* [PATCH] erofs-utils: use qsort() to sort dir->i_subdirs
@ 2021-04-01 13:52 Hu Weiwen
2021-04-02 2:12 ` Gao Xiang
0 siblings, 1 reply; 8+ messages in thread
From: Hu Weiwen @ 2021-04-01 13:52 UTC (permalink / raw)
To: hsiangkao, linux-erofs
Original implementation use insertion sort, and its time complexity is
O(n^2). This patch use qsort instead. When I create a directory with
100k entries, this reduces the user space time from around 3 mins to
0.5s.
Create such a large directory for benchmark with:
mkdir large; cd large; touch $(seq 100000);
Signed-off-by: Hu Weiwen <sehuww@mail.scut.edu.cn>
---
lib/inode.c | 53 +++++++++++++++++++++++++++++++++--------------------
1 file changed, 33 insertions(+), 20 deletions(-)
diff --git a/lib/inode.c b/lib/inode.c
index d52facf..9217127 100644
--- a/lib/inode.c
+++ b/lib/inode.c
@@ -96,21 +96,6 @@ unsigned int erofs_iput(struct erofs_inode *inode)
return 0;
}
-static int dentry_add_sorted(struct erofs_dentry *d, struct list_head *head)
-{
- struct list_head *pos;
-
- list_for_each(pos, head) {
- struct erofs_dentry *d2 =
- container_of(pos, struct erofs_dentry, d_child);
-
- if (strcmp(d->name, d2->name) < 0)
- break;
- }
- list_add_tail(&d->d_child, pos);
- return 0;
-}
-
struct erofs_dentry *erofs_d_alloc(struct erofs_inode *parent,
const char *name)
{
@@ -122,7 +107,7 @@ struct erofs_dentry *erofs_d_alloc(struct erofs_inode *parent,
strncpy(d->name, name, EROFS_NAME_LEN - 1);
d->name[EROFS_NAME_LEN - 1] = '\0';
- dentry_add_sorted(d, &parent->i_subdirs);
+ list_add_tail(&d->d_child, &parent->i_subdirs);
return d;
}
@@ -156,10 +141,19 @@ static int __allocate_inode_bh_data(struct erofs_inode *inode,
return 0;
}
+static int comp_subdir(const void *a, const void *b)
+{
+ const struct erofs_dentry *d_a, *d_b;
+
+ d_a = *((const struct erofs_dentry **)a);
+ d_b = *((const struct erofs_dentry **)b);
+ return strcmp(d_a->name, d_b->name);
+}
+
-int erofs_prepare_dir_file(struct erofs_inode *dir)
+int erofs_prepare_dir_file(struct erofs_inode *dir, unsigned int nr_subdirs)
{
- struct erofs_dentry *d;
- unsigned int d_size, i_nlink;
+ struct erofs_dentry *d, **all_d;
+ unsigned int d_size, i_nlink, i;
int ret;
/* dot is pointed to the current dir inode */
@@ -172,6 +166,22 @@ int erofs_prepare_dir_file(struct erofs_inode *dir)
d->inode = erofs_igrab(dir->i_parent);
d->type = EROFS_FT_DIR;
+ /* sort subdirs */
+ nr_subdirs += 2;
+ all_d = malloc(nr_subdirs * sizeof(d));
+ if (!all_d)
+ return -ENOMEM;
+ i = 0;
+ list_for_each_entry(d, &dir->i_subdirs, d_child)
+ all_d[i++] = d;
+ DBG_BUGON(i != nr_subdirs);
+ qsort(all_d, nr_subdirs, sizeof(d), comp_subdir);
+ init_list_head(&dir->i_subdirs);
+ for (i = 0; i < nr_subdirs; i++)
+ list_add_tail(&all_d[i]->d_child, &dir->i_subdirs);
+ free(all_d);
+ all_d = NULL;
+
/* let's calculate dir size and update i_nlink */
d_size = 0;
i_nlink = 0;
@@ -922,6 +932,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
DIR *_dir;
struct dirent *dp;
struct erofs_dentry *d;
+ unsigned int nr_subdirs;
ret = erofs_prepare_xattr_ibody(dir);
if (ret < 0)
@@ -961,6 +972,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
return ERR_PTR(-errno);
}
+ nr_subdirs = 0;
while (1) {
/*
* set errno to 0 before calling readdir() in order to
@@ -984,6 +996,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
ret = PTR_ERR(d);
goto err_closedir;
}
+ nr_subdirs++;
/* to count i_nlink for directories */
d->type = (dp->d_type == DT_DIR ?
