Commit c1f6925e1091("mm: put readahead pages in cache earlier") requires
fs to implement readahead callback. Otherwise there will be a
performance regression.
Commit 9eec1d897139("squashfs: provide backing_dev_info in order to
disable read-ahead") mitigates the performance drop issue for squashfs
by closing readahead for it.
This series implements readahead callback for squashfs. The previous
discussion are in [1] and [2].
[1] https://lore.kernel.org/all/CAJMQK-g9G6KQmH-V=BRGX0swZji9Wxe_2c7ht-MMAapdFy2pXw@mail.gmail.com/T/
[2] https://lore.kernel.org/linux-mm/[email protected]/t/#m4af4473b94f98a4996cb11756b633a07e5e059d1
Hsin-Yi Wang (2):
Revert "squashfs: provide backing_dev_info in order to disable
read-ahead"
squashfs: implement readahead
fs/squashfs/file.c | 77 +++++++++++++++++++++++++++++++++++++++++++++
fs/squashfs/super.c | 33 -------------------
2 files changed, 77 insertions(+), 33 deletions(-)
--
2.36.0.550.gb090851708-goog
This reverts commit 9eec1d897139e5de287af5d559a02b811b844d82.
Revert closing the readahead to squashfs since the readahead callback
for squashfs is implemented.
Suggested-by: Xiongwei Song <[email protected]>
Signed-off-by: Hsin-Yi Wang <[email protected]>
---
fs/squashfs/super.c | 33 ---------------------------------
1 file changed, 33 deletions(-)
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
index 6d594ba2ed28..32565dafa7f3 100644
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -29,7 +29,6 @@
#include <linux/module.h>
#include <linux/magic.h>
#include <linux/xattr.h>
-#include <linux/backing-dev.h>
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
@@ -113,24 +112,6 @@ static const struct squashfs_decompressor *supported_squashfs_filesystem(
return decompressor;
}
-static int squashfs_bdi_init(struct super_block *sb)
-{
- int err;
- unsigned int major = MAJOR(sb->s_dev);
- unsigned int minor = MINOR(sb->s_dev);
-
- bdi_put(sb->s_bdi);
- sb->s_bdi = &noop_backing_dev_info;
-
- err = super_setup_bdi_name(sb, "squashfs_%u_%u", major, minor);
- if (err)
- return err;
-
- sb->s_bdi->ra_pages = 0;
- sb->s_bdi->io_pages = 0;
-
- return 0;
-}
static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc)
{
@@ -146,20 +127,6 @@ static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc)
TRACE("Entered squashfs_fill_superblock\n");
- /*
- * squashfs provides 'backing_dev_info' in order to disable read-ahead. For
- * squashfs, I/O is not deferred, it is done immediately in read_folio,
- * which means the user would always have to wait their own I/O. So the effect
- * of readahead is very weak for squashfs. squashfs_bdi_init will set
- * sb->s_bdi->ra_pages and sb->s_bdi->io_pages to 0 and close readahead for
- * squashfs.
- */
- err = squashfs_bdi_init(sb);
- if (err) {
- errorf(fc, "squashfs init bdi failed");
- return err;
- }
-
sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
if (sb->s_fs_info == NULL) {
ERROR("Failed to allocate squashfs_sb_info\n");
--
2.36.0.550.gb090851708-goog
Squashfs_readahead uses the "file direct" version of the page
actor, and so build it unconditionally.
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Phillip Lougher <[email protected]>
---
fs/squashfs/Makefile | 4 ++--
fs/squashfs/page_actor.h | 41 ----------------------------------------
2 files changed, 2 insertions(+), 43 deletions(-)
diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile
index 7bd9b8b856d0..477c89a519ee 100644
--- a/fs/squashfs/Makefile
+++ b/fs/squashfs/Makefile
@@ -5,9 +5,9 @@
obj-$(CONFIG_SQUASHFS) += squashfs.o
squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
-squashfs-y += namei.o super.o symlink.o decompressor.o
+squashfs-y += namei.o super.o symlink.o decompressor.o page_actor.o
squashfs-$(CONFIG_SQUASHFS_FILE_CACHE) += file_cache.o
-squashfs-$(CONFIG_SQUASHFS_FILE_DIRECT) += file_direct.o page_actor.o
+squashfs-$(CONFIG_SQUASHFS_FILE_DIRECT) += file_direct.o
squashfs-$(CONFIG_SQUASHFS_DECOMP_SINGLE) += decompressor_single.o
squashfs-$(CONFIG_SQUASHFS_DECOMP_MULTI) += decompressor_multi.o
squashfs-$(CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU) += decompressor_multi_percpu.o
diff --git a/fs/squashfs/page_actor.h b/fs/squashfs/page_actor.h
index 2e3073ace009..26e07373af8a 100644
--- a/fs/squashfs/page_actor.h
+++ b/fs/squashfs/page_actor.h
@@ -6,46 +6,6 @@
* Phillip Lougher <[email protected]>
*/
-#ifndef CONFIG_SQUASHFS_FILE_DIRECT
-struct squashfs_page_actor {
- void **page;
- int pages;
- int length;
- int next_page;
-};
-
-static inline struct squashfs_page_actor *squashfs_page_actor_init(void **page,
- int pages, int length)
-{
- struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL);
-
- if (actor == NULL)
- return NULL;
-
- actor->length = length ? : pages * PAGE_SIZE;
- actor->page = page;
- actor->pages = pages;
- actor->next_page = 0;
- return actor;
-}
-
-static inline void *squashfs_first_page(struct squashfs_page_actor *actor)
-{
- actor->next_page = 1;
- return actor->page[0];
-}
-
-static inline void *squashfs_next_page(struct squashfs_page_actor *actor)
-{
- return actor->next_page == actor->pages ? NULL :
- actor->page[actor->next_page++];
-}
-
-static inline void squashfs_finish_page(struct squashfs_page_actor *actor)
-{
- /* empty */
-}
-#else
struct squashfs_page_actor {
union {
void **buffer;
@@ -76,4 +36,3 @@ static inline void squashfs_finish_page(struct squashfs_page_actor *actor)
actor->squashfs_finish_page(actor);
}
#endif
-#endif
--
2.34.1