From: Oscar Salvador <osalvador@suse.de>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
David Hildenbrand <david@redhat.com>,
Michal Hocko <mhocko@suse.com>, Zi Yan <ziy@nvidia.com>,
Muchun Song <songmuchun@bytedance.com>,
Naoya Horiguchi <naoya.horiguchi@linux.dev>,
David Rientjes <rientjes@google.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v3 1/5] hugetlb: add demote hugetlb page sysfs interfaces
Date: Mon, 4 Oct 2021 15:00:59 +0200 [thread overview]
Message-ID: <YVr7C8ek1g9hKz4C@localhost.localdomain> (raw)
In-Reply-To: <20211001175210.45968-2-mike.kravetz@oracle.com>
On Fri, Oct 01, 2021 at 10:52:06AM -0700, Mike Kravetz wrote:
> -which function as described above for the default huge page-sized case.
> +The demote interfaces provide the ability to split a huge page into
> +smaller huge pages. For example, the x86 architecture supports both
> +1GB and 2MB huge pages sizes. A 1GB huge page can be split into 512
> +2MB huge pages. Demote interfaces are not available for the smallest
> +huge page size. The demote interfaces are:
> +
> +demote_size
> + is the size of demoted pages. When a page is demoted a corresponding
> + number of huge pages of demote_size will be created. By default,
> + demote_size is set to the next smaller huge page size. If there are
> + multiple smaller huge page sizes, demote_size can be set to any of
> + these smaller sizes. Only huge page sizes less then the current huge
s/then/than ?
> static void __init hugetlb_init_hstates(void)
> {
> - struct hstate *h;
> + struct hstate *h, *h2;
>
> for_each_hstate(h) {
> if (minimum_order > huge_page_order(h))
> @@ -2995,6 +2995,23 @@ static void __init hugetlb_init_hstates(void)
> /* oversize hugepages were init'ed in early boot */
> if (!hstate_is_gigantic(h))
> hugetlb_hstate_alloc_pages(h);
> +
> + /*
> + * Set demote order for each hstate. Note that
> + * h->demote_order is initially 0.
> + * - We can not demote gigantic pages if runtime freeing
> + * is not supported.
> + */
> + if (!hstate_is_gigantic(h) ||
> + gigantic_page_runtime_supported()) {
Based on the comment, I think that making the condition explicit looks
better from my point of view.
if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
continue;
> + for_each_hstate(h2) {
> + if (h2 == h)
> + continue;
> + if (h2->order < h->order &&
> + h2->order > h->demote_order)
> + h->demote_order = h2->order;
> + }
> + }
> }
> VM_BUG_ON(minimum_order == UINT_MAX);
> }
> @@ -3235,9 +3252,29 @@ static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
> return 0;
> }
>
--
Oscar Salvador
SUSE L3
next prev parent reply other threads:[~2021-10-04 13:01 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-01 17:52 [PATCH v3 0/5] hugetlb: add demote/split page functionality Mike Kravetz
2021-10-01 17:52 ` [PATCH v3 1/5] hugetlb: add demote hugetlb page sysfs interfaces Mike Kravetz
2021-10-04 13:00 ` Oscar Salvador [this message]
2021-10-04 18:27 ` Mike Kravetz
2021-10-05 8:23 ` Oscar Salvador
2021-10-05 16:58 ` Mike Kravetz
2021-10-01 17:52 ` [PATCH v3 2/5] mm/cma: add cma_pages_valid to determine if pages are in CMA Mike Kravetz
2021-10-05 8:45 ` Oscar Salvador
2021-10-05 17:06 ` Mike Kravetz
2021-10-05 8:48 ` David Hildenbrand
2021-10-01 17:52 ` [PATCH v3 3/5] hugetlb: be sure to free demoted CMA pages to CMA Mike Kravetz
2021-10-05 9:33 ` Oscar Salvador
2021-10-05 18:57 ` Mike Kravetz
2021-10-06 7:54 ` Oscar Salvador
2021-10-06 18:27 ` Mike Kravetz
2021-10-01 17:52 ` [PATCH v3 4/5] hugetlb: add demote bool to gigantic page routines Mike Kravetz
2021-10-01 17:52 ` [PATCH v3 5/5] hugetlb: add hugetlb demote page support Mike Kravetz
2021-10-06 8:41 ` Oscar Salvador
2021-10-06 18:52 ` Mike Kravetz
2021-10-07 7:52 ` Oscar Salvador
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