* [PATCH V2 1/2] f2fs: add a new function to support for merging contiguous read
@ 2013-11-16 6:14 Chao Yu
2013-11-18 0:29 ` [f2fs-dev] " Jaegeuk Kim
0 siblings, 1 reply; 6+ messages in thread
From: Chao Yu @ 2013-11-16 6:14 UTC (permalink / raw)
To: '???'; +Cc: linux-fsdevel, linux-kernel, linux-f2fs-devel
For better read performance, we add a new function to support for merging contiguous read as the one for write.
v1-->v2:
o add declarations here as Gu Zheng suggested.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Acked-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
---
fs/f2fs/data.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
fs/f2fs/f2fs.h | 4 ++++
2 files changed, 49 insertions(+)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index aa3438c..18107cb 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -404,6 +404,51 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
return 0;
}
+void f2fs_submit_read_bio(struct f2fs_sb_info *sbi, int rw)
+{
+ down_read(&sbi->bio_sem);
+ if (sbi->read_bio) {
+ submit_bio(rw, sbi->read_bio);
+ sbi->read_bio = NULL;
+ }
+ up_read(&sbi->bio_sem);
+}
+
+void submit_read_page(struct f2fs_sb_info *sbi, struct page *page,
+ block_t blk_addr, int rw)
+{
+ struct block_device *bdev = sbi->sb->s_bdev;
+ int bio_blocks;
+
+ verify_block_addr(sbi, blk_addr);
+
+ down_read(&sbi->bio_sem);
+
+ if (sbi->read_bio && sbi->last_read_block != blk_addr - 1) {
+ submit_bio(rw, sbi->read_bio);
+ sbi->read_bio = NULL;
+ }
+
+alloc_new:
+ if (sbi->read_bio == NULL) {
+ bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
+ sbi->read_bio = f2fs_bio_alloc(bdev, bio_blocks);
+ sbi->read_bio->bi_sector = SECTOR_FROM_BLOCK(sbi, blk_addr);
+ sbi->read_bio->bi_end_io = read_end_io;
+ }
+
+ if (bio_add_page(sbi->read_bio, page, PAGE_CACHE_SIZE, 0) <
+ PAGE_CACHE_SIZE) {
+ submit_bio(rw, sbi->read_bio);
+ sbi->read_bio = NULL;
+ goto alloc_new;
+ }
+
+ sbi->last_read_block = blk_addr;
+
+ up_read(&sbi->bio_sem);
+}
+
/*
* This function should be used by the data read flow only where it
* does not check the "create" flag that indicates block allocation.
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 89dc750..bfe9d87 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -359,6 +359,8 @@ struct f2fs_sb_info {
/* for segment-related operations */
struct f2fs_sm_info *sm_info; /* segment manager */
+ struct bio *read_bio; /* read bios to merge */
+ sector_t last_read_block; /* last read block number */
struct bio *bio[NR_PAGE_TYPE]; /* bios to merge */
sector_t last_block_in_bio[NR_PAGE_TYPE]; /* last block number */
struct rw_semaphore bio_sem; /* IO semaphore */
@@ -1111,6 +1113,8 @@ struct page *find_data_page(struct inode *, pgoff_t, bool);
struct page *get_lock_data_page(struct inode *, pgoff_t);
struct page *get_new_data_page(struct inode *, struct page *, pgoff_t, bool);
int f2fs_readpage(struct f2fs_sb_info *, struct page *, block_t, int);
+void f2fs_submit_read_bio(struct f2fs_sb_info *, int);
+void submit_read_page(struct f2fs_sb_info *, struct page *, block_t, int);
int do_write_data_page(struct page *);
/*
--
1.7.9.5
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^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [f2fs-dev] [PATCH V2 1/2] f2fs: add a new function to support for merging contiguous read
2013-11-16 6:14 [PATCH V2 1/2] f2fs: add a new function to support for merging contiguous read Chao Yu
@ 2013-11-18 0:29 ` Jaegeuk Kim
2013-11-18 1:37 ` Chao Yu
0 siblings, 1 reply; 6+ messages in thread
From: Jaegeuk Kim @ 2013-11-18 0:29 UTC (permalink / raw)
To: Chao Yu; +Cc: linux-fsdevel, linux-kernel, linux-f2fs-devel, 谭姝
Hi Chao,
2013-11-16 (토), 14:14 +0800, Chao Yu:
> For better read performance, we add a new function to support for merging contiguous read as the one for write.
