Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <bf5b8a5b-4a0f-a258-f0ba-5339b7382ec6@linux.alibaba.com>
Date:   Fri, 16 Sep 2022 14:39:19 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0)
 Gecko/20100101 Thunderbird/102.2.1
Subject: Re: [PATCH] mm/hugetlb: add mis_resv_equal_free() func
To:     mike.kravetz@oracle.com
Cc:     songmuchun@bytedance.com, akpm@linux-foundation.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
References: <20220916063550.1650-1-xhao@linux.alibaba.com>
From:   haoxin <xhao@linux.alibaba.com>
In-Reply-To: <20220916063550.1650-1-xhao@linux.alibaba.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk


在 2022/9/16 下午2:35, Xin Hao 写道:
> In hugetlb.c file, there are several places to compare the values of
> 'h->free_huge_pages' and 'h->resv_huge_pages', it looks a bit messy, so
> there add a new mis_resv_equal_free() func to do these.
Sorry there make a mistake,  it add an extra letter 'm' 
mis_resv_equal_free,  i will send a new version,  please ignore this patch.
>
> Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
> ---
>   mm/hugetlb.c | 14 +++++++++-----
>   1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 66496fc424f4..db6f63fb083f 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1191,6 +1191,11 @@ static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask,
>   	return NULL;
>   }
>   
> +static inline bool is_resv_equal_free(struct hstate *h)
> +{
> +	return (h->free_huge_pages - h->resv_huge_pages == 0) ? true : false;
> +}
> +
>   static struct page *dequeue_huge_page_vma(struct hstate *h,
>   				struct vm_area_struct *vma,
>   				unsigned long address, int avoid_reserve,
> @@ -1207,12 +1212,11 @@ static struct page *dequeue_huge_page_vma(struct hstate *h,
>   	 * have no page reserves. This check ensures that reservations are
>   	 * not "stolen". The child may still get SIGKILLed
>   	 */
> -	if (!vma_has_reserves(vma, chg) &&
> -			h->free_huge_pages - h->resv_huge_pages == 0)
> +	if (!vma_has_reserves(vma, chg) && is_resv_equal_free(h))
>   		goto err;
>   
>   	/* If reserves cannot be used, ensure enough pages are in the pool */
> -	if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
> +	if (avoid_reserve && is_resv_equal_free(h))
>   		goto err;
>   
>   	gfp_mask = htlb_alloc_mask(h);
> @@ -2105,7 +2109,7 @@ int dissolve_free_huge_page(struct page *page)
>   	if (!page_count(page)) {
>   		struct page *head = compound_head(page);
>   		struct hstate *h = page_hstate(head);
> -		if (h->free_huge_pages - h->resv_huge_pages == 0)
> +		if (is_resv_equal_free(h))
>   			goto out;
>   
>   		/*
> @@ -2315,7 +2319,7 @@ struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
>   		nodemask_t *nmask, gfp_t gfp_mask)
>   {
>   	spin_lock_irq(&hugetlb_lock);
> -	if (h->free_huge_pages - h->resv_huge_pages > 0) {
> +	if (!is_resv_equal_free(h)) {
>   		struct page *page;
>   
>   		page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);