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squashfs: add the mount parameter theads=<single|multi|percpu>

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Patch series 'squashfs: Add the mount parameter "threads="'.

Currently, Squashfs supports multiple decompressor parallel modes. 
However, this mode can be configured only during kernel building and does
not support flexible selection during runtime.

In the current patch set, the mount parameter "threads=" is added to allow
users to select the parallel decompressor mode and configure the number of
decompressors when mounting a file system.

"threads=<single|multi|percpu|1|2|3|...>"
The upper limit is num_online_cpus() * 2.


This patch (of 2):

Squashfs supports three decompression concurrency modes:
	Single-thread mode: concurrent reads are blocked and the memory
		overhead is small.
	Multi-thread mode/percpu mode: reduces concurrent read blocking but
		increases memory overhead.

The corresponding schema must be fixed at compile time. During mounting,
the concurrent decompression mode cannot be adjusted based on file read
blocking.

The mount parameter theads=<single|multi|percpu> is added to select
the concurrent decompression mode of a single SquashFS file system
image.

Link: https://lkml.kernel.org/r/20221019030930.130456-1-nixiaoming@huawei.com
Link: https://lkml.kernel.org/r/20221019030930.130456-2-nixiaoming@huawei.com
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Reviewed-by: Phillip Lougher <phillip@squashfs.org.uk>
Cc: Jianguo Chen <chenjianguo3@huawei.com>
Cc: Jubin Zhong <zhongjubin@huawei.com>
Cc: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Xiaoming Ni 2022-10-19 11:09:29 +08:00 committed by Andrew Morton
parent 4197530bf1
commit 80f784098f
9 changed files with 148 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
fs/squashfs/Kconfig
View File

@ -54,9 +54,36 @@ config SQUASHFS_FILE_DIRECT
endchoice
choice
prompt "Decompressor parallelisation options"
config SQUASHFS_DECOMP_SINGLE
depends on SQUASHFS
def_bool n
config SQUASHFS_DECOMP_MULTI
depends on SQUASHFS
def_bool n
config SQUASHFS_DECOMP_MULTI_PERCPU
depends on SQUASHFS
def_bool n
config SQUASHFS_CHOICE_DECOMP_BY_MOUNT
bool "Select the parallel decompression mode during mount"
depends on SQUASHFS
default n
select SQUASHFS_DECOMP_SINGLE
select SQUASHFS_DECOMP_MULTI
select SQUASHFS_DECOMP_MULTI_PERCPU
help
Compile all parallel decompression modes and specify the
decompression mode by setting "threads=" during mount.
threads=<single|multi|percpu>
default Decompressor parallelisation is SQUASHFS_DECOMP_SINGLE
choice
prompt "Select decompression parallel mode at compile time"
depends on SQUASHFS
depends on !SQUASHFS_CHOICE_DECOMP_BY_MOUNT
help
Squashfs now supports three parallelisation options for
decompression. Each one exhibits various trade-offs between
@ -64,15 +91,17 @@ choice
If in doubt, select "Single threaded compression"
config SQUASHFS_DECOMP_SINGLE
config SQUASHFS_COMPILE_DECOMP_SINGLE
bool "Single threaded compression"
select SQUASHFS_DECOMP_SINGLE
help
Traditionally Squashfs has used single-threaded decompression.
Only one block (data or metadata) can be decompressed at any
one time. This limits CPU and memory usage to a minimum.
config SQUASHFS_DECOMP_MULTI
config SQUASHFS_COMPILE_DECOMP_MULTI
bool "Use multiple decompressors for parallel I/O"
select SQUASHFS_DECOMP_MULTI
help
By default Squashfs uses a single decompressor but it gives
poor performance on parallel I/O workloads when using multiple CPU
@ -85,8 +114,9 @@ config SQUASHFS_DECOMP_MULTI
decompressors per core. It dynamically allocates decompressors
on a demand basis.
config SQUASHFS_DECOMP_MULTI_PERCPU
config SQUASHFS_COMPILE_DECOMP_MULTI_PERCPU
bool "Use percpu multiple decompressors for parallel I/O"
select SQUASHFS_DECOMP_MULTI_PERCPU
help
By default Squashfs uses a single decompressor but it gives
poor performance on parallel I/O workloads when using multiple CPU
@ -95,7 +125,6 @@ config SQUASHFS_DECOMP_MULTI_PERCPU
This decompressor implementation uses a maximum of one
decompressor per core. It uses percpu variables to ensure
decompression is load-balanced across the cores.
endchoice
config SQUASHFS_XATTR

