[f2fs-dev] [PATCH v2] f2fs: compress: fix overwrite may reduce compress ratio unproperly

[f2fs-dev] [PATCH v2] f2fs: compress: fix overwrite may reduce compress ratio unproperly

[Fengnan Chang]

when overwrite only first block of cluster, since cluster is not full, it
will call f2fs_write_raw_pages when f2fs_write_multi_pages, and cause the
whole cluster become uncompressed eventhough data can be compressed.
this may will make random write bench score reduce a lot.

root# dd if=/dev/zero of=./fio-test bs=1M count=1

root# sync

root# echo 3 > /proc/sys/vm/drop_caches

root# f2fs_io get_cblocks ./fio-test

root# dd if=/dev/zero of=./fio-test bs=4K count=1 oflag=direct conv=notrunc

w/o patch:
root# f2fs_io get_cblocks ./fio-test
189

w/ patch:
root# f2fs_io get_cblocks ./fio-test
192

Signed-off-by: Fengnan Chang <changfengnan@vivo.com>
---
 fs/f2fs/compress.c | 12 ++++++++++++
 fs/f2fs/data.c     |  7 +++++++
 fs/f2fs/f2fs.h     |  1 +
 3 files changed, 20 insertions(+)

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index c1bf9ad4c220..c4f36ead6f17 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -857,6 +857,18 @@ void f2fs_end_read_compressed_page(struct page *page, bool failed,
 		f2fs_decompress_cluster(dic);
 }
 
+bool is_page_same_cluster(struct compress_ctx *cc, struct pagevec *pvec, int index)
+{
+	int idx = cluster_idx(cc, pvec->pages[index]->index);
+	int i = index + 1;
+
+	for (i = index + 1; i < index + cc->cluster_size; i++) {
+		if (cluster_idx(cc, pvec->pages[i]->index) != idx)
+			return false;
+	}
+
+	return true;
+}
 static bool is_page_in_cluster(struct compress_ctx *cc, pgoff_t index)
 {
 	if (cc->cluster_idx == NULL_CLUSTER)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index f4fd6c246c9a..33ccabbe9f92 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -3025,6 +3025,13 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 								1)) {
 						retry = 1;
 						break;
+					} else if (ret2 && nr_pages - i < cc.cluster_size) {
+						retry = 1;
+						break;
+					} else if (ret2 && nr_pages - i >= cc.cluster_size &&
+						!is_page_same_cluster(&cc, &pvec, i)) {
+						retry = 1;
+						break;
 					}
 				} else {
 					goto lock_page;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 039a229e11c9..f225ea36bb60 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4031,6 +4031,7 @@ void f2fs_end_read_compressed_page(struct page *page, bool failed,
 bool f2fs_cluster_is_empty(struct compress_ctx *cc);
 bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index);
 bool f2fs_sanity_check_cluster(struct dnode_of_data *dn);
+bool is_page_same_cluster(struct compress_ctx *cc, struct pagevec *pvec, int index);
 void f2fs_compress_ctx_add_page(struct compress_ctx *cc, struct page *page);
 int f2fs_write_multi_pages(struct compress_ctx *cc,
 						int *submitted,
-- 
2.32.0



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Re: [f2fs-dev] [PATCH v2] f2fs: compress: fix overwrite may reduce compress ratio unproperly

[Chao Yu]

On 2021/10/14 21:12, Fengnan Chang wrote:
> when overwrite only first block of cluster, since cluster is not full, it
> will call f2fs_write_raw_pages when f2fs_write_multi_pages, and cause the
> whole cluster become uncompressed eventhough data can be compressed.
> this may will make random write bench score reduce a lot.
> 
> root# dd if=/dev/zero of=./fio-test bs=1M count=1
> 
> root# sync
> 
> root# echo 3 > /proc/sys/vm/drop_caches
> 
> root# f2fs_io get_cblocks ./fio-test
> 
> root# dd if=/dev/zero of=./fio-test bs=4K count=1 oflag=direct conv=notrunc
> 
> w/o patch:
> root# f2fs_io get_cblocks ./fio-test
> 189
> 
> w/ patch:
> root# f2fs_io get_cblocks ./fio-test
> 192
> 
> Signed-off-by: Fengnan Chang <changfengnan@vivo.com>
> ---
>   fs/f2fs/compress.c | 12 ++++++++++++
>   fs/f2fs/data.c     |  7 +++++++
>   fs/f2fs/f2fs.h     |  1 +
>   3 files changed, 20 insertions(+)
> 
> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
> index c1bf9ad4c220..c4f36ead6f17 100644
> --- a/fs/f2fs/compress.c
> +++ b/fs/f2fs/compress.c
> @@ -857,6 +857,18 @@ void f2fs_end_read_compressed_page(struct page *page, bool failed,
>   		f2fs_decompress_cluster(dic);
>   }
>   
> +bool is_page_same_cluster(struct compress_ctx *cc, struct pagevec *pvec, int index)

Fengnan,

It needs add f2fs prefix for non-static symbol to avoid global namespace
pollution.