@@ -996,7 +1009,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
}
closedir(_dir);
- ret = erofs_prepare_dir_file(dir);
+ ret = erofs_prepare_dir_file(dir, nr_subdirs);
if (ret)
goto err;
--
2.25.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] erofs-utils: use qsort() to sort dir->i_subdirs
2021-04-01 13:52 [PATCH] erofs-utils: use qsort() to sort dir->i_subdirs Hu Weiwen
@ 2021-04-02 2:12 ` Gao Xiang
2021-04-02 2:17 ` Gao Xiang
0 siblings, 1 reply; 8+ messages in thread
From: Gao Xiang @ 2021-04-02 2:12 UTC (permalink / raw)
To: Hu Weiwen; +Cc: linux-erofs
Hi Weiwen,
On Thu, Apr 01, 2021 at 09:52:51PM +0800, Hu Weiwen wrote:
> Original implementation use insertion sort, and its time complexity is
> O(n^2). This patch use qsort instead. When I create a directory with
> 100k entries, this reduces the user space time from around 3 mins to
> 0.5s.
>
> Create such a large directory for benchmark with:
> mkdir large; cd large; touch $(seq 100000);
>
> Signed-off-by: Hu Weiwen <sehuww@mail.scut.edu.cn>
Thanks for your work. Yeah, it's another path that needs to be
optimized for huge dirs.
The overall looks good to me, some nits below...
> ---
> lib/inode.c | 53 +++++++++++++++++++++++++++++++++--------------------
> 1 file changed, 33 insertions(+), 20 deletions(-)
>
> diff --git a/lib/inode.c b/lib/inode.c
> index d52facf..9217127 100644
> --- a/lib/inode.c
> +++ b/lib/inode.c
> @@ -96,21 +96,6 @@ unsigned int erofs_iput(struct erofs_inode *inode)
> return 0;
> }
>
> -static int dentry_add_sorted(struct erofs_dentry *d, struct list_head *head)
> -{
> - struct list_head *pos;
> -
> - list_for_each(pos, head) {
> - struct erofs_dentry *d2 =
> - container_of(pos, struct erofs_dentry, d_child);
> -
> - if (strcmp(d->name, d2->name) < 0)
> - break;
> - }
> - list_add_tail(&d->d_child, pos);
> - return 0;
> -}
> -
> struct erofs_dentry *erofs_d_alloc(struct erofs_inode *parent,
> const char *name)
> {
> @@ -122,7 +107,7 @@ struct erofs_dentry *erofs_d_alloc(struct erofs_inode *parent,
> strncpy(d->name, name, EROFS_NAME_LEN - 1);
> d->name[EROFS_NAME_LEN - 1] = '\0';
>
> - dentry_add_sorted(d, &parent->i_subdirs);
> + list_add_tail(&d->d_child, &parent->i_subdirs);
> return d;
> }
>
> @@ -156,10 +141,19 @@ static int __allocate_inode_bh_data(struct erofs_inode *inode,
> return 0;
> }
>
> +static int comp_subdir(const void *a, const void *b)
> +{
> + const struct erofs_dentry *d_a, *d_b;
> +
> + d_a = *((const struct erofs_dentry **)a);
> + d_b = *((const struct erofs_dentry **)b);
> + return strcmp(d_a->name, d_b->name);
> +}
How about just use `da' and `db' for size?
> +
> -int erofs_prepare_dir_file(struct erofs_inode *dir)
> +int erofs_prepare_dir_file(struct erofs_inode *dir, unsigned int nr_subdirs)
> {
> - struct erofs_dentry *d;
> - unsigned int d_size, i_nlink;
> + struct erofs_dentry *d, **all_d;
> + unsigned int d_size, i_nlink, i;
> int ret;
>
> /* dot is pointed to the current dir inode */
> @@ -172,6 +166,22 @@ int erofs_prepare_dir_file(struct erofs_inode *dir)
> d->inode = erofs_igrab(dir->i_parent);
> d->type = EROFS_FT_DIR;
>
> + /* sort subdirs */
> + nr_subdirs += 2;
> + all_d = malloc(nr_subdirs * sizeof(d));
maybe just use `sorted' name here?
