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Subject: Re: [PATCH] blk-throttle: Fix incorrect display of io.max
To: Waiman Long <longman@redhat.com>, Jens Axboe <axboe@kernel.dk>,
 Tejun Heo <tj@kernel.org>, Josef Bacik <josef@toxicpanda.com>
Cc: cgroups@vger.kernel.org, linux-block@vger.kernel.org,
 linux-kernel@vger.kernel.org, Dan Schatzberg <schatzberg.dan@gmail.com>,
 Ming Lei <ming.lei@redhat.com>, Justin Forbes <jforbes@redhat.com>,
 "yukuai (C)" <yukuai3@huawei.com>
References: <20240530134547.970075-1-longman@redhat.com>
 <0de07021-df77-4196-bb75-9ded88b74ce2@redhat.com>
From: Yu Kuai <yukuai1@huaweicloud.com>
Message-ID: <8191bb3d-2afd-ab76-c8b4-50f2871b7a9d@huaweicloud.com>
Date: Fri, 31 May 2024 09:21:22 +0800
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在 2024/05/30 21:49, Waiman Long 写道:
> 
> On 5/30/24 09:45, Waiman Long wrote:
>> Commit bf20ab538c81 ("blk-throttle: remove 
>> CONFIG_BLK_DEV_THROTTLING_LOW")
>> attempts to revert the code change introduced by commit cd5ab1b0fcb4
>> ("blk-throttle: add .low interface").  However, it leaves behind the
>> bps_conf[] and iops_conf[] fields in the throtl_grp structure which
>> aren't set anywhere in the new blk-throttle.c code but are still being
>> used by tg_prfill_limit() to display the limits in io.max. Now io.max
>> always displays the following values if a block queue is used:
>>
>>     <m>:<n> rbps=0 wbps=0 riops=0 wiops=0
>>
>> Fix this problem by removing bps_conf[] and iops_conf[] and use bps[]
>> and iops[] instead to complete the revert.
>>
>> Fixes: bf20ab538c81 ("blk-throttle: remove 
>> CONFIG_BLK_DEV_THROTTLING_LOW")
>> Reported-by: Justin Forbes <jforbes@redhat.com>
>> Closes: 
>> https://github.com/containers/podman/issues/22701#issuecomment-2120627789
>> Signed-off-by: Waiman Long <longman@redhat.com>

LGTM
Reviewed-by: Yu Kuai <yukuai3@huawei.com>

>> ---
>>   block/blk-throttle.c | 24 ++++++++++++------------
>>   block/blk-throttle.h |  8 ++------
>>   2 files changed, 14 insertions(+), 18 deletions(-)
>>
>> diff --git a/block/blk-throttle.c b/block/blk-throttle.c
>> index d907040859f9..da619654f418 100644
>> --- a/block/blk-throttle.c
>> +++ b/block/blk-throttle.c
>> @@ -1347,32 +1347,32 @@ static u64 tg_prfill_limit(struct seq_file 
>> *sf, struct blkg_policy_data *pd,
>>       bps_dft = U64_MAX;
>>       iops_dft = UINT_MAX;
>> -    if (tg->bps_conf[READ] == bps_dft &&
>> -        tg->bps_conf[WRITE] == bps_dft &&
>> -        tg->iops_conf[READ] == iops_dft &&
>> -        tg->iops_conf[WRITE] == iops_dft)
>> +    if (tg->bps[READ] == bps_dft &&
>> +        tg->bps[WRITE] == bps_dft &&
>> +        tg->iops[READ] == iops_dft &&
>> +        tg->iops[WRITE] == iops_dft)
>>           return 0;
>>       seq_printf(sf, "%s", dname);
>> -    if (tg->bps_conf[READ] == U64_MAX)
>> +    if (tg->bps[READ] == U64_MAX)
>>           seq_printf(sf, " rbps=max");
>>       else
>> -        seq_printf(sf, " rbps=%llu", tg->bps_conf[READ]);
>> +        seq_printf(sf, " rbps=%llu", tg->bps[READ]);
>> -    if (tg->bps_conf[WRITE] == U64_MAX)
>> +    if (tg->bps[WRITE] == U64_MAX)
>>           seq_printf(sf, " wbps=max");
>>       else
>> -        seq_printf(sf, " wbps=%llu", tg->bps_conf[WRITE]);
>> +        seq_printf(sf, " wbps=%llu", tg->bps[WRITE]);
>> -    if (tg->iops_conf[READ] == UINT_MAX)
>> +    if (tg->iops[READ] == UINT_MAX)
>>           seq_printf(sf, " riops=max");
>>       else
>> -        seq_printf(sf, " riops=%u", tg->iops_conf[READ]);
>> +        seq_printf(sf, " riops=%u", tg->iops[READ]);
>> -    if (tg->iops_conf[WRITE] == UINT_MAX)
>> +    if (tg->iops[WRITE] == UINT_MAX)
>>           seq_printf(sf, " wiops=max");
>>       else
>> -        seq_printf(sf, " wiops=%u", tg->iops_conf[WRITE]);
>> +        seq_printf(sf, " wiops=%u", tg->iops[WRITE]);
>>       seq_printf(sf, "\n");
>>       return 0;
>> diff --git a/block/blk-throttle.h b/block/blk-throttle.h
>> index 32503fd83a84..8c365541a275 100644
>> --- a/block/blk-throttle.h
>> +++ b/block/blk-throttle.h
>> @@ -95,15 +95,11 @@ struct throtl_grp {
>>       bool has_rules_bps[2];
>>       bool has_rules_iops[2];
>> -    /* internally used bytes per second rate limits */
>> +    /* bytes per second rate limits */
>>       uint64_t bps[2];
>> -    /* user configured bps limits */
>> -    uint64_t bps_conf[2];
>> -    /* internally used IOPS limits */
>> +    /* IOPS limits */
>>       unsigned int iops[2];
>> -    /* user configured IOPS limits */
>> -    unsigned int iops_conf[2];
>>       /* Number of bytes dispatched in current slice */
>>       uint64_t bytes_disp[2];
> 
> Add Yu Kuai <yukuai3@huawei.com> to cc.
> 
> 
> .
>