[PATCH v3 2/2] erofs: add sysfs node to control sync decompression strategy
Huang Jianan
jnhuang95 at gmail.com
Wed Nov 10 02:38:56 AEDT 2021
Although readpage is a synchronous path, there will be no additional
kworker scheduling overhead in non-atomic contexts. So add a sysfs
node to allow disable sync decompression.
Signed-off-by: Huang Jianan <huangjianan at oppo.com>
---
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 | 16 ++++++++++++----
5 files changed, 45 insertions(+), 7 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-fs-erofs b/Documentation/ABI/testing/sysfs-fs-erofs
index 86d0d0234473..d301704de79b 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:
lz4_0padding, compr_cfgs, big_pcluster, device_table,
sb_chksum.
+
+What: /sys/fs/erofs/<disk>/sync_decompress
+Date: November 2021
+Contact: "Huang Jianan" <huangjianan at oppo.com>
+Description: Control strategy of sync decompression
+ - 0 (defalut, 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 d0cd712dc222..cd30d4f0bada 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 cf88e083eea5..821a73857d82 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);
@@ -82,6 +90,8 @@ 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;
}
@@ -128,6 +138,11 @@ 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 bcb1b91b234f..4c0a9fdd09ff 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -794,7 +794,7 @@ 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;
+ sbi->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_FORCE_ON;
return;
}
z_erofs_decompressqueue_work(&io->u.work);
@@ -1454,9 +1454,11 @@ 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;
+ bool force_fg = true;
trace_erofs_readpage(page, false);
f.headoffset = (erofs_off_t)page->index << PAGE_SHIFT;
@@ -1468,8 +1470,11 @@ static int z_erofs_readpage(struct file *file, struct page *page)
(void)z_erofs_collector_end(&f.clt);
+ if (sbi->opt.sync_decompress == EROFS_SYNC_DECOMPRESS_FORCE_OFF)
+ force_fg = false;
+
/* 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, force_fg);
if (err)
erofs_err(inode->i_sb, "failed to read, err [%d]", err);
@@ -1488,6 +1493,7 @@ static void z_erofs_readahead(struct readahead_control *rac)
struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
struct page *pagepool = NULL, *head = NULL, *page;
unsigned int nr_pages;
+ bool force_fg = false;
f.readahead = true;
f.headoffset = readahead_pos(rac);
@@ -1519,8 +1525,10 @@ static void z_erofs_readahead(struct readahead_control *rac)
z_erofs_pcluster_readmore(&f, rac, 0, &pagepool, false);
(void)z_erofs_collector_end(&f.clt);
- z_erofs_runqueue(inode->i_sb, &f, &pagepool,
- sbi->opt.readahead_sync_decompress &&
+ if (sbi->opt.sync_decompress == EROFS_SYNC_DECOMPRESS_FORCE_ON)
+ force_fg = true;
+
+ z_erofs_runqueue(inode->i_sb, &f, &pagepool, force_fg &&
nr_pages <= sbi->opt.max_sync_decompress_pages);
if (f.map.mpage)
put_page(f.map.mpage);
--
2.25.1
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