> + if (!all_d)
> + return -ENOMEM;
> + i = 0;
> + list_for_each_entry(d, &dir->i_subdirs, d_child)
I think we could list_del here, and use list_for_each_entry
> + all_d[i++] = d;
> + DBG_BUGON(i != nr_subdirs);
> + qsort(all_d, nr_subdirs, sizeof(d), comp_subdir);
> + init_list_head(&dir->i_subdirs);
After list_del, no need to init_list_head again.
The another reason is that some list_add_tail implementation
could check elements isn't in a list first.
> + for (i = 0; i < nr_subdirs; i++)
> + list_add_tail(&all_d[i]->d_child, &dir->i_subdirs);
> + free(all_d);
> + all_d = NULL;
no need to NULLify it..
Thanks,
Gao Xiang
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] erofs-utils: use qsort() to sort dir->i_subdirs
2021-04-02 2:12 ` Gao Xiang
@ 2021-04-02 2:17 ` Gao Xiang
2021-04-05 9:38 ` [PATCH v2] " Hu Weiwen
0 siblings, 1 reply; 8+ messages in thread
From: Gao Xiang @ 2021-04-02 2:17 UTC (permalink / raw)
To: Hu Weiwen; +Cc: linux-erofs
On Fri, Apr 02, 2021 at 10:12:50AM +0800, Gao Xiang wrote:
> Hi Weiwen,
>
> On Thu, Apr 01, 2021 at 09:52:51PM +0800, Hu Weiwen wrote:
> > Original implementation use insertion sort, and its time complexity is
> > O(n^2). This patch use qsort instead. When I create a directory with
> > 100k entries, this reduces the user space time from around 3 mins to
> > 0.5s.
> >
> > Create such a large directory for benchmark with:
> > mkdir large; cd large; touch $(seq 100000);
> >
> > Signed-off-by: Hu Weiwen <sehuww@mail.scut.edu.cn>
>
> Thanks for your work. Yeah, it's another path that needs to be
> optimized for huge dirs.
>
> The overall looks good to me, some nits below...
>
> > ---
> > lib/inode.c | 53 +++++++++++++++++++++++++++++++++--------------------
> > 1 file changed, 33 insertions(+), 20 deletions(-)
> >
> > diff --git a/lib/inode.c b/lib/inode.c
> > index d52facf..9217127 100644
> > --- a/lib/inode.c
> > +++ b/lib/inode.c
> > @@ -96,21 +96,6 @@ unsigned int erofs_iput(struct erofs_inode *inode)
> > return 0;
> > }
> >
> > -static int dentry_add_sorted(struct erofs_dentry *d, struct list_head *head)
> > -{
> > - struct list_head *pos;
> > -
> > - list_for_each(pos, head) {
> > - struct erofs_dentry *d2 =
> > - container_of(pos, struct erofs_dentry, d_child);
> > -
> > - if (strcmp(d->name, d2->name) < 0)
> > - break;
> > - }
> > - list_add_tail(&d->d_child, pos);
> > - return 0;
> > -}
> > -
> > struct erofs_dentry *erofs_d_alloc(struct erofs_inode *parent,
> > const char *name)
> > {
> > @@ -122,7 +107,7 @@ struct erofs_dentry *erofs_d_alloc(struct erofs_inode *parent,
> > strncpy(d->name, name, EROFS_NAME_LEN - 1);
> > d->name[EROFS_NAME_LEN - 1] = '\0';
> >
> > - dentry_add_sorted(d, &parent->i_subdirs);
> > + list_add_tail(&d->d_child, &parent->i_subdirs);
> > return d;
> > }
> >
> > @@ -156,10 +141,19 @@ static int __allocate_inode_bh_data(struct erofs_inode *inode,
> > return 0;
> > }
> >
> > +static int comp_subdir(const void *a, const void *b)
> > +{
> > + const struct erofs_dentry *d_a, *d_b;
> > +
> > + d_a = *((const struct erofs_dentry **)a);
> > + d_b = *((const struct erofs_dentry **)b);
> > + return strcmp(d_a->name, d_b->name);
> > +}
>
> How about just use `da' and `db' for size?
... for these...