Please consider 80 columns for the description.
I cannot fix this at every time though. :(
>
> v1-->v2:
> o add declarations here as Gu Zheng suggested.
>
> Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> Acked-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> ---
> fs/f2fs/data.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
> fs/f2fs/f2fs.h | 4 ++++
> 2 files changed, 49 insertions(+)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index aa3438c..18107cb 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -404,6 +404,51 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
> return 0;
> }
>
> +void f2fs_submit_read_bio(struct f2fs_sb_info *sbi, int rw)
> +{
> + down_read(&sbi->bio_sem);
Is there any reason to use down_read()?
It seems that we need to declare sbi->bio_read and sbi->bio_write
instead of sbi->bio_sem.
In addition to that, we need to use down_write(&sbi->bio_read) here.
> + if (sbi->read_bio) {
> + submit_bio(rw, sbi->read_bio);
> + sbi->read_bio = NULL;
> + }
> + up_read(&sbi->bio_sem);
up_write(&sbi->bio_read);
> +}
> +
> +void submit_read_page(struct f2fs_sb_info *sbi, struct page *page,
> + block_t blk_addr, int rw)
> +{
> + struct block_device *bdev = sbi->sb->s_bdev;
> + int bio_blocks;
> +
> + verify_block_addr(sbi, blk_addr);
> +
> + down_read(&sbi->bio_sem);
down_write(&sbi->bio_read);
> +
> + if (sbi->read_bio && sbi->last_read_block != blk_addr - 1) {
> + submit_bio(rw, sbi->read_bio);
> + sbi->read_bio = NULL;
> + }
> +
> +alloc_new:
> + if (sbi->read_bio == NULL) {
> + bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
> + sbi->read_bio = f2fs_bio_alloc(bdev, bio_blocks);
> + sbi->read_bio->bi_sector = SECTOR_FROM_BLOCK(sbi, blk_addr);
> + sbi->read_bio->bi_end_io = read_end_io;
> + }
> +
> + if (bio_add_page(sbi->read_bio, page, PAGE_CACHE_SIZE, 0) <
> + PAGE_CACHE_SIZE) {
> + submit_bio(rw, sbi->read_bio);
> + sbi->read_bio = NULL;
> + goto alloc_new;
> + }
> +
> + sbi->last_read_block = blk_addr;
> +
> + up_read(&sbi->bio_sem);
up_write(&sbi->bio_read);
> +}
> +
> /*
> * This function should be used by the data read flow only where it
> * does not check the "create" flag that indicates block allocation.
