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Message-Id: <20211109074536.23137-2-huangjianan@oppo.com>
Date: Tue, 9 Nov 2021 15:45:36 +0800
From: Huang Jianan <huangjianan@...o.com>
To: linux-erofs@...ts.ozlabs.org
Cc: huangjianan@...o.com, guoweichao@...o.com, guanyuwei@...o.com,
yh@...o.com, zhangshiming@...o.com, linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/2] 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. So add a sysfs
node to allow disable sync decompression.
Signed-off-by: Huang Jianan <huangjianan@...o.com>
---
changes since v1:
- leave auto default
- add a disable strategy for sync_decompress
Documentation/ABI/testing/sysfs-fs-erofs | 9 +++++++++
fs/erofs/internal.h | 4 ++--
fs/erofs/super.c | 2 +-
fs/erofs/sysfs.c | 10 ++++++++++
fs/erofs/zdata.c | 19 ++++++++++++++-----
5 files changed, 36 insertions(+), 8 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-fs-erofs b/Documentation/ABI/testing/sysfs-fs-erofs
index 86d0d0234473..c84f12004f02 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@...o.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 (disable): disable for all situations.
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index d0cd712dc222..06a8bbdb378f 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -60,8 +60,8 @@ 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 - disable) */
+ 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..ea223d6c7985 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 = 0;
#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 dd328d20c451..a8889b2b65f3 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 +56,10 @@ static struct erofs_attr erofs_attr_##_name = { \
#define ATTR_LIST(name) (&erofs_attr_##name.attr)
+EROFS_ATTR_RW_UI(sync_decompress, erofs_mount_opts);
+
static struct attribute *erofs_attrs[] = {
+ ATTR_LIST(sync_decompress),
NULL,
};
ATTRIBUTE_GROUPS(erofs);
@@ -82,6 +86,8 @@ 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;
}
@@ -126,6 +132,10 @@ static ssize_t erofs_attr_store(struct kobject *kobj, struct attribute *attr,
ret = kstrtoul(skip_spaces(buf), 0, &t);
if (ret)
return ret;
+
+ if (!strcmp(a->attr.name, "sync_decompress") && (t > 2))
+ return -EINVAL;
+
*((unsigned int *) ptr) = t;
return len;
case attr_pointer_bool:
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index bcb1b91b234f..70ec51fa7131 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -794,7 +794,8 @@ 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;
+ if (sbi->opt.sync_decompress == 0)
+ sbi->opt.sync_decompress = 1;
return;
}
z_erofs_decompressqueue_work(&io->u.work);
@@ -1454,9 +1455,11 @@ 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 +1471,11 @@ static int z_erofs_readpage(struct file *file, struct page *page)
(void)z_erofs_collector_end(&f.clt);
+ if (sbi->opt.sync_decompress == 2)
+ 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 +1494,7 @@ 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);
@@ -1519,9 +1526,11 @@ 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 &&
- nr_pages <= sbi->opt.max_sync_decompress_pages);
+ if (sbi->opt.sync_decompress == 1)
+ 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);
erofs_release_pages(&pagepool);
--
2.25.1
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