2020-09-16 16:55:46

by Chao Yu

[permalink] [raw]
Subject: [PATCH] erofs: remove unneeded parameter

From: Chao Yu <[email protected]>

In below call path, no page will be cached into @pagepool list
or grabbed from @pagepool list:
- z_erofs_readpage
- z_erofs_do_read_page
- preload_compressed_pages
- erofs_allocpage

Let's get rid of this unneeded parameter.

Signed-off-by: Chao Yu <[email protected]>
---
fs/erofs/utils.c | 2 +-
fs/erofs/zdata.c | 14 ++++++--------
2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/fs/erofs/utils.c b/fs/erofs/utils.c
index de9986d2f82f..7a6e5456b0b8 100644
--- a/fs/erofs/utils.c
+++ b/fs/erofs/utils.c
@@ -11,7 +11,7 @@ struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp)
{
struct page *page;

- if (!list_empty(pool)) {
+ if (pool && !list_empty(pool)) {
page = lru_to_page(pool);
DBG_BUGON(page_ref_count(page) != 1);
list_del(&page->lru);
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 6c939def00f9..f218f58f4159 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -153,8 +153,7 @@ static DEFINE_MUTEX(z_pagemap_global_lock);

static void preload_compressed_pages(struct z_erofs_collector *clt,
struct address_space *mc,
- enum z_erofs_cache_alloctype type,
- struct list_head *pagepool)
+ enum z_erofs_cache_alloctype type)
{
const struct z_erofs_pcluster *pcl = clt->pcl;
const unsigned int clusterpages = BIT(pcl->clusterbits);
@@ -562,8 +561,7 @@ static bool should_alloc_managed_pages(struct z_erofs_decompress_frontend *fe,
}

static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
- struct page *page,
- struct list_head *pagepool)
+ struct page *page)
{
struct inode *const inode = fe->inode;
struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
@@ -621,7 +619,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
cache_strategy = DONTALLOC;

preload_compressed_pages(clt, MNGD_MAPPING(sbi),
- cache_strategy, pagepool);
+ cache_strategy);

hitted:
/*
@@ -653,7 +651,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
/* should allocate an additional staging page for pagevec */
if (err == -EAGAIN) {
struct page *const newpage =
- erofs_allocpage(pagepool, GFP_NOFS | __GFP_NOFAIL);
+ erofs_allocpage(NULL, GFP_NOFS | __GFP_NOFAIL);

newpage->mapping = Z_EROFS_MAPPING_STAGING;
err = z_erofs_attach_page(clt, newpage,
@@ -1282,7 +1280,7 @@ static int z_erofs_readpage(struct file *file, struct page *page)

f.headoffset = (erofs_off_t)page->index << PAGE_SHIFT;

- err = z_erofs_do_read_page(&f, page, &pagepool);
+ err = z_erofs_do_read_page(&f, page);
(void)z_erofs_collector_end(&f.clt);

/* if some compressed cluster ready, need submit them anyway */
@@ -1341,7 +1339,7 @@ static void z_erofs_readahead(struct readahead_control *rac)
/* traversal in reverse order */
head = (void *)page_private(page);

- err = z_erofs_do_read_page(&f, page, &pagepool);
+ err = z_erofs_do_read_page(&f, page);
if (err)
erofs_err(inode->i_sb,
"readahead error at page %lu @ nid %llu",
--
2.22.0


2020-09-16 20:59:16

by Gao Xiang

[permalink] [raw]
Subject: Re: [PATCH] erofs: remove unneeded parameter

Hi Chao,

On Wed, Sep 16, 2020 at 10:06:04PM +0800, Chao Yu wrote:
> From: Chao Yu <[email protected]>
>
> In below call path, no page will be cached into @pagepool list
> or grabbed from @pagepool list:
> - z_erofs_readpage
> - z_erofs_do_read_page
> - preload_compressed_pages
> - erofs_allocpage
>
> Let's get rid of this unneeded parameter.

That would be unneeded after .readahead() is introduced recently
(so add_to_page_cache_lru() is also moved to mm code), so I agree
with you on it.