2
fs/squashfs/block.c
View File

@ -216,7 +216,7 @@ int squashfs_read_data(struct super_block *sb, u64 index, int length,
res = -EIO;
goto out_free_bio;
}
res = squashfs_decompress(msblk, bio, offset, length, output);
res = msblk->thread_ops->decompress(msblk, bio, offset, length, output);
} else {
res = copy_bio_to_actor(bio, output, offset, length);
}

2
fs/squashfs/decompressor.c
View File

@ -134,7 +134,7 @@ void *squashfs_decompressor_setup(struct super_block *sb, unsigned short flags)
if (IS_ERR(comp_opts))
return comp_opts;
stream = squashfs_decompressor_create(msblk, comp_opts);
stream = msblk->thread_ops->create(msblk, comp_opts);
if (IS_ERR(stream))
kfree(comp_opts);

16
fs/squashfs/decompressor_multi.c
View File

@ -29,12 +29,11 @@
#define MAX_DECOMPRESSOR (num_online_cpus() * 2)
int squashfs_max_decompressors(void)
static int squashfs_max_decompressors(void)
{
return MAX_DECOMPRESSOR;
}
struct squashfs_stream {
void *comp_opts;
struct list_head strm_list;
@ -59,7 +58,7 @@ static void put_decomp_stream(struct decomp_stream *decomp_strm,
wake_up(&stream->wait);
}
void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
static void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
void *comp_opts)
{
struct squashfs_stream *stream;
@ -103,7 +102,7 @@ void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
}
void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
static void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
{
struct squashfs_stream *stream = msblk->stream;
if (stream) {
@ -180,7 +179,7 @@ static struct decomp_stream *get_decomp_stream(struct squashfs_sb_info *msblk,
}
int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
static int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
int offset, int length,
struct squashfs_page_actor *output)
{
@ -195,3 +194,10 @@ int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
msblk->decompressor->name);
return res;
}
const struct squashfs_decompressor_thread_ops squashfs_decompressor_multi = {
.create = squashfs_decompressor_create,
.destroy = squashfs_decompressor_destroy,
.decompress = squashfs_decompress,
.max_decompressors = squashfs_max_decompressors,
};

23
fs/squashfs/decompressor_multi_percpu.c
View File

@ -25,7 +25,7 @@ struct squashfs_stream {
local_lock_t lock;
};
void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
static void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
void *comp_opts)
{
struct squashfs_stream *stream;
@ -59,7 +59,7 @@ void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
return ERR_PTR(err);
}
void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
static void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
{
struct squashfs_stream __percpu *percpu =
(struct squashfs_stream __percpu *) msblk->stream;
@ -75,19 +75,21 @@ void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
}
}
int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
static int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
int offset, int length, struct squashfs_page_actor *output)
{
struct squashfs_stream *stream;
struct squashfs_stream __percpu *percpu =
(struct squashfs_stream __percpu *) msblk->stream;
int res;
local_lock(&msblk->stream->lock);
stream = this_cpu_ptr(msblk->stream);
local_lock(&percpu->lock);
stream = this_cpu_ptr(percpu);
res = msblk->decompressor->decompress(msblk, stream->stream, bio,
offset, length, output);
local_unlock(&msblk->stream->lock);
local_unlock(&percpu->lock);
if (res < 0)
ERROR("%s decompression failed, data probably corrupt\n",
@ -96,7 +98,14 @@ int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
return res;
}
int squashfs_max_decompressors(void)
static int squashfs_max_decompressors(void)
{
return num_possible_cpus();
}
const struct squashfs_decompressor_thread_ops squashfs_decompressor_percpu = {
.create = squashfs_decompressor_create,
.destroy = squashfs_decompressor_destroy,
.decompress = squashfs_decompress,
.max_decompressors = squashfs_max_decompressors,
};

