From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wj0-f198.google.com (mail-wj0-f198.google.com [209.85.210.198]) by kanga.kvack.org (Postfix) with ESMTP id A0FD26B0069 for ; Mon, 28 Nov 2016 09:17:33 -0500 (EST) Received: by mail-wj0-f198.google.com with SMTP id j10so20865281wjb.3 for ; Mon, 28 Nov 2016 06:17:33 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id b124si26010459wmg.77.2016.11.28.06.17.32 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 28 Nov 2016 06:17:32 -0800 (PST) Subject: Re: [PATCH V2 fix 5/6] mm: hugetlb: add a new function to allocate a new gigantic page References: <1479107259-2011-6-git-send-email-shijie.huang@arm.com> <1479279304-31379-1-git-send-email-shijie.huang@arm.com> From: Vlastimil Babka Message-ID: Date: Mon, 28 Nov 2016 15:17:28 +0100 MIME-Version: 1.0 In-Reply-To: <1479279304-31379-1-git-send-email-shijie.huang@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Huang Shijie , akpm@linux-foundation.org, catalin.marinas@arm.com Cc: n-horiguchi@ah.jp.nec.com, mhocko@suse.com, kirill.shutemov@linux.intel.com, aneesh.kumar@linux.vnet.ibm.com, gerald.schaefer@de.ibm.com, mike.kravetz@oracle.com, linux-mm@kvack.org, will.deacon@arm.com, steve.capper@arm.com, kaly.xin@arm.com, nd@arm.com, linux-arm-kernel@lists.infradead.org On 11/16/2016 07:55 AM, Huang Shijie wrote: > There are three ways we can allocate a new gigantic page: > > 1. When the NUMA is not enabled, use alloc_gigantic_page() to get > the gigantic page. > > 2. The NUMA is enabled, but the vma is NULL. > There is no memory policy we can refer to. > So create a @nodes_allowed, initialize it with init_nodemask_of_mempolicy() > or init_nodemask_of_node(). Then use alloc_fresh_gigantic_page() to get > the gigantic page. > > 3. The NUMA is enabled, and the vma is valid. > We can follow the memory policy of the @vma. > > Get @nodes_allowed by huge_nodemask(), and use alloc_fresh_gigantic_page() > to get the gigantic page. > > Signed-off-by: Huang Shijie > --- > Since the huge_nodemask() is changed, we have to change this function a little. > > --- > mm/hugetlb.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 63 insertions(+) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 6995087..c33bddc 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1502,6 +1502,69 @@ int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) > > /* > * There are 3 ways this can get called: > + * > + * 1. When the NUMA is not enabled, use alloc_gigantic_page() to get > + * the gigantic page. > + * > + * 2. The NUMA is enabled, but the vma is NULL. > + * Create a @nodes_allowed, and use alloc_fresh_gigantic_page() to get > + * the gigantic page. > + * > + * 3. The NUMA is enabled, and the vma is valid. > + * Use the @vma's memory policy. > + * Get @nodes_allowed by huge_nodemask(), and use alloc_fresh_gigantic_page() > + * to get the gigantic page. > + */ > +static struct page *__hugetlb_alloc_gigantic_page(struct hstate *h, > + struct vm_area_struct *vma, unsigned long addr, int nid) > +{ > + NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); What if the allocation fails and nodes_allowed is NULL? It might work fine now, but it's rather fragile, so I'd rather see an explicit check. BTW same thing applies to __nr_hugepages_store_common(). > + struct page *page = NULL; > + > + /* Not NUMA */ > + if (!IS_ENABLED(CONFIG_NUMA)) { > + if (nid == NUMA_NO_NODE) > + nid = numa_mem_id(); > + > + page = alloc_gigantic_page(nid, huge_page_order(h)); > + if (page) > + prep_compound_gigantic_page(page, huge_page_order(h)); > + > + NODEMASK_FREE(nodes_allowed); > + return page; > + } > + > + /* NUMA && !vma */ > + if (!vma) { > + if (nid == NUMA_NO_NODE) { > + if (!init_nodemask_of_mempolicy(nodes_allowed)) { > + NODEMASK_FREE(nodes_allowed); > + nodes_allowed = &node_states[N_MEMORY]; > + } > + } else if (nodes_allowed) { > + init_nodemask_of_node(nodes_allowed, nid); > + } else { > + nodes_allowed = &node_states[N_MEMORY]; > + } > + > + page = alloc_fresh_gigantic_page(h, nodes_allowed, true); > + > + if (nodes_allowed != &node_states[N_MEMORY]) > + NODEMASK_FREE(nodes_allowed); > + > + return page; > + } > + > + /* NUMA && vma */ > + if (huge_nodemask(vma, addr, nodes_allowed)) > + page = alloc_fresh_gigantic_page(h, nodes_allowed, true); > + > + NODEMASK_FREE(nodes_allowed); > + return page; > +} > + > +/* > + * There are 3 ways this can get called: > * 1. With vma+addr: we use the VMA's memory policy > * 2. With !vma, but nid=NUMA_NO_NODE: We try to allocate a huge > * page from any node, and let the buddy allocator itself figure > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org