staging: erofs: add erofs_allocpage

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gao Xiang 2018-07-26 20:21:59 +08:00 committed by Greg Kroah-Hartman
parent 02827e1796
commit b29e64d879
3 changed files with 39 additions and 1 deletions

View File

@ -7,7 +7,7 @@ ccflags-y += -Wall -DEROFS_VERSION=\"$(EROFS_VERSION)\"
obj-$(CONFIG_EROFS_FS) += erofs.o
# staging requirement: to be self-contained in its own directory
ccflags-y += -I$(src)/include
erofs-objs := super.o inode.o data.o namei.o dir.o
erofs-objs := super.o inode.o data.o namei.o dir.o utils.o
erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o
erofs-$(CONFIG_EROFS_FS_ZIP) += unzip_vle.o

View File

@ -369,5 +369,12 @@ static inline void erofs_vunmap(const void *mem, unsigned int count)
#endif
}
/* utils.c */
extern struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp);
#ifndef lru_to_page
#define lru_to_page(head) (list_entry((head)->prev, struct page, lru))
#endif
#endif

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@ -0,0 +1,31 @@
// SPDX-License-Identifier: GPL-2.0
/*
* linux/drivers/staging/erofs/utils.c
*
* Copyright (C) 2018 HUAWEI, Inc.
* http://www.huawei.com/
* Created by Gao Xiang <gaoxiang25@huawei.com>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of the Linux
* distribution for more details.
*/
#include "internal.h"
struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp)
{
struct page *page;
if (!list_empty(pool)) {
page = lru_to_page(pool);
list_del(&page->lru);
} else {
page = alloc_pages(gfp | __GFP_NOFAIL, 0);
BUG_ON(page == NULL);
BUG_ON(page->mapping != NULL);
}
return page;
}