>
> > +
> > -int erofs_prepare_dir_file(struct erofs_inode *dir)
> > +int erofs_prepare_dir_file(struct erofs_inode *dir, unsigned int nr_subdirs)
> > {
> > - struct erofs_dentry *d;
> > - unsigned int d_size, i_nlink;
> > + struct erofs_dentry *d, **all_d;
> > + unsigned int d_size, i_nlink, i;
> > int ret;
> >
> > /* dot is pointed to the current dir inode */
> > @@ -172,6 +166,22 @@ int erofs_prepare_dir_file(struct erofs_inode *dir)
> > d->inode = erofs_igrab(dir->i_parent);
> > d->type = EROFS_FT_DIR;
> >
> > + /* sort subdirs */
> > + nr_subdirs += 2;
> > + all_d = malloc(nr_subdirs * sizeof(d));
>
> maybe just use `sorted' name here?
>
> > + if (!all_d)
> > + return -ENOMEM;
> > + i = 0;
> > + list_for_each_entry(d, &dir->i_subdirs, d_child)
>
> I think we could list_del here, and use list_for_each_entry
Ah, I meant list_for_each_entry_safe. The reply was somewhat
buggy as well..
>
> > + all_d[i++] = d;
> > + DBG_BUGON(i != nr_subdirs);
> > + qsort(all_d, nr_subdirs, sizeof(d), comp_subdir);
> > + init_list_head(&dir->i_subdirs);
>
> After list_del, no need to init_list_head again.
> The another reason is that some list_add_tail implementation
> could check elements isn't in a list first.
>
> > + for (i = 0; i < nr_subdirs; i++)
> > + list_add_tail(&all_d[i]->d_child, &dir->i_subdirs);
> > + free(all_d);
> > + all_d = NULL;
>
> no need to NULLify it..
>
> Thanks,
> Gao Xiang
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2] erofs-utils: use qsort() to sort dir->i_subdirs
2021-04-02 2:17 ` Gao Xiang
@ 2021-04-05 9:38 ` Hu Weiwen
2021-04-05 11:24 ` Gao Xiang
2021-04-11 14:10 ` Li GuiFu via Linux-erofs
0 siblings, 2 replies; 8+ messages in thread
From: Hu Weiwen @ 2021-04-05 9:38 UTC (permalink / raw)
To: hsiangkao, linux-erofs
Original implementation use insertion sort, and its time complexity is
O(n^2). This patch use qsort instead. When I create a directory with
100k entries, this reduces the user space time from around 3 mins to
0.5s.
Create such a large directory for benchmark with:
mkdir large; cd large; touch $(seq 100000);
Signed-off-by: Hu Weiwen <sehuww@mail.scut.edu.cn>
---
lib/inode.c | 53 +++++++++++++++++++++++++++++++++--------------------
1 file changed, 33 insertions(+), 20 deletions(-)
diff --git a/lib/inode.c b/lib/inode.c
index d52facf..ef55e88 100644
--- a/lib/inode.c
+++ b/lib/inode.c
@@ -96,21 +96,6 @@ unsigned int erofs_iput(struct erofs_inode *inode)
return 0;
}
-static int dentry_add_sorted(struct erofs_dentry *d, struct list_head *head)
-{
- struct list_head *pos;
-
- list_for_each(pos, head) {
- struct erofs_dentry *d2 =
- container_of(pos, struct erofs_dentry, d_child);
-
- if (strcmp(d->name, d2->name) < 0)
- break;
- }
- list_add_tail(&d->d_child, pos);
- return 0;
-}
-
struct erofs_dentry *erofs_d_alloc(struct erofs_inode *parent,
const char *name)
{
@@ -122,7 +107,7 @@ struct erofs_dentry *erofs_d_alloc(struct erofs_inode *parent,
strncpy(d->name, name, EROFS_NAME_LEN - 1);
d->name[EROFS_NAME_LEN - 1] = '\0';
