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Fri, 16 Apr 2021 09:49:22 +0000 (UTC) Date: Fri, 16 Apr 2021 17:49:20 +0800 From: Baoquan He To: Oscar Salvador Cc: Andrew Morton , Mike Kravetz , Vlastimil Babka , David Hildenbrand , Michal Hocko , Muchun Song , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Michal Hocko Subject: Re: [PATCH v9 5/7] mm: Make alloc_contig_range handle free hugetlb pages Message-ID: <20210416094920.GA8560@MiWiFi-R3L-srv> References: <20210416070023.4742-1-osalvador@suse.de> <20210416070023.4742-6-osalvador@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210416070023.4742-6-osalvador@suse.de> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 511765001528 X-Stat-Signature: gpi3zexgrwjogtcnzftbuur9jb6n6nzf Received-SPF: none (redhat.com>: No applicable sender policy available) receiver=imf01; identity=mailfrom; envelope-from=""; helo=us-smtp-delivery-124.mimecast.com; client-ip=216.205.24.124 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1618566571-341035 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 04/16/21 at 09:00am, Oscar Salvador wrote: ... > +/* > + * alloc_and_dissolve_huge_page - Allocate a new page and dissolve the old one > + * @h: struct hstate old page belongs to > + * @old_page: Old page to dissolve > + * Returns 0 on success, otherwise negated error. > + */ > +static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page) > +{ > + gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE; > + int nid = page_to_nid(old_page); > + struct page *new_page; > + int ret = 0; > + > + /* > + * Before dissolving the page, we need to allocate a new one for the > + * pool to remain stable. Using alloc_buddy_huge_page() allows us to > + * not having to deal with prep_new_page() and avoids dealing of any ~ prep_new_huge_page() ? > + * counters. This simplifies and let us do the whole thing under the > + * lock. > + */ > + new_page = alloc_buddy_huge_page(h, gfp_mask, nid, NULL, NULL); > + if (!new_page) > + return -ENOMEM; > + > +retry: > + spin_lock_irq(&hugetlb_lock); ...