linux-kernel - Re: [PATCH v2 7/7] mm/compaction: factor out code to test if we should run compaction for target order

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Date:   Wed, 30 Aug 2023 14:28:27 +0800
From:   Kemeng Shi <shikemeng@...weicloud.com>
To:     Baolin Wang <baolin.wang@...ux.alibaba.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
        mgorman@...hsingularity.net, david@...hat.com, willy@...radead.org
Subject: Re: [PATCH v2 7/7] mm/compaction: factor out code to test if we
 should run compaction for target order



on 8/29/2023 11:48 AM, Baolin Wang wrote:
> 
> 
> On 8/26/2023 11:36 PM, Kemeng Shi wrote:
>> We always do zone_watermark_ok check and compaction_suitable check
>> together to test if compaction for target order should be runned.
>> Factor these code out to remove repeat code.
>>
>> Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com>
>> ---
>>   mm/compaction.c | 63 ++++++++++++++++++++++++++++---------------------
>>   1 file changed, 36 insertions(+), 27 deletions(-)
>>
>> diff --git a/mm/compaction.c b/mm/compaction.c
>> index 00b7bba6c72e..6f2b87b026b8 100644
>> --- a/mm/compaction.c
>> +++ b/mm/compaction.c
>> @@ -2374,6 +2374,30 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
>>       return false;
>>   }
>>   +/*
>> + * Should we do compaction for target allocation order.
>> + * Return COMPACT_SUCCESS if allocation for target order can be already
>> + * satisfied
>> + * Return COMPACT_SKIPPED if compaction for target order is likely to fail
>> + * Return COMPACT_CONTINUE if compaction for target order should be runned
>> + */
>> +static inline enum compact_result
> 
> I think you should drop the 'inline' to let the compiler make the decision.
> 
Sure, I will drop this in next version. Thanks for feedback.
>> +compaction_suit_allocation_order(struct zone *zone, unsigned int order,
>> +                 int highest_zoneidx, unsigned int alloc_flags)
> 
> The changes look good to me. So please feel free to add:
> Reviewed-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
> 
>> +{
>> +    unsigned long watermark;
>> +
>> +    watermark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK);
>> +    if (zone_watermark_ok(zone, order, watermark, highest_zoneidx,
>> +                  alloc_flags))
>> +        return COMPACT_SUCCESS;
>> +
>> +    if (!compaction_suitable(zone, order, highest_zoneidx))
>> +        return COMPACT_SKIPPED;
>> +
>> +    return COMPACT_CONTINUE;
>> +}
>> +
>>   static enum compact_result
>>   compact_zone(struct compact_control *cc, struct capture_control *capc)
>>   {
>> @@ -2399,19 +2423,11 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
>>       cc->migratetype = gfp_migratetype(cc->gfp_mask);
>>         if (!is_via_compact_memory(cc->order)) {
>> -        unsigned long watermark;
>> -
>> -        /* Allocation can already succeed, nothing to do */
>> -        watermark = wmark_pages(cc->zone,
>> -                    cc->alloc_flags & ALLOC_WMARK_MASK);
>> -        if (zone_watermark_ok(cc->zone, cc->order, watermark,
>> -                      cc->highest_zoneidx, cc->alloc_flags))
>> -            return COMPACT_SUCCESS;
>> -
>> -        /* Compaction is likely to fail */
>> -        if (!compaction_suitable(cc->zone, cc->order,
>> -                     cc->highest_zoneidx))
>> -            return COMPACT_SKIPPED;
>> +        ret = compaction_suit_allocation_order(cc->zone, cc->order,
>> +                               cc->highest_zoneidx,
>> +                               cc->alloc_flags);
>> +        if (ret != COMPACT_CONTINUE)
>> +            return ret;
>>       }
>>         /*
>> @@ -2917,14 +2933,10 @@ static bool kcompactd_node_suitable(pg_data_t *pgdat)
>>           if (!populated_zone(zone))
>>               continue;
>>   -        /* Allocation can already succeed, check other zones */
>> -        if (zone_watermark_ok(zone, pgdat->kcompactd_max_order,
>> -                      min_wmark_pages(zone),
>> -                      highest_zoneidx, 0))
>> -            continue;
>> -
>> -        if (compaction_suitable(zone, pgdat->kcompactd_max_order,
>> -                    highest_zoneidx))
>> +        if (compaction_suit_allocation_order(zone,
>> +                pgdat->kcompactd_max_order,
>> +                highest_zoneidx, ALLOC_WMARK_MIN) ==
>> +                COMPACT_CONTINUE)
>>               return true;
>>       }
>>   @@ -2961,12 +2973,9 @@ static void kcompactd_do_work(pg_data_t *pgdat)
>>           if (compaction_deferred(zone, cc.order))
>>               continue;
>>   -        /* Allocation can already succeed, nothing to do */
>> -        if (zone_watermark_ok(zone, cc.order,
>> -                      min_wmark_pages(zone), zoneid, 0))
>> -            continue;
>> -
>> -        if (!compaction_suitable(zone, cc.order, zoneid))
>> +        if (compaction_suit_allocation_order(zone,
>> +                cc.order, zoneid, ALLOC_WMARK_MIN) !=
>> +                COMPACT_CONTINUE)
>>               continue;
>>             if (kthread_should_stop())
>