- dentry_add_sorted(d, &parent->i_subdirs);
+ list_add_tail(&d->d_child, &parent->i_subdirs);
return d;
}
@@ -156,10 +141,19 @@ static int __allocate_inode_bh_data(struct erofs_inode *inode,
return 0;
}
+static int comp_subdir(const void *a, const void *b)
+{
+ const struct erofs_dentry *da, *db;
+
+ da = *((const struct erofs_dentry **)a);
+ db = *((const struct erofs_dentry **)b);
+ return strcmp(da->name, db->name);
+}
+
-int erofs_prepare_dir_file(struct erofs_inode *dir)
+int erofs_prepare_dir_file(struct erofs_inode *dir, unsigned int nr_subdirs)
{
- struct erofs_dentry *d;
- unsigned int d_size, i_nlink;
+ struct erofs_dentry *d, *n, **sorted_d;
+ unsigned int d_size, i_nlink, i;
int ret;
/* dot is pointed to the current dir inode */
@@ -172,6 +166,22 @@ int erofs_prepare_dir_file(struct erofs_inode *dir)
d->inode = erofs_igrab(dir->i_parent);
d->type = EROFS_FT_DIR;
+ /* sort subdirs */
+ nr_subdirs += 2;
+ sorted_d = malloc(nr_subdirs * sizeof(d));
+ if (!sorted_d)
+ return -ENOMEM;
+ i = 0;
+ list_for_each_entry_safe(d, n, &dir->i_subdirs, d_child) {
+ list_del(&d->d_child);
+ sorted_d[i++] = d;
+ }
+ DBG_BUGON(i != nr_subdirs);
+ qsort(sorted_d, nr_subdirs, sizeof(d), comp_subdir);
+ for (i = 0; i < nr_subdirs; i++)
+ list_add_tail(&sorted_d[i]->d_child, &dir->i_subdirs);
+ free(sorted_d);
+
/* let's calculate dir size and update i_nlink */
d_size = 0;
i_nlink = 0;
@@ -922,6 +932,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
DIR *_dir;
struct dirent *dp;
struct erofs_dentry *d;
+ unsigned int nr_subdirs;
ret = erofs_prepare_xattr_ibody(dir);
if (ret < 0)
@@ -961,6 +972,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
return ERR_PTR(-errno);
}
+ nr_subdirs = 0;
while (1) {
/*
* set errno to 0 before calling readdir() in order to
@@ -984,6 +996,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
ret = PTR_ERR(d);
goto err_closedir;
}
+ nr_subdirs++;
/* to count i_nlink for directories */
d->type = (dp->d_type == DT_DIR ?
@@ -996,7 +1009,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
}
closedir(_dir);
- ret = erofs_prepare_dir_file(dir);
+ ret = erofs_prepare_dir_file(dir, nr_subdirs);
if (ret)
goto err;
--
2.25.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v2] erofs-utils: use qsort() to sort dir->i_subdirs
2021-04-05 9:38 ` [PATCH v2] " Hu Weiwen
@ 2021-04-05 11:24 ` Gao Xiang
2021-04-11 14:10 ` Li GuiFu via Linux-erofs
1 sibling, 0 replies; 8+ messages in thread
From: Gao Xiang @ 2021-04-05 11:24 UTC (permalink / raw)
To: Hu Weiwen; +Cc: linux-erofs
On Mon, Apr 05, 2021 at 05:38:16PM +0800, Hu Weiwen wrote:
> Original implementation use insertion sort, and its time complexity is
> O(n^2). This patch use qsort instead. When I create a directory with
> 100k entries, this reduces the user space time from around 3 mins to
> 0.5s.
>
> Create such a large directory for benchmark with:
> mkdir large; cd large; touch $(seq 100000);
>
> Signed-off-by: Hu Weiwen <sehuww@mail.scut.edu.cn>
This patch looks good to me, will test it later.