Anyway, how about this?

---
  fs/f2fs/compress.c | 19 +++++++++++++++++++
  fs/f2fs/data.c     |  7 ++++---
  fs/f2fs/f2fs.h     |  2 ++
  3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index c1bf9ad4c220..15d9b89d4df0 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -881,6 +881,25 @@ bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index)
  	return is_page_in_cluster(cc, index);
  }

+bool f2fs_all_cluster_page_loaded(struct compress_ctx *cc, struct pagevec *pvec,
+						int index, int nr_pages)
+{
+	unsigned long pgidx;
+	int i;
+
+	if (nr_pages - index < cc->cluster_size)
+		return false;
+
+	pgidx = pvec->pages[index]->index;
+
+	for (i = 1; i < cc->cluster_size; i++) {
+		if (pvec->pages[index + i]->index != pgidx + i)
+			return false;
+	}
+
+	return true;
+}
+
  static bool cluster_has_invalid_data(struct compress_ctx *cc)
  {
  	loff_t i_size = i_size_read(cc->inode);
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 14fe5c6216cc..b0665f69c093 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -3075,9 +3075,10 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
  						done = 1;
  						break;
  					} else if (ret2 &&
-						!f2fs_compress_write_end(inode,
-								fsdata, page->index,
-								1)) {
+						(!f2fs_compress_write_end(inode,
+							fsdata, page->index, 1) ||
+						!f2fs_all_cluster_page_loaded(&cc,
+							&pvec, i, nr_pages))) {
  						retry = 1;
  						break;
  					}
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 7a32c2127945..b8da34198ce0 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4047,6 +4047,8 @@ void f2fs_end_read_compressed_page(struct page *page, bool failed,
  							block_t blkaddr);
  bool f2fs_cluster_is_empty(struct compress_ctx *cc);
  bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index);
+bool f2fs_all_cluster_page_loaded(struct compress_ctx *cc, struct pagevec *pvec,
+						int index, int nr_pages);
  bool f2fs_sanity_check_cluster(struct dnode_of_data *dn);
  void f2fs_compress_ctx_add_page(struct compress_ctx *cc, struct page *page);
  int f2fs_write_multi_pages(struct compress_ctx *cc,
-- 
2.32.0




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Re: [f2fs-dev] [PATCH v2] f2fs: compress: fix overwrite may reduce compress ratio unproperly

[常凤楠]

> -----Original Message-----
> From: changfengnan@vivo.com <changfengnan@vivo.com> On Behalf Of
> Chao Yu
> Sent: Thursday, October 21, 2021 10:34 PM
> To: 常凤楠 <changfengnan@vivo.com>; jaegeuk@kernel.org
> Cc: linux-f2fs-devel@lists.sourceforge.net
> Subject: Re: [PATCH v2] f2fs: compress: fix overwrite may reduce compress
> ratio unproperly
> 
> On 2021/10/14 21:12, Fengnan Chang wrote:
> > when overwrite only first block of cluster, since cluster is not full,
> > it will call f2fs_write_raw_pages when f2fs_write_multi_pages, and
> > cause the whole cluster become uncompressed eventhough data can be
> compressed.
> > this may will make random write bench score reduce a lot.
> >
> > root# dd if=/dev/zero of=./fio-test bs=1M count=1
> >
> > root# sync
> >
> > root# echo 3 > /proc/sys/vm/drop_caches
> >
> > root# f2fs_io get_cblocks ./fio-test
> >
> > root# dd if=/dev/zero of=./fio-test bs=4K count=1 oflag=direct
> > conv=notrunc
> >
> > w/o patch:
> > root# f2fs_io get_cblocks ./fio-test
> > 189
> >
> > w/ patch:
> > root# f2fs_io get_cblocks ./fio-test
> > 192
> >
> > Signed-off-by: Fengnan Chang <changfengnan@vivo.com>
> > ---
> >   fs/f2fs/compress.c | 12 ++++++++++++
> >   fs/f2fs/data.c     |  7 +++++++
> >   fs/f2fs/f2fs.h     |  1 +
> >   3 files changed, 20 insertions(+)
> >
> > diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index
> > c1bf9ad4c220..c4f36ead6f17 100644
> > --- a/fs/f2fs/compress.c
> > +++ b/fs/f2fs/compress.c
> > @@ -857,6 +857,18 @@ void f2fs_end_read_compressed_page(struct page
> *page, bool failed,
> >   		f2fs_decompress_cluster(dic);
> >   }
> >
> > +bool is_page_same_cluster(struct compress_ctx *cc, struct pagevec
> > +*pvec, int index)
> 
> Fengnan,
> 
> It needs add f2fs prefix for non-static symbol to avoid global namespace
> pollution.
> 
> Anyway, how about this?