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 89dc750..bfe9d87 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -359,6 +359,8 @@ struct f2fs_sb_info {
>
> /* for segment-related operations */
> struct f2fs_sm_info *sm_info; /* segment manager */
> + struct bio *read_bio; /* read bios to merge */
> + sector_t last_read_block; /* last read block number */
> struct bio *bio[NR_PAGE_TYPE]; /* bios to merge */
> sector_t last_block_in_bio[NR_PAGE_TYPE]; /* last block number */
> struct rw_semaphore bio_sem; /* IO semaphore */
> @@ -1111,6 +1113,8 @@ struct page *find_data_page(struct inode *, pgoff_t, bool);
> struct page *get_lock_data_page(struct inode *, pgoff_t);
> struct page *get_new_data_page(struct inode *, struct page *, pgoff_t, bool);
> int f2fs_readpage(struct f2fs_sb_info *, struct page *, block_t, int);
> +void f2fs_submit_read_bio(struct f2fs_sb_info *, int);
> +void submit_read_page(struct f2fs_sb_info *, struct page *, block_t, int);
> int do_write_data_page(struct page *);
>
> /*
--
Jaegeuk Kim
Samsung
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH V2 1/2] f2fs: add a new function to support for merging contiguous read
2013-11-18 0:29 ` [f2fs-dev] " Jaegeuk Kim
@ 2013-11-18 1:37 ` Chao Yu
2013-11-18 9:11 ` Jaegeuk Kim
0 siblings, 1 reply; 6+ messages in thread
From: Chao Yu @ 2013-11-18 1:37 UTC (permalink / raw)
To: jaegeuk.kim; +Cc: linux-fsdevel, linux-kernel, linux-f2fs-devel
Hi Kim,
> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk.kim@samsung.com]
> Sent: Monday, November 18, 2013 8:29 AM
> To: Chao Yu
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; linux-f2fs-devel@lists.sourceforge.net; 谭姝
> Subject: Re: [f2fs-dev] [PATCH V2 1/2] f2fs: add a new function to support for merging contiguous read
>
> Hi Chao,
>
> 2013-11-16 (토), 14:14 +0800, Chao Yu:
> > For better read performance, we add a new function to support for merging contiguous read as the one for write.
>
> Please consider 80 columns for the description.
> I cannot fix this at every time though. :(
Got it, sorry about my carelessness in previous patch.
>
> >
> > v1-->v2:
> > o add declarations here as Gu Zheng suggested.
> >
> > Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> > Acked-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> > ---
> > fs/f2fs/data.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
> > fs/f2fs/f2fs.h | 4 ++++
> > 2 files changed, 49 insertions(+)
> >
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index aa3438c..18107cb 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -404,6 +404,51 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
> > return 0;
> > }
> >
> > +void f2fs_submit_read_bio(struct f2fs_sb_info *sbi, int rw)
> > +{
> > + down_read(&sbi->bio_sem);
>
> Is there any reason to use down_read()?
Isn't that we use bio_sem to let w/r or w/w submitting be mutex?
> It seems that we need to declare sbi->bio_read and sbi->bio_write
> instead of sbi->bio_sem.
> In addition to that, we need to use down_write(&sbi->bio_read) here.
If so, it looks similar between (struct rw_semaphore) sbi->bio_read
and (struct bio *) sbi->read_bio.
How about using read_bio_sem/rbio_sem to differentiate
from sbi->read_bio?
>
> > + if (sbi->read_bio) {
> > + submit_bio(rw, sbi->read_bio);
> > + sbi->read_bio = NULL;
> > + }
> > + up_read(&sbi->bio_sem);
>
> up_write(&sbi->bio_read);
>
> > +}
> > +
> > +void submit_read_page(struct f2fs_sb_info *sbi, struct page *page,
> > + block_t blk_addr, int rw)
> > +{
> > + struct block_device *bdev = sbi->sb->s_bdev;
> > + int bio_blocks;
> > +
> > + verify_block_addr(sbi, blk_addr);
> > +
> > + down_read(&sbi->bio_sem);
>
> down_write(&sbi->bio_read);
>
> > +
> > + if (sbi->read_bio && sbi->last_read_block != blk_addr - 1) {
> > + submit_bio(rw, sbi->read_bio);
> > + sbi->read_bio = NULL;
> > + }
> > +
> > +alloc_new:
> > + if (sbi->read_bio == NULL) {
> > + bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
> > + sbi->read_bio = f2fs_bio_alloc(bdev, bio_blocks);
> > + sbi->read_bio->bi_sector = SECTOR_FROM_BLOCK(sbi, blk_addr);
> > + sbi->read_bio->bi_end_io = read_end_io;
> > + }
> > +
> > + if (bio_add_page(sbi->read_bio, page, PAGE_CACHE_SIZE, 0) <
> > + PAGE_CACHE_SIZE) {
> > + submit_bio(rw, sbi->read_bio);
> > + sbi->read_bio = NULL;
> > + goto alloc_new;
> > + }
> > +
> > + sbi->last_read_block = blk_addr;
> > +
> > + up_read(&sbi->bio_sem);
>
> up_write(&sbi->bio_read);
>
> > +}
> > +
> > /*
> > * This function should be used by the data read flow only where it
> > * does not check the "create" flag that indicates block allocation.
