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Message-Id: <20211206143552.8384-1-huangjianan@oppo.com>
Date: Mon, 6 Dec 2021 22:35:52 +0800
From: Huang Jianan <jnhuang95@...il.com>
To: linux-erofs@...ts.ozlabs.org, xiang@...nel.org
Cc: chao@...nel.org, linux-kernel@...r.kernel.org, guoweichao@...o.com,
guanyuwei@...o.com, yh@...o.com, zhangshiming@...o.com,
Huang Jianan <huangjianan@...o.com>
Subject: [PATCH v7 3/3] erofs: add sysfs node to control sync decompression strategy
Although readpage is a synchronous path, there will be no additional
kworker scheduling overhead in non-atomic contexts together with
dm-verity.
Let's add a sysfs node to disable sync decompression as an option.
Signed-off-by: Huang Jianan <huangjianan@...o.com>
Reviewed-by: Chao Yu <chao@...nel.org>
---
since v6:
- Clean up code.
since v4:
- Resend in a clean chain.
since v3:
- Clean up the sync decompressstrategy into a separate function.
since v2:
- Use enum to indicate sync decompression strategy.
- Add missing CONFIG_EROFS_FS_ZIP ifdef.
since v1:
- Leave auto default.
- Add a disable strategy for sync_decompress.
Documentation/ABI/testing/sysfs-fs-erofs | 9 ++++++++
fs/erofs/internal.h | 10 +++++++--
fs/erofs/super.c | 2 +-
fs/erofs/sysfs.c | 15 ++++++++++++++
fs/erofs/zdata.c | 26 ++++++++++++++++++++----
5 files changed, 55 insertions(+), 7 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-fs-erofs b/Documentation/ABI/testing/sysfs-fs-erofs
index a9512594dc4c..05482374a741 100644
--- a/Documentation/ABI/testing/sysfs-fs-erofs
+++ b/Documentation/ABI/testing/sysfs-fs-erofs
@@ -5,3 +5,12 @@ Description: Shows all enabled kernel features.
Supported features:
zero_padding, compr_cfgs, big_pcluster, chunked_file,
device_table, compr_head2, sb_chksum.
+
+What: /sys/fs/erofs/<disk>/sync_decompress
+Date: November 2021
+Contact: "Huang Jianan" <huangjianan@...o.com>
+Description: Control strategy of sync decompression
+ - 0 (default, auto): enable for readpage, and enable for
+ readahead on atomic contexts only,
+ - 1 (force on): enable for readpage and readahead.
+ - 2 (force off): disable for all situations.
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 43f0332fa489..8e70435629e5 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -56,12 +56,18 @@ struct erofs_device_info {
u32 mapped_blkaddr;
};
+enum {
+ EROFS_SYNC_DECOMPRESS_AUTO,
+ EROFS_SYNC_DECOMPRESS_FORCE_ON,
+ EROFS_SYNC_DECOMPRESS_FORCE_OFF
+};
+
struct erofs_mount_opts {
#ifdef CONFIG_EROFS_FS_ZIP
/* current strategy of how to use managed cache */
unsigned char cache_strategy;
- /* strategy of sync decompression (false - auto, true - force on) */
- bool readahead_sync_decompress;
+ /* strategy of sync decompression (0 - auto, 1 - force on, 2 - force off) */
+ unsigned int sync_decompress;
/* threshold for decompression synchronously */
unsigned int max_sync_decompress_pages;
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index abc1da5d1719..58f381f80205 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -423,7 +423,7 @@ static void erofs_default_options(struct erofs_fs_context *ctx)
#ifdef CONFIG_EROFS_FS_ZIP
ctx->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
ctx->opt.max_sync_decompress_pages = 3;
- ctx->opt.readahead_sync_decompress = false;
+ ctx->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;
#endif
#ifdef CONFIG_EROFS_FS_XATTR
set_opt(&ctx->opt, XATTR_USER);
diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c
index ca18c5dce493..5d999015eead 100644
--- a/fs/erofs/sysfs.c
+++ b/fs/erofs/sysfs.c
