linux-kernel - Re: [PATCH][v4] mm/hugetlb: retry to allocate for early boot hugepage allocation

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Message-ID: <9a85a903-ac8d-4198-a8d4-01d70f23b443@redhat.com>
Date: Mon, 1 Sep 2025 12:10:49 +0200
From: David Hildenbrand <david@...hat.com>
To: lirongqing <lirongqing@...du.com>, muchun.song@...ux.dev,
 osalvador@...e.de, akpm@...ux-foundation.org, linux-mm@...ck.org,
 linux-kernel@...r.kernel.org, giorgitchankvetadze1997@...il.com
Subject: Re: [PATCH][v4] mm/hugetlb: retry to allocate for early boot hugepage
 allocation

On 01.09.25 10:20, lirongqing wrote:
> From: Li RongQing <lirongqing@...du.com>
> 
> In cloud environments with massive hugepage reservations (95%+ of system
> RAM), single-attempt allocation during early boot often fails due to
> memory pressure.
> 
> Commit 91f386bf0772 ("hugetlb: batch freeing of vmemmap pages") intensified
> this by deferring page frees, increase peak memory usage during allocation.
> 
> Introduce a retry mechanism that leverages vmemmap optimization reclaim
> (~1.6% memory) when available. Upon initial allocation failure, the system
> retries until successful or no further progress is made, ensuring reliable
> hugepage allocation while preserving batched vmemmap freeing benefits.
> 
> Testing on a 256G machine allocating 252G of hugepages:
> Before: 128056/129024 hugepages allocated
> After:  Successfully allocated all 129024 hugepages
> 
> Suggested-by: David Hildenbrand <david@...hat.com>
> Signed-off-by: Li RongQing <lirongqing@...du.com>
> ---

Thanks! BTW, it's interesting to see such extreme hugetlb allocation on 
machines :)

Acked-by: David Hildenbrand <david@...hat.com>

-- 
Cheers

David / dhildenb