15
fs/squashfs/decompressor_single.c
View File

@ -24,7 +24,7 @@ struct squashfs_stream {
struct mutex mutex;
};
void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
static void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
void *comp_opts)
{
struct squashfs_stream *stream;
@ -49,7 +49,7 @@ void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
return ERR_PTR(err);
}
void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
static void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
{
struct squashfs_stream *stream = msblk->stream;
@ -59,7 +59,7 @@ void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
}
}
int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
static int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
int offset, int length,
struct squashfs_page_actor *output)
{
@ -78,7 +78,14 @@ int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
return res;
}
int squashfs_max_decompressors(void)
static int squashfs_max_decompressors(void)
{
return 1;
}
const struct squashfs_decompressor_thread_ops squashfs_decompressor_single = {
.create = squashfs_decompressor_create,
.destroy = squashfs_decompressor_destroy,
.decompress = squashfs_decompress,
.max_decompressors = squashfs_max_decompressors,
};

23
fs/squashfs/squashfs.h
View File

@ -38,11 +38,24 @@ extern const struct squashfs_decompressor *squashfs_lookup_decompressor(int);
extern void *squashfs_decompressor_setup(struct super_block *, unsigned short);
/* decompressor_xxx.c */
extern void *squashfs_decompressor_create(struct squashfs_sb_info *, void *);
extern void squashfs_decompressor_destroy(struct squashfs_sb_info *);
extern int squashfs_decompress(struct squashfs_sb_info *, struct bio *,
int, int, struct squashfs_page_actor *);
extern int squashfs_max_decompressors(void);
struct squashfs_decompressor_thread_ops {
void * (*create)(struct squashfs_sb_info *msblk, void *comp_opts);
void (*destroy)(struct squashfs_sb_info *msblk);
int (*decompress)(struct squashfs_sb_info *msblk, struct bio *bio,
int offset, int length, struct squashfs_page_actor *output);
int (*max_decompressors)(void);
};
#ifdef CONFIG_SQUASHFS_DECOMP_SINGLE
extern const struct squashfs_decompressor_thread_ops squashfs_decompressor_single;
#endif
#ifdef CONFIG_SQUASHFS_DECOMP_MULTI
extern const struct squashfs_decompressor_thread_ops squashfs_decompressor_multi;
#endif
#ifdef CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU
extern const struct squashfs_decompressor_thread_ops squashfs_decompressor_percpu;
#endif
/* export.c */
extern __le64 *squashfs_read_inode_lookup_table(struct super_block *, u64, u64,

3
fs/squashfs/squashfs_fs_sb.h
View File

@ -53,7 +53,7 @@ struct squashfs_sb_info {
__le64 *xattr_id_table;
struct mutex meta_index_mutex;
struct meta_index *meta_index;
struct squashfs_stream *stream;
void *stream;
__le64 *inode_lookup_table;
u64 inode_table;
u64 directory_table;
@ -66,5 +66,6 @@ struct squashfs_sb_info {
int xattr_ids;
unsigned int ids;
bool panic_on_errors;
const struct squashfs_decompressor_thread_ops *thread_ops;
};
#endif

