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[PATCH v2 10/10] ext4: correct some stale comment of criteria

Kemeng Shi posted 10 patches 2 years, 6 months ago
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[PATCH v2 10/10] ext4: correct some stale comment of criteria
Posted by Kemeng Shi 2 years, 6 months ago 
We named criteria with CR_XXX, correct stale comment to criteria with
raw number.

Fixes: f52f3d2b9fba ("ext4: Give symbolic names to mballoc criterias")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
---
 fs/ext4/mballoc.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 36eea63eaace..de5da76e6748 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2777,8 +2777,8 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
 
 	/*
 	 * ac->ac_2order is set only if the fe_len is a power of 2
-	 * if ac->ac_2order is set we also set criteria to 0 so that we
-	 * try exact allocation using buddy.
+	 * if ac->ac_2order is set we also set criteria to CR_POWER2_ALIGNED
+	 * so that we try exact allocation using buddy.
 	 */
 	i = fls(ac->ac_g_ex.fe_len);
 	ac->ac_2order = 0;
@@ -2835,8 +2835,8 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
 			/*
 			 * Batch reads of the block allocation bitmaps
 			 * to get multiple READs in flight; limit
-			 * prefetching at cr=0/1, otherwise mballoc can
-			 * spend a lot of time loading imperfect groups
+			 * prefetching at cr below CR_FAST, otherwise mballoc
+			 * can spend a lot of time loading imperfect groups
 			 */
 			if ((prefetch_grp == group) &&
 			    (cr >= CR_FAST ||
-- 
2.30.0
Re: [PATCH v2 10/10] ext4: correct some stale comment of criteria
Posted by Ojaswin Mujoo 2 years, 6 months ago 
On Wed, Jul 26, 2023 at 02:51:06AM +0800, Kemeng Shi wrote:
> We named criteria with CR_XXX, correct stale comment to criteria with
> raw number.

Hi Kemeng,

Thanks for the cleanups.

> 
> Fixes: f52f3d2b9fba ("ext4: Give symbolic names to mballoc criterias")
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
> ---
>  fs/ext4/mballoc.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 36eea63eaace..de5da76e6748 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -2777,8 +2777,8 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
>  
>  	/*
>  	 * ac->ac_2order is set only if the fe_len is a power of 2
> -	 * if ac->ac_2order is set we also set criteria to 0 so that we
> -	 * try exact allocation using buddy.
> +	 * if ac->ac_2order is set we also set criteria to CR_POWER2_ALIGNED
> +	 * so that we try exact allocation using buddy.
>  	 */
>  	i = fls(ac->ac_g_ex.fe_len);
>  	ac->ac_2order = 0;
> @@ -2835,8 +2835,8 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
>  			/*
>  			 * Batch reads of the block allocation bitmaps
>  			 * to get multiple READs in flight; limit
> -			 * prefetching at cr=0/1, otherwise mballoc can
> -			 * spend a lot of time loading imperfect groups
> +			 * prefetching at cr below CR_FAST, otherwise mballoc

One of my earlier patchset has replaced the CR_FAST macro with
ext4_mb_cr_expensive() so maybe we can account for that here:

https://lore.kernel.org/linux-ext4/20230630085927.140137-1-ojaswin@linux.ibm.com/

Regards,
ojaswin

> +			 * can spend a lot of time loading imperfect groups

>  			 */
>  			if ((prefetch_grp == group) &&
>  			    (cr >= CR_FAST ||
> -- 
> 2.30.0
>
Re: [PATCH v2 10/10] ext4: correct some stale comment of criteria
Posted by Kemeng Shi 2 years, 6 months ago 