>
> Signed-off-by: Chao Yu <[email protected]>
> ---
> fs/erofs/utils.c | 2 +-
> fs/erofs/zdata.c | 14 ++++++--------
> 2 files changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/fs/erofs/utils.c b/fs/erofs/utils.c
> index de9986d2f82f..7a6e5456b0b8 100644
> --- a/fs/erofs/utils.c
> +++ b/fs/erofs/utils.c
> @@ -11,7 +11,7 @@ struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp)
> {
> struct page *page;
>
> - if (!list_empty(pool)) {
> + if (pool && !list_empty(pool)) {
> page = lru_to_page(pool);
> DBG_BUGON(page_ref_count(page) != 1);
> list_del(&page->lru);
> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
> index 6c939def00f9..f218f58f4159 100644
> --- a/fs/erofs/zdata.c
> +++ b/fs/erofs/zdata.c
> @@ -153,8 +153,7 @@ static DEFINE_MUTEX(z_pagemap_global_lock);
>
> static void preload_compressed_pages(struct z_erofs_collector *clt,
> struct address_space *mc,
> - enum z_erofs_cache_alloctype type,
> - struct list_head *pagepool)
> + enum z_erofs_cache_alloctype type)
> {
> const struct z_erofs_pcluster *pcl = clt->pcl;
> const unsigned int clusterpages = BIT(pcl->clusterbits);
> @@ -562,8 +561,7 @@ static bool should_alloc_managed_pages(struct z_erofs_decompress_frontend *fe,
> }
>
> static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
> - struct page *page,
> - struct list_head *pagepool)
> + struct page *page)
> {
> struct inode *const inode = fe->inode;
> struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
> @@ -621,7 +619,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
> cache_strategy = DONTALLOC;
>
> preload_compressed_pages(clt, MNGD_MAPPING(sbi),
> - cache_strategy, pagepool);
> + cache_strategy);
>
> hitted:
> /*
> @@ -653,7 +651,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
> /* should allocate an additional staging page for pagevec */
> if (err == -EAGAIN) {
> struct page *const newpage =
> - erofs_allocpage(pagepool, GFP_NOFS | __GFP_NOFAIL);
> + erofs_allocpage(NULL, GFP_NOFS | __GFP_NOFAIL);

Could we use allocpage instead, so erofs_allocpage modification is unneeded as well :)

Thanks,
Gao Xiang

2020-09-16 20:59:33

by Gao Xiang

[permalink] [raw]
Subject: Re: [PATCH] erofs: remove unneeded parameter

On Wed, Sep 16, 2020 at 10:33:04PM +0800, Gao Xiang wrote:
> Hi Chao,
>
> On Wed, Sep 16, 2020 at 10:06:04PM +0800, Chao Yu wrote:
> > From: Chao Yu <[email protected]>
> >
> > In below call path, no page will be cached into @pagepool list
> > or grabbed from @pagepool list:
> > - z_erofs_readpage
> > - z_erofs_do_read_page
> > - preload_compressed_pages
> > - erofs_allocpage
> >
> > Let's get rid of this unneeded parameter.
>
> That would be unneeded after .readahead() is introduced recently
> (so add_to_page_cache_lru() is also moved to mm code), so I agree
> with you on it.

(cont.)

... also it'd be better to add such historical reason to the commit
message... since it was of some use before...

Thanks,
Gao Xiang

2020-09-17 01:23:14

by Chao Yu

[permalink] [raw]
Subject: Re: [PATCH] erofs: remove unneeded parameter

Hi Xiang,

On 2020/9/16 22:36, Gao Xiang wrote:
> On Wed, Sep 16, 2020 at 10:33:04PM +0800, Gao Xiang wrote:
>> Hi Chao,
>>
>> On Wed, Sep 16, 2020 at 10:06:04PM +0800, Chao Yu wrote:
>>> From: Chao Yu <[email protected]>
>>>
>>> In below call path, no page will be cached into @pagepool list
>>> or grabbed from @pagepool list:
>>> - z_erofs_readpage
>>> - z_erofs_do_read_page
>>> - preload_compressed_pages
>>> - erofs_allocpage
>>>
>>> Let's get rid of this unneeded parameter.
>>
>> That would be unneeded after .readahead() is introduced recently
>> (so add_to_page_cache_lru() is also moved to mm code), so I agree
>> with you on it.
>
> (cont.)
>
> ... also it'd be better to add such historical reason to the commit
> message... since it was of some use before...

No problem, let me revise it in v2. :)

Thanks,

>
> Thanks,
> Gao Xiang
>
> .
>