56
fs/squashfs/super.c
View File

@ -47,10 +47,12 @@ enum Opt_errors {
enum squashfs_param {
Opt_errors,
Opt_threads,
};
struct squashfs_mount_opts {
enum Opt_errors errors;
const struct squashfs_decompressor_thread_ops *thread_ops;
};
static const struct constant_table squashfs_param_errors[] = {
@ -61,9 +63,29 @@ static const struct constant_table squashfs_param_errors[] = {
static const struct fs_parameter_spec squashfs_fs_parameters[] = {
fsparam_enum("errors", Opt_errors, squashfs_param_errors),
fsparam_string("threads", Opt_threads),
{}
};
static int squashfs_parse_param_threads(const char *str, struct squashfs_mount_opts *opts)
{
#ifdef CONFIG_SQUASHFS_CHOICE_DECOMP_BY_MOUNT
if (strcmp(str, "single") == 0) {
opts->thread_ops = &squashfs_decompressor_single;
return 0;
}
if (strcmp(str, "multi") == 0) {
opts->thread_ops = &squashfs_decompressor_multi;
return 0;
}
if (strcmp(str, "percpu") == 0) {
opts->thread_ops = &squashfs_decompressor_percpu;
return 0;
}
#endif
return -EINVAL;
}
static int squashfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
struct squashfs_mount_opts *opts = fc->fs_private;
@ -78,6 +100,10 @@ static int squashfs_parse_param(struct fs_context *fc, struct fs_parameter *para
case Opt_errors:
opts->errors = result.uint_32;
break;
case Opt_threads:
if (squashfs_parse_param_threads(param->string, opts) != 0)
return -EINVAL;
break;
default:
return -EINVAL;
}
@ -167,6 +193,7 @@ static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc)
sb->s_bdev);
goto failed_mount;
}
msblk->thread_ops = opts->thread_ops;
/* Check the MAJOR & MINOR versions and lookup compression type */
msblk->decompressor = supported_squashfs_filesystem(
@ -252,7 +279,7 @@ static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc)
/* Allocate read_page block */
msblk->read_page = squashfs_cache_init("data",
squashfs_max_decompressors(), msblk->block_size);
msblk->thread_ops->max_decompressors(), msblk->block_size);
if (msblk->read_page == NULL) {
errorf(fc, "Failed to allocate read_page block");
goto failed_mount;
@ -383,7 +410,7 @@ static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc)
squashfs_cache_delete(msblk->block_cache);
squashfs_cache_delete(msblk->fragment_cache);
squashfs_cache_delete(msblk->read_page);
squashfs_decompressor_destroy(msblk);
msblk->thread_ops->destroy(msblk);
kfree(msblk->inode_lookup_table);
kfree(msblk->fragment_index);
kfree(msblk->id_table);
@ -435,6 +462,20 @@ static int squashfs_show_options(struct seq_file *s, struct dentry *root)
else
seq_puts(s, ",errors=continue");
#ifdef CONFIG_SQUASHFS_CHOICE_DECOMP_BY_MOUNT
if (msblk->thread_ops == &squashfs_decompressor_single) {
seq_puts(s, ",threads=single");
return 0;
}
if (msblk->thread_ops == &squashfs_decompressor_multi) {
seq_puts(s, ",threads=multi");
return 0;
}
if (msblk->thread_ops == &squashfs_decompressor_percpu) {
seq_puts(s, ",threads=percpu");
return 0;
}
#endif
return 0;
}
@ -446,6 +487,15 @@ static int squashfs_init_fs_context(struct fs_context *fc)
if (!opts)
return -ENOMEM;
#ifdef CONFIG_SQUASHFS_DECOMP_SINGLE
opts->thread_ops = &squashfs_decompressor_single;
#elif defined(CONFIG_SQUASHFS_DECOMP_MULTI)
opts->thread_ops = &squashfs_decompressor_multi;
#elif defined(CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU)
opts->thread_ops = &squashfs_decompressor_percpu;
#else
#error "fail: unknown squashfs decompression thread mode?"
#endif
fc->fs_private = opts;
fc->ops = &squashfs_context_ops;
return 0;
@ -478,7 +528,7 @@ static void squashfs_put_super(struct super_block *sb)
squashfs_cache_delete(sbi->block_cache);
squashfs_cache_delete(sbi->fragment_cache);
squashfs_cache_delete(sbi->read_page);
squashfs_decompressor_destroy(sbi);
sbi->thread_ops->destroy(sbi);
kfree(sbi->id_table);
kfree(sbi->fragment_index);
kfree(sbi->meta_index);