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 89dc750..bfe9d87 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -359,6 +359,8 @@ struct f2fs_sb_info {
> >
> > /* for segment-related operations */
> > struct f2fs_sm_info *sm_info; /* segment manager */
> > + struct bio *read_bio; /* read bios to merge */
> > + sector_t last_read_block; /* last read block number */
> > struct bio *bio[NR_PAGE_TYPE]; /* bios to merge */
> > sector_t last_block_in_bio[NR_PAGE_TYPE]; /* last block number */
> > struct rw_semaphore bio_sem; /* IO semaphore */
> > @@ -1111,6 +1113,8 @@ struct page *find_data_page(struct inode *, pgoff_t, bool);
> > struct page *get_lock_data_page(struct inode *, pgoff_t);
> > struct page *get_new_data_page(struct inode *, struct page *, pgoff_t, bool);
> > int f2fs_readpage(struct f2fs_sb_info *, struct page *, block_t, int);
> > +void f2fs_submit_read_bio(struct f2fs_sb_info *, int);
> > +void submit_read_page(struct f2fs_sb_info *, struct page *, block_t, int);
> > int do_write_data_page(struct page *);
> >
> > /*
>
> --
> Jaegeuk Kim
> Samsung
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH V2 1/2] f2fs: add a new function to support for merging contiguous read
2013-11-18 1:37 ` Chao Yu
@ 2013-11-18 9:11 ` Jaegeuk Kim
2013-11-18 10:10 ` Gu Zheng
2013-11-19 1:41 ` Chao Yu
0 siblings, 2 replies; 6+ messages in thread
From: Jaegeuk Kim @ 2013-11-18 9:11 UTC (permalink / raw)
To: Chao Yu; +Cc: linux-fsdevel, linux-kernel, linux-f2fs-devel
Hi,
2013-11-18 (월), 09:37 +0800, Chao Yu:
> Hi Kim,
>
> > -----Original Message-----
> > From: Jaegeuk Kim [mailto:jaegeuk.kim@samsung.com]
> > Sent: Monday, November 18, 2013 8:29 AM
> > To: Chao Yu
> > Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; linux-f2fs-devel@lists.sourceforge.net; 谭姝
> > Subject: Re: [f2fs-dev] [PATCH V2 1/2] f2fs: add a new function to support for merging contiguous read
> >
> > Hi Chao,
> >
> > 2013-11-16 (토), 14:14 +0800, Chao Yu:
> > > For better read performance, we add a new function to support for merging contiguous read as the one for write.
> >
> > Please consider 80 columns for the description.
> > I cannot fix this at every time though. :(
>
> Got it, sorry about my carelessness in previous patch.
>
> >
> > >
> > > v1-->v2:
> > > o add declarations here as Gu Zheng suggested.
> > >
> > > Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> > > Acked-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> > > ---
> > > fs/f2fs/data.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
> > > fs/f2fs/f2fs.h | 4 ++++
> > > 2 files changed, 49 insertions(+)
> > >
> > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > > index aa3438c..18107cb 100644
> > > --- a/fs/f2fs/data.c
> > > +++ b/fs/f2fs/data.c
> > > @@ -404,6 +404,51 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
> > > return 0;
> > > }
> > >
> > > +void f2fs_submit_read_bio(struct f2fs_sb_info *sbi, int rw)
> > > +{
> > > + down_read(&sbi->bio_sem);
> >
> > Is there any reason to use down_read()?
>
> Isn't that we use bio_sem to let w/r or w/w submitting be mutex?
As I examined the bio_sem, I think we don't need to use a semaphore for
read and write IOs.
Just it is enough to use a mutex for writes only.
>
> > It seems that we need to declare sbi->bio_read and sbi->bio_write
> > instead of sbi->bio_sem.
