[PATCH v3 19/24] erofs: add erofs_allocpage()

Gao Xiang
2019-07-22T02:51:38Z

This patch introduces an temporary _on-stack_ page
pool to reuse the freed page directly as much as
it can for better performance and release all pages
at a time, it also slightly reduces the possibility of
the potential memory allocation failure.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
fs/erofs/internal.h | 2 ++
fs/erofs/utils.c | 14 ++++++++++++++
2 files changed, 16 insertions(+)

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index dc5c6c5e4885..506a68efe507 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -495,6 +495,8 @@ int erofs_namei(struct inode *dir, struct qstr *name,
extern const struct file_operations erofs_dir_fops;

/* utils.c */
+struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp, bool nofail);
+
#if (EROFS_PCPUBUF_NR_PAGES > 0)
void *erofs_get_pcpubuf(unsigned int pagenr);
#define erofs_put_pcpubuf(buf) do { \
diff --git a/fs/erofs/utils.c b/fs/erofs/utils.c
index c430790a02e0..53ee6daa3f70 100644
--- a/fs/erofs/utils.c
+++ b/fs/erofs/utils.c
@@ -9,6 +9,20 @@
#include "internal.h"
#include <linux/pagevec.h>

+struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp, bool nofail)
+{
+ struct page *page;
+
+ if (!list_empty(pool)) {
+ page = lru_to_page(pool);
+ DBG_BUGON(page_ref_count(page) != 1);
+ list_del(&page->lru);
+ } else {
+ page = alloc_pages(gfp | (nofail ? __GFP_NOFAIL : 0), 0);
+ }
+ return page;
+}
+
#if (EROFS_PCPUBUF_NR_PAGES > 0)
static struct {
u8 data[PAGE_SIZE * EROFS_PCPUBUF_NR_PAGES];
--
2.17.1