@@ -16,6 +16,7 @@ enum {
enum {
struct_erofs_sb_info,
+ struct_erofs_mount_opts,
};
struct erofs_attr {
@@ -55,7 +56,14 @@ static struct erofs_attr erofs_attr_##_name = { \
#define ATTR_LIST(name) (&erofs_attr_##name.attr)
+#ifdef CONFIG_EROFS_FS_ZIP
+EROFS_ATTR_RW_UI(sync_decompress, erofs_mount_opts);
+#endif
+
static struct attribute *erofs_attrs[] = {
+#ifdef CONFIG_EROFS_FS_ZIP
+ ATTR_LIST(sync_decompress),
+#endif
NULL,
};
ATTRIBUTE_GROUPS(erofs);
@@ -86,6 +94,8 @@ static unsigned char *__struct_ptr(struct erofs_sb_info *sbi,
{
if (struct_type == struct_erofs_sb_info)
return (unsigned char *)sbi + offset;
+ if (struct_type == struct_erofs_mount_opts)
+ return (unsigned char *)&sbi->opt + offset;
return NULL;
}
@@ -132,6 +142,11 @@ static ssize_t erofs_attr_store(struct kobject *kobj, struct attribute *attr,
return ret;
if (t > UINT_MAX)
return -EINVAL;
+#ifdef CONFIG_EROFS_FS_ZIP
+ if (!strcmp(a->attr.name, "sync_decompress") &&
+ (t > EROFS_SYNC_DECOMPRESS_FORCE_OFF))
+ return -EINVAL;
+#endif
*(unsigned int *)ptr = t;
return len;
case attr_pointer_bool:
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 9a249bfc2770..bc765d8a6dc2 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -762,6 +762,21 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
goto out;
}
+static bool z_erofs_get_sync_decompress_policy(struct erofs_sb_info *sbi,
+ unsigned int readahead_pages)
+{
+ /* auto: enable for readpage, disable for readahead */
+ if ((sbi->opt.sync_decompress == EROFS_SYNC_DECOMPRESS_AUTO) &&
+ !readahead_pages)
+ return true;
+
+ if ((sbi->opt.sync_decompress == EROFS_SYNC_DECOMPRESS_FORCE_ON) &&
+ (readahead_pages <= sbi->opt.max_sync_decompress_pages))
+ return true;
+
+ return false;
+}
+
static void z_erofs_decompressqueue_work(struct work_struct *work);
static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io,
bool sync, int bios)
@@ -784,7 +799,9 @@ static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io,
/* Use workqueue and sync decompression for atomic contexts only */
if (in_atomic() || irqs_disabled()) {
queue_work(z_erofs_workqueue, &io->u.work);
- sbi->opt.readahead_sync_decompress = true;
+ /* enable sync decompression for readahead */
+ if (sbi->opt.sync_decompress == EROFS_SYNC_DECOMPRESS_AUTO)
+ sbi->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_FORCE_ON;
return;
}
z_erofs_decompressqueue_work(&io->u.work);
@@ -1435,6 +1452,7 @@ static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f,
static int z_erofs_readpage(struct file *file, struct page *page)
{
struct inode *const inode = page->mapping->host;
+ struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
struct page *pagepool = NULL;
int err;
@@ -1450,7 +1468,8 @@ static int z_erofs_readpage(struct file *file, struct page *page)
(void)z_erofs_collector_end(&f.clt);
/* if some compressed cluster ready, need submit them anyway */
- z_erofs_runqueue(inode->i_sb, &f, &pagepool, true);
+ z_erofs_runqueue(inode->i_sb, &f, &pagepool,
+ z_erofs_get_sync_decompress_policy(sbi, 0));
if (err)
erofs_err(inode->i_sb, "failed to read, err [%d]", err);
@@ -1501,8 +1520,7 @@ static void z_erofs_readahead(struct readahead_control *rac)
(void)z_erofs_collector_end(&f.clt);
z_erofs_runqueue(inode->i_sb, &f, &pagepool,
- sbi->opt.readahead_sync_decompress &&
- nr_pages <= sbi->opt.max_sync_decompress_pages);
+ z_erofs_get_sync_decompress_policy(sbi, nr_pages));
if (f.map.mpage)
put_page(f.map.mpage);
erofs_release_pages(&pagepool);
--
2.25.1
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