page_cache_tree_insert(mapping, page, shadowp);
+ if (PageTransHuge(page)) {
+ /* TODO: shadow handling */
+ error = __radix_tree_insert(&mapping->page_tree, offset,
+ compound_order(page), page);
+
+ if (!error) {
+ count_vm_event(THP_FILE_ALLOC);
+ mapping->nrpages += HPAGE_PMD_NR;
+ *shadowp = NULL;
+ __inc_node_page_state(page, NR_FILE_THPS);
+ }
+ } else {
+ error = page_cache_tree_insert(mapping, page, shadowp);
+ }
radix_tree_preload_end();
if (unlikely(error))
goto err_insert;
/* hugetlb pages do not participate in page cache accounting. */
- if (!huge)
- __inc_node_page_state(page, NR_FILE_PAGES);
+ if (!hugetlb)
+ __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES,
+ hpage_nr_pages(page));
spin_unlock_irq(&mapping->tree_lock);
- if (!huge)
+ if (!hugetlb)
mem_cgroup_commit_charge(page, memcg, false, false);
trace_mm_filemap_add_to_page_cache(page);
return 0;
@@ -679,7 +693,7 @@ err_insert:
page->mapping = NULL;
/* Leave page->index set: truncation relies upon it */
spin_unlock_irq(&mapping->tree_lock);
- if (!huge)
+ if (!hugetlb)
mem_cgroup_cancel_charge(page, memcg, false);
put_page(page);
return error;
@@ -736,7 +750,7 @@ int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
EXPORT_SYMBOL_GPL(add_to_page_cache_lru);
#ifdef CONFIG_NUMA
-struct page *__page_cache_alloc(gfp_t gfp)
+struct page *__page_cache_alloc_order(gfp_t gfp, unsigned int order)
{
int n;
struct page *page;
@@ -746,14 +760,14 @@ struct page *__page_cache_alloc(gfp_t gfp)
do {
cpuset_mems_cookie = read_mems_allowed_begin();
n = cpuset_mem_spread_node();
- page = __alloc_pages_node(n, gfp, 0);
+ page = __alloc_pages_node(n, gfp, order);
} while (!page && read_mems_allowed_retry(cpuset_mems_cookie));
return page;
}
- return alloc_pages(gfp, 0);
+ return alloc_pages(gfp, order);
}
-EXPORT_SYMBOL(__page_cache_alloc);
+EXPORT_SYMBOL(__page_cache_alloc_order);
#endif
/*
@@ -1148,6 +1162,59 @@ repeat:
}
EXPORT_SYMBOL(find_lock_entry);
+bool __page_cache_allow_huge(struct address_space *mapping, pgoff_t offset)
+{
+ struct inode *inode = mapping->host;
+ void __rcu **results;
+ unsigned long idx;
+
+ offset = round_down(offset, HPAGE_PMD_NR);
+
+ switch (inode->i_flags & S_HUGE_MODE) {
+ case S_HUGE_NEVER:
+ return false;
+ case S_HUGE_ALWAYS:
+ break;
+ case S_HUGE_WITHIN_SIZE:
+ if (DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) <
+ offset + HPAGE_PMD_NR)
+ return false;
+ break;
+ case S_HUGE_ADVISE:
+ /* TODO */
+ return false;
+ default:
+ WARN_ON_ONCE(1);
+ return false;
+ }
+
+ rcu_read_lock();
+ if (radix_tree_gang_lookup_slot(&mapping->page_tree, &results, &idx,
+ offset, 1) && idx < offset + HPAGE_PMD_NR) {
+ rcu_read_unlock();
+ return false;
+ }
+ rcu_read_unlock();
+
+ return true;
+
+}
+
+static struct page *page_cache_alloc_huge(struct address_space *mapping,
+ pgoff_t offset, gfp_t gfp_mask)
+{
+ struct page *page;
+
+ if (!page_cache_allow_huge(mapping, offset))
+ return NULL;
+
+ gfp_mask |= __GFP_COMP | __GFP_NORETRY | __GFP_NOWARN;
+ page = __page_cache_alloc_order(gfp_mask, HPAGE_PMD_ORDER);
+ if (page)
+ prep_transhuge_page(page);
+ return page;
+}
+
/**
* pagecache_get_page - find and get a page reference
* @mapping: the address_space to search
@@ -2016,19 +2083,37 @@ static int page_cache_read(struct file *file, pgoff_t offset, gfp_t gfp_mask)
{
struct address_space *mapping = file->f_mapping;
struct page *page;
+ pgoff_t hoffset;
int ret;
do {
- page = __page_cache_alloc(gfp_mask|__GFP_COLD);
+ page = page_cache_alloc_huge(mapping, offset, gfp_mask);
+no_huge:
+ if (!page)
+ page = __page_cache_alloc(gfp_mask|__GFP_COLD);
if (!page)
return -ENOMEM;
- ret = add_to_page_cache_lru(page, mapping, offset, gfp_mask & GFP_KERNEL);
+ if (PageTransHuge(page))
+ hoffset = round_down(offset, HPAGE_PMD_NR);
+ else
+ hoffset = offset;
+
+ ret = add_to_page_cache_lru(page, mapping, hoffset,
+ gfp_mask & GFP_KERNEL);
if (ret == 0)
ret = mapping->a_ops->readpage(file, page);
else if (ret == -EEXIST)
ret = 0; /* losing race to add is OK */
+ if (ret && PageTransHuge(page)) {
+ delete_from_page_cache(page);
+ unlock_page(page);
+ put_page(page);
+ page = NULL;
+ goto no_huge;
+ }
+
put_page(page);
} while (ret == AOP_TRUNCATED_PAGE);
--
2.8.1
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