From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f70.google.com (mail-pg0-f70.google.com [74.125.83.70]) by kanga.kvack.org (Postfix) with ESMTP id 18C4C6B0397 for ; Thu, 13 Apr 2017 16:02:21 -0400 (EDT) Received: by mail-pg0-f70.google.com with SMTP id u195so38742724pgb.1 for ; Thu, 13 Apr 2017 13:02:21 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id s128si24675096pgc.85.2017.04.13.13.02.20 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 13 Apr 2017 13:02:20 -0700 (PDT) Date: Thu, 13 Apr 2017 13:02:17 -0700 From: Andrew Morton Subject: Re: [PATCH v9 3/5] mm: function to offer a page block on the free list Message-Id: <20170413130217.2316b0394192d8677f5ddbdf@linux-foundation.org> In-Reply-To: <1492076108-117229-4-git-send-email-wei.w.wang@intel.com> References: <1492076108-117229-1-git-send-email-wei.w.wang@intel.com> <1492076108-117229-4-git-send-email-wei.w.wang@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Wei Wang Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, linux-mm@kvack.org, mst@redhat.com, david@redhat.com, dave.hansen@intel.com, cornelia.huck@de.ibm.com, mgorman@techsingularity.net, aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com, liliang.opensource@gmail.com On Thu, 13 Apr 2017 17:35:06 +0800 Wei Wang wrote: > Add a function to find a page block on the free list specified by the > caller. Pages from the page block may be used immediately after the > function returns. The caller is responsible for detecting or preventing > the use of such pages. > > ... > > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -4498,6 +4498,93 @@ void show_free_areas(unsigned int filter) > show_swap_cache_info(); > } > > +/** > + * Heuristically get a page block in the system that is unused. > + * It is possible that pages from the page block are used immediately after > + * inquire_unused_page_block() returns. It is the caller's responsibility > + * to either detect or prevent the use of such pages. > + * > + * The free list to check: zone->free_area[order].free_list[migratetype]. > + * > + * If the caller supplied page block (i.e. **page) is on the free list, offer > + * the next page block on the list to the caller. Otherwise, offer the first > + * page block on the list. > + * > + * Return 0 when a page block is found on the caller specified free list. > + */ > +int inquire_unused_page_block(struct zone *zone, unsigned int order, > + unsigned int migratetype, struct page **page) > +{ Perhaps we can wrap this in the appropriate ifdef so the kernels which won't be using virtio-balloon don't carry the added overhead. -- 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