It looks good for me, you can make this as V3.
> 
> ---
>   fs/f2fs/compress.c | 19 +++++++++++++++++++
>   fs/f2fs/data.c     |  7 ++++---
>   fs/f2fs/f2fs.h     |  2 ++
>   3 files changed, 25 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index
> c1bf9ad4c220..15d9b89d4df0 100644
> --- a/fs/f2fs/compress.c
> +++ b/fs/f2fs/compress.c
> @@ -881,6 +881,25 @@ bool f2fs_cluster_can_merge_page(struct
> compress_ctx *cc, pgoff_t index)
>   	return is_page_in_cluster(cc, index);
>   }
> 
> +bool f2fs_all_cluster_page_loaded(struct compress_ctx *cc, struct pagevec
> *pvec,
> +						int index, int nr_pages)
> +{
> +	unsigned long pgidx;
> +	int i;
> +
> +	if (nr_pages - index < cc->cluster_size)
> +		return false;
> +
> +	pgidx = pvec->pages[index]->index;
> +
> +	for (i = 1; i < cc->cluster_size; i++) {
> +		if (pvec->pages[index + i]->index != pgidx + i)
> +			return false;
> +	}
> +
> +	return true;
> +}
> +
>   static bool cluster_has_invalid_data(struct compress_ctx *cc)
>   {
>   	loff_t i_size = i_size_read(cc->inode); diff --git a/fs/f2fs/data.c
> b/fs/f2fs/data.c index 14fe5c6216cc..b0665f69c093 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -3075,9 +3075,10 @@ static int f2fs_write_cache_pages(struct
> address_space *mapping,
>   						done = 1;
>   						break;
>   					} else if (ret2 &&
> -						!f2fs_compress_write_end(inode,
> -								fsdata, page->index,
> -								1)) {
> +						(!f2fs_compress_write_end(inode,
> +							fsdata, page->index, 1) ||
> +						!f2fs_all_cluster_page_loaded(&cc,
> +							&pvec, i, nr_pages))) {
>   						retry = 1;
>   						break;
>   					}
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 7a32c2127945..b8da34198ce0
> 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -4047,6 +4047,8 @@ void f2fs_end_read_compressed_page(struct page
> *page, bool failed,
>   							block_t blkaddr);
>   bool f2fs_cluster_is_empty(struct compress_ctx *cc);
>   bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index);
> +bool f2fs_all_cluster_page_loaded(struct compress_ctx *cc, struct pagevec
> *pvec,
> +						int index, int nr_pages);
>   bool f2fs_sanity_check_cluster(struct dnode_of_data *dn);
>   void f2fs_compress_ctx_add_page(struct compress_ctx *cc, struct page
> *page);
>   int f2fs_write_multi_pages(struct compress_ctx *cc,
> --
> 2.32.0
> 


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Re: [f2fs-dev] [PATCH v2] f2fs: compress: fix overwrite may reduce compress ratio unproperly

[Chao Yu]

