From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id 6E7E06B025F for ; Fri, 21 Jul 2017 06:01:54 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id w72so11265907pfa.7 for ; Fri, 21 Jul 2017 03:01:54 -0700 (PDT) Received: from mail-pg0-x242.google.com (mail-pg0-x242.google.com. [2607:f8b0:400e:c05::242]) by mx.google.com with ESMTPS id w64si1302935pfk.356.2017.07.21.03.01.53 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 21 Jul 2017 03:01:53 -0700 (PDT) Received: by mail-pg0-x242.google.com with SMTP id s4so5045198pgr.5 for ; Fri, 21 Jul 2017 03:01:53 -0700 (PDT) From: Zhaoyang Huang Subject: [PATCH v1] mm/vmalloc: add a node corresponding to cached_hole_size Date: Fri, 21 Jul 2017 18:01:41 +0800 Message-Id: <1500631301-17444-1-git-send-email-zhaoyang.huang@spreadtrum.com> Sender: owner-linux-mm@kvack.org List-ID: To: zhaoyang.huang@spreadtrum.com, Andrew Morton , Michal Hocko , Ingo Molnar , zijun_hu , Vlastimil Babka , Thomas Garnier , "Kirill A. Shutemov" , Andrey Ryabinin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, zijun_hu@zoho.com we just record the cached_hole_size now, which will be used when the criteria meet both of 'free_vmap_cache == NULL' and 'size < cached_hole_size'. However, under above scenario, the search will start from the rb_root and then find the node which just in front of the cached hole. free_vmap_cache miss: vmap_area_root / \ _next U / (T1) cached_hole_node / ... (T2) / first vmap_area_list->first->......->cached_hole_node->cached_hole_node.list.next |-------(T3)-------| | <<< cached_hole_size >>> | vmap_area_list->......->cached_hole_node->cached_hole_node.list.next | <<< cached_hole_size >>> | The time cost to search the node now is T = T1 + T2 + T3. The commit add a cached_hole_node here to record the one just in front of the cached_hole_size, which can help to avoid walking the rb tree and the list and make the T = 0; Signed-off-by: Zhaoyang Huang --- mm/vmalloc.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 8698c1c..4e76e7f 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -336,6 +336,7 @@ unsigned long vmalloc_to_pfn(const void *vmalloc_addr) /* The vmap cache globals are protected by vmap_area_lock */ static struct rb_node *free_vmap_cache; +static struct vmap_area *cached_hole_node; static unsigned long cached_hole_size; static unsigned long cached_vstart; static unsigned long cached_align; @@ -444,6 +445,12 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, size < cached_hole_size || vstart < cached_vstart || align < cached_align) { + /*if we have a cached node, just use it*/ + if ((size < cached_hole_size) && cached_hole_node != NULL) { + addr = ALIGN(cached_hole_node->va_end, align); + cached_hole_node = NULL; + goto found; + } nocache: cached_hole_size = 0; free_vmap_cache = NULL; @@ -487,8 +494,13 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, /* from the starting point, walk areas until a suitable hole is found */ while (addr + size > first->va_start && addr + size <= vend) { - if (addr + cached_hole_size < first->va_start) + if (addr + cached_hole_size < first->va_start) { cached_hole_size = first->va_start - addr; + /*record the node corresponding to the hole*/ + cached_hole_node = (first->list.prev == + &vmap_area_list) ? + NULL : list_prev_entry(first, list); + } addr = ALIGN(first->va_end, align); if (addr + size < addr) goto overflow; @@ -571,10 +583,17 @@ static void __free_vmap_area(struct vmap_area *va) } } } + if (va == cached_hole_node) { + /*cached node is freed, the hole get bigger*/ + if (cached_hole_node->list.prev != &vmap_area_list) + cached_hole_node = list_prev_entry(cached_hole_node, + list); + else + cached_hole_node = NULL; + } rb_erase(&va->rb_node, &vmap_area_root); RB_CLEAR_NODE(&va->rb_node); list_del_rcu(&va->list); - /* * Track the highest possible candidate for pcpu area * allocation. Areas outside of vmalloc area can be returned -- 1.9.1 -- 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