> ---
> lib/inode.c | 53 +++++++++++++++++++++++++++++++++--------------------
> 1 file changed, 33 insertions(+), 20 deletions(-)
>
> diff --git a/lib/inode.c b/lib/inode.c
> index d52facf..ef55e88 100644
> --- a/lib/inode.c
> +++ b/lib/inode.c
> @@ -96,21 +96,6 @@ unsigned int erofs_iput(struct erofs_inode *inode)
> return 0;
> }
>
> -static int dentry_add_sorted(struct erofs_dentry *d, struct list_head *head)
> -{
> - struct list_head *pos;
> -
> - list_for_each(pos, head) {
> - struct erofs_dentry *d2 =
> - container_of(pos, struct erofs_dentry, d_child);
> -
> - if (strcmp(d->name, d2->name) < 0)
> - break;
> - }
> - list_add_tail(&d->d_child, pos);
> - return 0;
> -}
> -
> struct erofs_dentry *erofs_d_alloc(struct erofs_inode *parent,
> const char *name)
> {
> @@ -122,7 +107,7 @@ struct erofs_dentry *erofs_d_alloc(struct erofs_inode *parent,
> strncpy(d->name, name, EROFS_NAME_LEN - 1);
> d->name[EROFS_NAME_LEN - 1] = '\0';
>
> - dentry_add_sorted(d, &parent->i_subdirs);
> + list_add_tail(&d->d_child, &parent->i_subdirs);
> return d;
> }
>
> @@ -156,10 +141,19 @@ static int __allocate_inode_bh_data(struct erofs_inode *inode,
> return 0;
> }
>
> +static int comp_subdir(const void *a, const void *b)
> +{
> + const struct erofs_dentry *da, *db;
> +
> + da = *((const struct erofs_dentry **)a);
> + db = *((const struct erofs_dentry **)b);
> + return strcmp(da->name, db->name);
> +}
> +
> -int erofs_prepare_dir_file(struct erofs_inode *dir)
> +int erofs_prepare_dir_file(struct erofs_inode *dir, unsigned int nr_subdirs)
> {
> - struct erofs_dentry *d;
> - unsigned int d_size, i_nlink;
> + struct erofs_dentry *d, *n, **sorted_d;
> + unsigned int d_size, i_nlink, i;
> int ret;
>
> /* dot is pointed to the current dir inode */
> @@ -172,6 +166,22 @@ int erofs_prepare_dir_file(struct erofs_inode *dir)
> d->inode = erofs_igrab(dir->i_parent);
> d->type = EROFS_FT_DIR;
>
> + /* sort subdirs */
> + nr_subdirs += 2;
> + sorted_d = malloc(nr_subdirs * sizeof(d));
> + if (!sorted_d)
> + return -ENOMEM;
> + i = 0;
> + list_for_each_entry_safe(d, n, &dir->i_subdirs, d_child) {
> + list_del(&d->d_child);
> + sorted_d[i++] = d;
> + }
> + DBG_BUGON(i != nr_subdirs);
> + qsort(sorted_d, nr_subdirs, sizeof(d), comp_subdir);
> + for (i = 0; i < nr_subdirs; i++)
> + list_add_tail(&sorted_d[i]->d_child, &dir->i_subdirs);
> + free(sorted_d);
> +
> /* let's calculate dir size and update i_nlink */
> d_size = 0;
> i_nlink = 0;
> @@ -922,6 +932,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
> DIR *_dir;
> struct dirent *dp;
> struct erofs_dentry *d;
> + unsigned int nr_subdirs;
>
> ret = erofs_prepare_xattr_ibody(dir);
> if (ret < 0)
> @@ -961,6 +972,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
> return ERR_PTR(-errno);
> }
>
> + nr_subdirs = 0;
> while (1) {
> /*
> * set errno to 0 before calling readdir() in order to
> @@ -984,6 +996,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
> ret = PTR_ERR(d);
> goto err_closedir;
> }
> + nr_subdirs++;
>
> /* to count i_nlink for directories */
> d->type = (dp->d_type == DT_DIR ?
> @@ -996,7 +1009,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
> }
> closedir(_dir);
>
> - ret = erofs_prepare_dir_file(dir);
> + ret = erofs_prepare_dir_file(dir, nr_subdirs);
> if (ret)
> goto err;
>
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] erofs-utils: use qsort() to sort dir->i_subdirs
2021-04-05 9:38 ` [PATCH v2] " Hu Weiwen
2021-04-05 11:24 ` Gao Xiang
@ 2021-04-11 14:10 ` Li GuiFu via Linux-erofs
2021-04-11 14:41 ` Gao Xiang
1 sibling, 1 reply; 8+ messages in thread
From: Li GuiFu via Linux-erofs @ 2021-04-11 14:10 UTC (permalink / raw)
To: Hu Weiwen, hsiangkao, linux-erofs
Hu Weiwen
It really do a high sort performance increase,
I have a idea that keeping the erofs_prepare_dir_file() function
paramter stable, Using a independent function to do dirs sort.
On 2021/4/5 17:38, Hu Weiwen wrote:
> Original implementation use insertion sort, and its time complexity is
> O(n^2). This patch use qsort instead. When I create a directory with
> 100k entries, this reduces the user space time from around 3 mins to
> 0.5s.