on 7/26/2023 10:50 PM, Ojaswin Mujoo wrote:
> On Wed, Jul 26, 2023 at 02:51:06AM +0800, Kemeng Shi wrote:
>> We named criteria with CR_XXX, correct stale comment to criteria with
>> raw number.
> 
> Hi Kemeng,
> 
> Thanks for the cleanups.
> 
>>
>> Fixes: f52f3d2b9fba ("ext4: Give symbolic names to mballoc criterias")
>> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
>> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
>> ---
>>  fs/ext4/mballoc.c | 8 ++++----
>>  1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
>> index 36eea63eaace..de5da76e6748 100644
>> --- a/fs/ext4/mballoc.c
>> +++ b/fs/ext4/mballoc.c
>> @@ -2777,8 +2777,8 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
>>  
>>  	/*
>>  	 * ac->ac_2order is set only if the fe_len is a power of 2
>> -	 * if ac->ac_2order is set we also set criteria to 0 so that we
>> -	 * try exact allocation using buddy.
>> +	 * if ac->ac_2order is set we also set criteria to CR_POWER2_ALIGNED
>> +	 * so that we try exact allocation using buddy.
>>  	 */
>>  	i = fls(ac->ac_g_ex.fe_len);
>>  	ac->ac_2order = 0;
>> @@ -2835,8 +2835,8 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
>>  			/*
>>  			 * Batch reads of the block allocation bitmaps
>>  			 * to get multiple READs in flight; limit
>> -			 * prefetching at cr=0/1, otherwise mballoc can
>> -			 * spend a lot of time loading imperfect groups
>> +			 * prefetching at cr below CR_FAST, otherwise mballoc
> 
> One of my earlier patchset has replaced the CR_FAST macro with
> ext4_mb_cr_expensive() so maybe we can account for that here:
> 
> https://lore.kernel.org/linux-ext4/20230630085927.140137-1-ojaswin@linux.ibm.com/
> 
Hi Ojaswin, sorry for missing this. I still could not find the comment update
of stale comment "limit prefetching at cr=0/1" in that patch. Maybe we could
update comment to "prefetching at inexpensive CR, otherwise ...". What do
you think. Or did I miss anything.

-- 
Best wishes
Kemeng Shi
> Regards,
> ojaswin
> 
>> +			 * can spend a lot of time loading imperfect groups
> 
>>  			 */
>>  			if ((prefetch_grp == group) &&
>>  			    (cr >= CR_FAST ||
>> -- 
>> 2.30.0
>>
>
Re: [PATCH v2 10/10] ext4: correct some stale comment of criteria
Posted by Ojaswin Mujoo 2 years, 6 months ago 
On Thu, Jul 27, 2023 at 09:29:11AM +0800, Kemeng Shi wrote:
> 
> 
> on 7/26/2023 10:50 PM, Ojaswin Mujoo wrote:
> > On Wed, Jul 26, 2023 at 02:51:06AM +0800, Kemeng Shi wrote:
> >> We named criteria with CR_XXX, correct stale comment to criteria with
> >> raw number.
> > 
> > Hi Kemeng,
> > 
> > Thanks for the cleanups.
> > 
> >>
> >> Fixes: f52f3d2b9fba ("ext4: Give symbolic names to mballoc criterias")
> >> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
> >> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
> >> ---
> >>  fs/ext4/mballoc.c | 8 ++++----
> >>  1 file changed, 4 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> >> index 36eea63eaace..de5da76e6748 100644
> >> --- a/fs/ext4/mballoc.c
> >> +++ b/fs/ext4/mballoc.c
> >> @@ -2777,8 +2777,8 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
> >>  
> >>  	/*
> >>  	 * ac->ac_2order is set only if the fe_len is a power of 2
> >> -	 * if ac->ac_2order is set we also set criteria to 0 so that we
> >> -	 * try exact allocation using buddy.
> >> +	 * if ac->ac_2order is set we also set criteria to CR_POWER2_ALIGNED
> >> +	 * so that we try exact allocation using buddy.
> >>  	 */
> >>  	i = fls(ac->ac_g_ex.fe_len);
> >>  	ac->ac_2order = 0;
> >> @@ -2835,8 +2835,8 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
> >>  			/*
> >>  			 * Batch reads of the block allocation bitmaps
> >>  			 * to get multiple READs in flight; limit
> >> -			 * prefetching at cr=0/1, otherwise mballoc can
> >> -			 * spend a lot of time loading imperfect groups
> >> +			 * prefetching at cr below CR_FAST, otherwise mballoc
> > 
> > One of my earlier patchset has replaced the CR_FAST macro with
> > ext4_mb_cr_expensive() so maybe we can account for that here:
> > 
> > https://lore.kernel.org/linux-ext4/20230630085927.140137-1-ojaswin@linux.ibm.com/
> > 
> Hi Ojaswin, sorry for missing this. I still could not find the comment update
> of stale comment "limit prefetching at cr=0/1" in that patch. Maybe we could
> update comment to "prefetching at inexpensive CR, otherwise ...". What do
> you think. Or did I miss anything.

Hey Kemeng,

That's right I missed the update but just wanted to let you know that
CR_FAST would be removed. "prefetching at inexpensive CRs, ..."  sounds
good to me.

Regards,
ojaswin
> 
> -- 
> Best wishes
> Kemeng Shi
> > Regards,
> > ojaswin
> > 
> >> +			 * can spend a lot of time loading imperfect groups
> > 
> >>  			 */
> >>  			if ((prefetch_grp == group) &&
> >>  			    (cr >= CR_FAST ||
> >> -- 
> >> 2.30.0
> >>
> >
>

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