> > In addition to that, we need to use down_write(&sbi->bio_read) here.
>
> If so, it looks similar between (struct rw_semaphore) sbi->bio_read
> and (struct bio *) sbi->read_bio.
> How about using read_bio_sem/rbio_sem to differentiate
> from sbi->read_bio?
I think sbi->write_mutex and sbi->read_mutex are much better.
Could you refer the following patches?
Thanks,
--
Jaegeuk Kim
Samsung
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH V2 1/2] f2fs: add a new function to support for merging contiguous read
2013-11-18 9:11 ` Jaegeuk Kim
@ 2013-11-18 10:10 ` Gu Zheng
2013-11-19 1:41 ` Chao Yu
1 sibling, 0 replies; 6+ messages in thread
From: Gu Zheng @ 2013-11-18 10:10 UTC (permalink / raw)
To: jaegeuk.kim; +Cc: linux-fsdevel, linux-kernel, linux-f2fs-devel
On 11/18/2013 05:11 PM, Jaegeuk Kim wrote:
> Hi,
>
> 2013-11-18 (월), 09:37 +0800, Chao Yu:
>> Hi Kim,
>>
>>> -----Original Message-----
>>> From: Jaegeuk Kim [mailto:jaegeuk.kim@samsung.com]
>>> Sent: Monday, November 18, 2013 8:29 AM
>>> To: Chao Yu
>>> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; linux-f2fs-devel@lists.sourceforge.net; 谭姝
>>> Subject: Re: [f2fs-dev] [PATCH V2 1/2] f2fs: add a new function to support for merging contiguous read
>>>
>>> Hi Chao,
>>>
>>> 2013-11-16 (토), 14:14 +0800, Chao Yu:
>>>> For better read performance, we add a new function to support for merging contiguous read as the one for write.
>>>
>>> Please consider 80 columns for the description.
>>> I cannot fix this at every time though. :(
>>
>> Got it, sorry about my carelessness in previous patch.
>>
>>>
>>>>
>>>> v1-->v2:
>>>> o add declarations here as Gu Zheng suggested.
>>>>
>>>> Signed-off-by: Chao Yu <chao2.yu@samsung.com>
>>>> Acked-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
>>>> ---
>>>> fs/f2fs/data.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
>>>> fs/f2fs/f2fs.h | 4 ++++
>>>> 2 files changed, 49 insertions(+)
>>>>
>>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>>> index aa3438c..18107cb 100644
>>>> --- a/fs/f2fs/data.c
>>>> +++ b/fs/f2fs/data.c
>>>> @@ -404,6 +404,51 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
>>>> return 0;
>>>> }
>>>>
>>>> +void f2fs_submit_read_bio(struct f2fs_sb_info *sbi, int rw)
>>>> +{
>>>> + down_read(&sbi->bio_sem);
>>>
>>> Is there any reason to use down_read()?
>>
>> Isn't that we use bio_sem to let w/r or w/w submitting be mutex?
>
> As I examined the bio_sem, I think we don't need to use a semaphore for
> read and write IOs.
> Just it is enough to use a mutex for writes only.
Agree. Mutex is more suitable here, we just want to protect the write bio
related fields in the write patch, no relations to read.
>
>>
>>> It seems that we need to declare sbi->bio_read and sbi->bio_write
>>> instead of sbi->bio_sem.
>>> In addition to that, we need to use down_write(&sbi->bio_read) here.
>>
>> If so, it looks similar between (struct rw_semaphore) sbi->bio_read
>> and (struct bio *) sbi->read_bio.
>> How about using read_bio_sem/rbio_sem to differentiate
>> from sbi->read_bio?
>
> I think sbi->write_mutex and sbi->read_mutex are much better.
It's more reasonable and readable.
Thanks,
Gu
>
> Could you refer the following patches?