>
> Create such a large directory for benchmark with:
> mkdir large; cd large; touch $(seq 100000);
>
> Signed-off-by: Hu Weiwen <sehuww@mail.scut.edu.cn>
> ---
> lib/inode.c | 53 +++++++++++++++++++++++++++++++++--------------------
> 1 file changed, 33 insertions(+), 20 deletions(-)
>
> diff --git a/lib/inode.c b/lib/inode.c
> index d52facf..ef55e88 100644
> --- a/lib/inode.c
> +++ b/lib/inode.c
> @@ -96,21 +96,6 @@ unsigned int erofs_iput(struct erofs_inode *inode)
> return 0;
> }
>
> -static int dentry_add_sorted(struct erofs_dentry *d, struct list_head *head)
> -{
> - struct list_head *pos;
> -
> - list_for_each(pos, head) {
> - struct erofs_dentry *d2 =
> - container_of(pos, struct erofs_dentry, d_child);
> -
> - if (strcmp(d->name, d2->name) < 0)
> - break;
> - }
> - list_add_tail(&d->d_child, pos);
> - return 0;
> -}
> -
> struct erofs_dentry *erofs_d_alloc(struct erofs_inode *parent,
> const char *name)
> {
> @@ -122,7 +107,7 @@ struct erofs_dentry *erofs_d_alloc(struct erofs_inode *parent,
> strncpy(d->name, name, EROFS_NAME_LEN - 1);
> d->name[EROFS_NAME_LEN - 1] = '\0';
>
> - dentry_add_sorted(d, &parent->i_subdirs);
> + list_add_tail(&d->d_child, &parent->i_subdirs);
> return d;
> }
>
> @@ -156,10 +141,19 @@ static int __allocate_inode_bh_data(struct erofs_inode *inode,
> return 0;
> }
>
> +static int comp_subdir(const void *a, const void *b)
> +{
> + const struct erofs_dentry *da, *db;
> +
> + da = *((const struct erofs_dentry **)a);
> + db = *((const struct erofs_dentry **)b);
> + return strcmp(da->name, db->name);
> +}
> +
> -int erofs_prepare_dir_file(struct erofs_inode *dir)
> +int erofs_prepare_dir_file(struct erofs_inode *dir, unsigned int nr_subdirs)
Todo 1: keep these function parameter stable
> {
> - struct erofs_dentry *d;
> - unsigned int d_size, i_nlink;
> + struct erofs_dentry *d, *n, **sorted_d;
> + unsigned int d_size, i_nlink, i;
> int ret;
>
> /* dot is pointed to the current dir inode */
> @@ -172,6 +166,22 @@ int erofs_prepare_dir_file(struct erofs_inode *dir)
> d->inode = erofs_igrab(dir->i_parent);
> d->type = EROFS_FT_DIR;
>
> + /* sort subdirs */
> + nr_subdirs += 2;
> + sorted_d = malloc(nr_subdirs * sizeof(d));
> + if (!sorted_d)
> + return -ENOMEM;
> + i = 0;
> + list_for_each_entry_safe(d, n, &dir->i_subdirs, d_child) {
> + list_del(&d->d_child);
> + sorted_d[i++] = d;
> + }
> + DBG_BUGON(i != nr_subdirs);
> + qsort(sorted_d, nr_subdirs, sizeof(d), comp_subdir);
> + for (i = 0; i < nr_subdirs; i++)
> + list_add_tail(&sorted_d[i]->d_child, &dir->i_subdirs);
> + free(sorted_d);
> +
Todo 2: make these codes refact to a independent function
> /* let's calculate dir size and update i_nlink */
> d_size = 0;
> i_nlink = 0;
> @@ -922,6 +932,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
> DIR *_dir;
> struct dirent *dp;
> struct erofs_dentry *d;
> + unsigned int nr_subdirs;
>
> ret = erofs_prepare_xattr_ibody(dir);
> if (ret < 0)
> @@ -961,6 +972,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
> return ERR_PTR(-errno);
> }
>
> + nr_subdirs = 0;
> while (1) {
> /*
> * set errno to 0 before calling readdir() in order to
> @@ -984,6 +996,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
> ret = PTR_ERR(d);
> goto err_closedir;
> }
> + nr_subdirs++;
>
> /* to count i_nlink for directories */
> d->type = (dp->d_type == DT_DIR ?
