linux-kernel - Re: [PATCH] mm: ALLOC_HIGHATOMIC flag allocation issue

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Message-ID: <f4fbe385-3a31-4d8d-ba3b-409f3f03c7c9@vivo.com>
Date:   Tue, 21 Nov 2023 10:26:18 +0800
From:   zhiguojiang <justinjiang@...o.com>
To:     Matthew Wilcox <willy@...radead.org>
Cc:     Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Johannes Weiner <hannes@...xchg.org>,
        opensource.kernel@...o.com
Subject: Re: [PATCH] mm: ALLOC_HIGHATOMIC flag allocation issue


Thanks, I have updated the related modifications according to  your 
suggestions in patch v2.

在 2023/11/21 1:29, Matthew Wilcox 写道:
> On Mon, Nov 20, 2023 at 10:35:36AM +0800, Zhiguo Jiang wrote:
>> +			/*
>> +			 * If pcplist is empty and alloc_flags is with ALLOC_HIGHATOMIC,
>> +			 * it should alloc from buddy highatomic migrate freelist firstly
>> +			 * to ensure quick and successful allocation.
> Assuming that all the serious question shave been dealt with, let's
> fix the less important problems ...
>
> 			 * If pcplist is empty and alloc_flags contains
> 			 * ALLOC_HIGHATOMIC, alloc from buddy highatomic
> 			 * freelist first.
>
>> @@ -2918,7 +2927,7 @@ static inline
>>   struct page *rmqueue(struct zone *preferred_zone,
>>   			struct zone *zone, unsigned int order,
>>   			gfp_t gfp_flags, unsigned int alloc_flags,
>> -			int migratetype)
>> +			int migratetype, bool *highatomc_allocation)
> bool *highatomic
>
>> +	/*
>> +	 * The high-order atomic allocation pageblock reserved conditions:
>> +	 *
>> +	 * If the high-order atomic allocation page is alloced from pcplist,
>> +	 * the highatomic pageblock does not need to be reserved, which can
>> +	 * void to migrate an increasing number of pages into buddy
> 	 * avoid migrating an increasing number of pages into buddy
>
>> +	 * MIGRATE_HIGHATOMIC freelist and lead to an increasing risk of
> "increased"
>
>> +	 * allocation failure on other buddy migrate freelists.
>> +	 *
>> +	 * If the high-order atomic allocation page is alloced from buddy
> "allocated"
>
>> @@ -3208,6 +3234,7 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
>>   	struct pglist_data *last_pgdat = NULL;
>>   	bool last_pgdat_dirty_ok = false;
>>   	bool no_fallback;
>> +	bool highatomc_allocation = false;
> Again, just call this 'highatomic'.
>