On 2021/10/22 11:53, 常凤楠 wrote:
> 
> 
>> -----Original Message-----
>> From: changfengnan@vivo.com <changfengnan@vivo.com> On Behalf Of
>> Chao Yu
>> Sent: Thursday, October 21, 2021 10:34 PM
>> To: 常凤楠 <changfengnan@vivo.com>; jaegeuk@kernel.org
>> Cc: linux-f2fs-devel@lists.sourceforge.net
>> Subject: Re: [PATCH v2] f2fs: compress: fix overwrite may reduce compress
>> ratio unproperly
>>
>> On 2021/10/14 21:12, Fengnan Chang wrote:
>>> when overwrite only first block of cluster, since cluster is not full,
>>> it will call f2fs_write_raw_pages when f2fs_write_multi_pages, and
>>> cause the whole cluster become uncompressed eventhough data can be
>> compressed.
>>> this may will make random write bench score reduce a lot.
>>>
>>> root# dd if=/dev/zero of=./fio-test bs=1M count=1
>>>
>>> root# sync
>>>
>>> root# echo 3 > /proc/sys/vm/drop_caches
>>>
>>> root# f2fs_io get_cblocks ./fio-test
>>>
>>> root# dd if=/dev/zero of=./fio-test bs=4K count=1 oflag=direct
>>> conv=notrunc
>>>
>>> w/o patch:
>>> root# f2fs_io get_cblocks ./fio-test
>>> 189
>>>
>>> w/ patch:
>>> root# f2fs_io get_cblocks ./fio-test
>>> 192
>>>
>>> Signed-off-by: Fengnan Chang <changfengnan@vivo.com>
>>> ---
>>>    fs/f2fs/compress.c | 12 ++++++++++++
>>>    fs/f2fs/data.c     |  7 +++++++
>>>    fs/f2fs/f2fs.h     |  1 +
>>>    3 files changed, 20 insertions(+)
>>>
>>> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index
>>> c1bf9ad4c220..c4f36ead6f17 100644
>>> --- a/fs/f2fs/compress.c
>>> +++ b/fs/f2fs/compress.c
>>> @@ -857,6 +857,18 @@ void f2fs_end_read_compressed_page(struct page
>> *page, bool failed,
>>>    		f2fs_decompress_cluster(dic);
>>>    }
>>>
>>> +bool is_page_same_cluster(struct compress_ctx *cc, struct pagevec
>>> +*pvec, int index)
>>
>> Fengnan,
>>
>> It needs add f2fs prefix for non-static symbol to avoid global namespace
>> pollution.
>>
>> Anyway, how about this?
> 
> It looks good for me, you can make this as V3.

Well, could you please send v3 with below updates?

Thanks,

>>
>> ---
>>    fs/f2fs/compress.c | 19 +++++++++++++++++++
>>    fs/f2fs/data.c     |  7 ++++---
>>    fs/f2fs/f2fs.h     |  2 ++
>>    3 files changed, 25 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index
>> c1bf9ad4c220..15d9b89d4df0 100644
>> --- a/fs/f2fs/compress.c
>> +++ b/fs/f2fs/compress.c
>> @@ -881,6 +881,25 @@ bool f2fs_cluster_can_merge_page(struct
>> compress_ctx *cc, pgoff_t index)
>>    	return is_page_in_cluster(cc, index);
>>    }
>>
>> +bool f2fs_all_cluster_page_loaded(struct compress_ctx *cc, struct pagevec
>> *pvec,
>> +						int index, int nr_pages)
>> +{
>> +	unsigned long pgidx;
>> +	int i;
>> +
>> +	if (nr_pages - index < cc->cluster_size)
>> +		return false;
>> +
>> +	pgidx = pvec->pages[index]->index;
>> +
>> +	for (i = 1; i < cc->cluster_size; i++) {
>> +		if (pvec->pages[index + i]->index != pgidx + i)
>> +			return false;
>> +	}
>> +
>> +	return true;
>> +}
>> +
>>    static bool cluster_has_invalid_data(struct compress_ctx *cc)
>>    {
>>    	loff_t i_size = i_size_read(cc->inode); diff --git a/fs/f2fs/data.c
>> b/fs/f2fs/data.c index 14fe5c6216cc..b0665f69c093 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -3075,9 +3075,10 @@ static int f2fs_write_cache_pages(struct
>> address_space *mapping,
>>    						done = 1;
>>    						break;
>>    					} else if (ret2 &&
>> -						!f2fs_compress_write_end(inode,
>> -								fsdata, page->index,
>> -								1)) {
>> +						(!f2fs_compress_write_end(inode,
>> +							fsdata, page->index, 1) ||
>> +						!f2fs_all_cluster_page_loaded(&cc,
>> +							&pvec, i, nr_pages))) {
>>    						retry = 1;
>>    						break;
>>    					}
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 7a32c2127945..b8da34198ce0
>> 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -4047,6 +4047,8 @@ void f2fs_end_read_compressed_page(struct page
>> *page, bool failed,
>>    							block_t blkaddr);
>>    bool f2fs_cluster_is_empty(struct compress_ctx *cc);
>>    bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index);
>> +bool f2fs_all_cluster_page_loaded(struct compress_ctx *cc, struct pagevec
>> *pvec,
>> +						int index, int nr_pages);
>>    bool f2fs_sanity_check_cluster(struct dnode_of_data *dn);
>>    void f2fs_compress_ctx_add_page(struct compress_ctx *cc, struct page
>> *page);
>>    int f2fs_write_multi_pages(struct compress_ctx *cc,
>> --
>> 2.32.0
>>
> 


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