> Thanks,
>
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH V2 1/2] f2fs: add a new function to support for merging contiguous read
2013-11-18 9:11 ` Jaegeuk Kim
2013-11-18 10:10 ` Gu Zheng
@ 2013-11-19 1:41 ` Chao Yu
1 sibling, 0 replies; 6+ messages in thread
From: Chao Yu @ 2013-11-19 1:41 UTC (permalink / raw)
To: jaegeuk.kim; +Cc: linux-fsdevel, linux-kernel, linux-f2fs-devel
Hi
> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk.kim@samsung.com]
> Sent: Monday, November 18, 2013 5:11 PM
> To: Chao Yu
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net; '谭姝'
> Subject: RE: [f2fs-dev] [PATCH V2 1/2] f2fs: add a new function to support for
> merging contiguous read
>
> Hi,
>
> 2013-11-18 (월), 09:37 +0800, Chao Yu:
> > Hi Kim,
> >
> > > -----Original Message-----
> > > From: Jaegeuk Kim [mailto:jaegeuk.kim@samsung.com]
> > > Sent: Monday, November 18, 2013 8:29 AM
> > > To: Chao Yu
> > > Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net; 谭姝
> > > Subject: Re: [f2fs-dev] [PATCH V2 1/2] f2fs: add a new function to support for
> merging contiguous read
> > >
> > > Hi Chao,
> > >
> > > 2013-11-16 (토), 14:14 +0800, Chao Yu:
> > > > For better read performance, we add a new function to support for merging
> contiguous read as the one for write.
> > >
> > > Please consider 80 columns for the description.
> > > I cannot fix this at every time though. :(
> >
> > Got it, sorry about my carelessness in previous patch.
> >
> > >
> > > >
> > > > v1-->v2:
> > > > o add declarations here as Gu Zheng suggested.
> > > >
> > > > Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> > > > Acked-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> > > > ---
> > > > fs/f2fs/data.c | 45
> +++++++++++++++++++++++++++++++++++++++++++++
> > > > fs/f2fs/f2fs.h | 4 ++++
> > > > 2 files changed, 49 insertions(+)
> > > >
> > > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > > > index aa3438c..18107cb 100644
> > > > --- a/fs/f2fs/data.c
> > > > +++ b/fs/f2fs/data.c
> > > > @@ -404,6 +404,51 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct
> page *page,
> > > > return 0;
> > > > }
> > > >
> > > > +void f2fs_submit_read_bio(struct f2fs_sb_info *sbi, int rw)
> > > > +{
> > > > + down_read(&sbi->bio_sem);
> > >
> > > Is there any reason to use down_read()?
> >
> > Isn't that we use bio_sem to let w/r or w/w submitting be mutex?
>
> As I examined the bio_sem, I think we don't need to use a semaphore for
> read and write IOs.
> Just it is enough to use a mutex for writes only.
Agreed, it could also improve efficiency of read/write request concurrent.
>
> >
> > > It seems that we need to declare sbi->bio_read and sbi->bio_write
> > > instead of sbi->bio_sem.
> > > In addition to that, we need to use down_write(&sbi->bio_read) here.
> >
> > If so, it looks similar between (struct rw_semaphore) sbi->bio_read
> > and (struct bio *) sbi->read_bio.
> > How about using read_bio_sem/rbio_sem to differentiate
> > from sbi->read_bio?
>
> I think sbi->write_mutex and sbi->read_mutex are much better.
>
> Could you refer the following patches?
It's better, I will refer your patch.
And how about this following patch to reduce race of write_mutex
between DATA/NODE/META writer?
> Thanks,
>
> --
> Jaegeuk Kim
> Samsung
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^ permalink raw reply [flat|nested] 6+ messages in thread
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Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-11-16 6:14 [PATCH V2 1/2] f2fs: add a new function to support for merging contiguous read Chao Yu
2013-11-18 0:29 ` [f2fs-dev] " Jaegeuk Kim
2013-11-18 1:37 ` Chao Yu
2013-11-18 9:11 ` Jaegeuk Kim
2013-11-18 10:10 ` Gu Zheng
2013-11-19 1:41 ` Chao Yu
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