mm: swap: zswap: maybe_preload & refactoring
zswap_get_swap_cache_page and read_swap_cache_async have pretty much the
same code with only significant difference in return value and usage of
swap_readpage.
I a helper __read_swap_cache_async() with the common code. Behavior
change: now zswap_get_swap_cache_page will use radix_tree_maybe_preload
instead radix_tree_preload. Looks like, this wasn't changed only by the
reason of code duplication.
Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Seth Jennings <sjennings@variantweb.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 8bc8e66..d504adb 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -288,17 +288,14 @@
return page;
}
-/*
- * Locate a page of swap in physical memory, reserving swap cache space
- * and reading the disk if it is not already cached.
- * A failure return means that either the page allocation failed or that
- * the swap entry is no longer in use.
- */
-struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
- struct vm_area_struct *vma, unsigned long addr)
+struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
+ struct vm_area_struct *vma, unsigned long addr,
+ bool *new_page_allocated)
{
struct page *found_page, *new_page = NULL;
+ struct address_space *swapper_space = swap_address_space(entry);
int err;
+ *new_page_allocated = false;
do {
/*
@@ -306,8 +303,7 @@
* called after lookup_swap_cache() failed, re-calling
* that would confuse statistics.
*/
- found_page = find_get_page(swap_address_space(entry),
- entry.val);
+ found_page = find_get_page(swapper_space, entry.val);
if (found_page)
break;
@@ -366,7 +362,7 @@
* Initiate read into locked page and return.
*/
lru_cache_add_anon(new_page);
- swap_readpage(new_page);
+ *new_page_allocated = true;
return new_page;
}
radix_tree_preload_end();
@@ -384,6 +380,25 @@
return found_page;
}
+/*
+ * Locate a page of swap in physical memory, reserving swap cache space
+ * and reading the disk if it is not already cached.
+ * A failure return means that either the page allocation failed or that
+ * the swap entry is no longer in use.
+ */
+struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
+ struct vm_area_struct *vma, unsigned long addr)
+{
+ bool page_was_allocated;
+ struct page *retpage = __read_swap_cache_async(entry, gfp_mask,
+ vma, addr, &page_was_allocated);
+
+ if (page_was_allocated)
+ swap_readpage(retpage);
+
+ return retpage;
+}
+
static unsigned long swapin_nr_pages(unsigned long offset)
{
static unsigned long prev_offset;