> @@ -996,7 +1009,7 @@ struct erofs_inode *erofs_mkfs_build_tree(struct erofs_inode *dir)
> }
> closedir(_dir);
>
> - ret = erofs_prepare_dir_file(dir);
> + ret = erofs_prepare_dir_file(dir, nr_subdirs);
Todo 3 : nr_subdirs may not be needed, it can be get from one
for-loop-count fixly.
If it may cause perfermance decrease, try to add a dir count in the
erofs_inode struct
> if (ret)
> goto err;
>
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] erofs-utils: use qsort() to sort dir->i_subdirs
2021-04-11 14:10 ` Li GuiFu via Linux-erofs
@ 2021-04-11 14:41 ` Gao Xiang
2021-04-11 14:56 ` Li GuiFu via Linux-erofs
0 siblings, 1 reply; 8+ messages in thread
From: Gao Xiang @ 2021-04-11 14:41 UTC (permalink / raw)
To: Li GuiFu; +Cc: linux-erofs
Guifu,
On Sun, Apr 11, 2021 at 10:10:09PM +0800, Li GuiFu via Linux-erofs wrote:
> Hu Weiwen
> It really do a high sort performance increase,
> I have a idea that keeping the erofs_prepare_dir_file() function
> paramter stable, Using a independent function to do dirs sort.
>
I think Weiwen's implementation looks fine to me, if you tend to
not passing nr_subdirs as a cleaner solution, my suggestion would
be:
1) introduce a somewhat erofs_subdirs, which includes
- a list_head for all subdir dentries generated from d_alloc;
- a nr_subdirs count;
2) update erofs_d_alloc to
erofs_d_alloc(struct erofs_subdirs *, const char *);
3) update erofs_prepare_dir_file to
erofs_prepare_dir_file(struct erofs_inode *, struct erofs_subdir *).
Yet I'd like to apply the current solution first since it helps the
dir creation performance. If someone has interest to the solution
above, new cleanup is always welcomed.
Reviewed-by: Gao Xiang <xiang@kernel.org>
Thanks,
Gao Xiang
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] erofs-utils: use qsort() to sort dir->i_subdirs
2021-04-11 14:41 ` Gao Xiang
@ 2021-04-11 14:56 ` Li GuiFu via Linux-erofs
0 siblings, 0 replies; 8+ messages in thread
From: Li GuiFu via Linux-erofs @ 2021-04-11 14:56 UTC (permalink / raw)
To: Gao Xiang; +Cc: linux-erofs
On 2021/4/11 22:41, Gao Xiang wrote:
> Guifu,
>
> On Sun, Apr 11, 2021 at 10:10:09PM +0800, Li GuiFu via Linux-erofs wrote:
>> Hu Weiwen
>> It really do a high sort performance increase,
>> I have a idea that keeping the erofs_prepare_dir_file() function
>> paramter stable, Using a independent function to do dirs sort.
>>
>
> I think Weiwen's implementation looks fine to me, if you tend to
> not passing nr_subdirs as a cleaner solution, my suggestion would
> be:
> 1) introduce a somewhat erofs_subdirs, which includes
> - a list_head for all subdir dentries generated from d_alloc;
> - a nr_subdirs count;
> 2) update erofs_d_alloc to
> erofs_d_alloc(struct erofs_subdirs *, const char *);
> 3) update erofs_prepare_dir_file to
> erofs_prepare_dir_file(struct erofs_inode *, struct erofs_subdir *).
>
> Yet I'd like to apply the current solution first since it helps the
> dir creation performance. If someone has interest to the solution
> above, new cleanup is always welcomed.
>
> Reviewed-by: Gao Xiang <xiang@kernel.org>
>
ok, It is also good
Reviewed-by: Li Guifu <bluce.lee@aliyun.com>
Thanks,
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2021-04-11 14:56 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-01 13:52 [PATCH] erofs-utils: use qsort() to sort dir->i_subdirs Hu Weiwen
2021-04-02 2:12 ` Gao Xiang
2021-04-02 2:17 ` Gao Xiang
2021-04-05 9:38 ` [PATCH v2] " Hu Weiwen
2021-04-05 11:24 ` Gao Xiang
2021-04-11 14:10 ` Li GuiFu via Linux-erofs
2021-04-11 14:41 ` Gao Xiang
2021-04-11 14:56 ` Li GuiFu via Linux-erofs
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