From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f69.google.com (mail-pg0-f69.google.com [74.125.83.69]) by kanga.kvack.org (Postfix) with ESMTP id EBFC46B02FD for ; Wed, 16 Aug 2017 23:38:32 -0400 (EDT) Received: by mail-pg0-f69.google.com with SMTP id m133so54428781pga.2 for ; Wed, 16 Aug 2017 20:38:32 -0700 (PDT) Received: from mga01.intel.com (mga01.intel.com. [192.55.52.88]) by mx.google.com with ESMTPS id o19si1353342pgk.231.2017.08.16.20.38.31 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 16 Aug 2017 20:38:31 -0700 (PDT) From: Wei Wang Subject: [PATCH v14 4/5] mm: support reporting free page blocks Date: Thu, 17 Aug 2017 11:26:55 +0800 Message-Id: <1502940416-42944-5-git-send-email-wei.w.wang@intel.com> In-Reply-To: <1502940416-42944-1-git-send-email-wei.w.wang@intel.com> References: <1502940416-42944-1-git-send-email-wei.w.wang@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: 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, mhocko@kernel.org, akpm@linux-foundation.org, mawilcox@microsoft.com Cc: david@redhat.com, cornelia.huck@de.ibm.com, mgorman@techsingularity.net, aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com, willy@infradead.org, wei.w.wang@intel.com, liliang.opensource@gmail.com, yang.zhang.wz@gmail.com, quan.xu@aliyun.com This patch adds support to walk through the free page blocks in the system and report them via a callback function. Some page blocks may leave the free list after zone->lock is released, so it is the caller's responsibility to either detect or prevent the use of such pages. Signed-off-by: Wei Wang Signed-off-by: Liang Li Cc: Michal Hocko Cc: Michael S. Tsirkin --- include/linux/mm.h | 6 ++++++ mm/page_alloc.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 50 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 46b9ac5..cd29b9f 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1835,6 +1835,12 @@ extern void free_area_init_node(int nid, unsigned long * zones_size, unsigned long zone_start_pfn, unsigned long *zholes_size); extern void free_initmem(void); +extern void walk_free_mem_block(void *opaque1, + unsigned int min_order, + void (*visit)(void *opaque2, + unsigned long pfn, + unsigned long nr_pages)); + /* * Free reserved pages within range [PAGE_ALIGN(start), end & PAGE_MASK) * into the buddy system. The freed pages will be poisoned with pattern diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 6d00f74..a721a35 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4762,6 +4762,50 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) show_swap_cache_info(); } +/** + * walk_free_mem_block - Walk through the free page blocks in the system + * @opaque1: the context passed from the caller + * @min_order: the minimum order of free lists to check + * @visit: the callback function given by the caller + * + * The function is used to walk through the free page blocks in the system, + * and each free page block is reported to the caller via the @visit callback. + * Please note: + * 1) The function is used to report hints of free pages, so the caller should + * not use those reported pages after the callback returns. + * 2) The callback is invoked with the zone->lock being held, so it should not + * block and should finish as soon as possible. + */ +void walk_free_mem_block(void *opaque1, + unsigned int min_order, + void (*visit)(void *opaque2, + unsigned long pfn, + unsigned long nr_pages)) +{ + struct zone *zone; + struct page *page; + struct list_head *list; + unsigned int order; + enum migratetype mt; + unsigned long pfn, flags; + + for_each_populated_zone(zone) { + for (order = MAX_ORDER - 1; + order < MAX_ORDER && order >= min_order; order--) { + for (mt = 0; mt < MIGRATE_TYPES; mt++) { + spin_lock_irqsave(&zone->lock, flags); + list = &zone->free_area[order].free_list[mt]; + list_for_each_entry(page, list, lru) { + pfn = page_to_pfn(page); + visit(opaque1, pfn, 1 << order); + } + spin_unlock_irqrestore(&zone->lock, flags); + } + } + } +} +EXPORT_SYMBOL_GPL(walk_free_mem_block); + static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref) { zoneref->zone = zone; -- 2.7.4 -- 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