From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751056AbdEaA4G (ORCPT ); Tue, 30 May 2017 20:56:06 -0400 Received: from mga06.intel.com ([134.134.136.31]:44362 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750824AbdEaA4F (ORCPT ); Tue, 30 May 2017 20:56:05 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.38,420,1491289200"; d="scan'208";a="1136366593" Subject: Re: [RFC PATCH] vmalloc: show more detail info in vmallocinfo for clarify To: Yisheng Xie , akpm@linux-foundation.org, mhocko@suse.com, zijun_hu@htc.com, mingo@kernel.org, thgarnie@google.com, kirill.shutemov@linux.intel.com, aryabinin@virtuozzo.com, chris@chris-wilson.co.uk References: <1495262861-37649-1-git-send-email-xieyisheng1@huawei.com> Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, guohanjun@huawei.com From: Tim Chen Message-ID: <857f6900-8a28-6ac6-64ac-d4867ef01ee5@linux.intel.com> Date: Tue, 30 May 2017 17:56:03 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <1495262861-37649-1-git-send-email-xieyisheng1@huawei.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/19/2017 11:47 PM, Yisheng Xie wrote: > When ioremap a 67112960 bytes vm_area with the vmallocinfo: > [..] > 0xec79b000-0xec7fa000 389120 ftl_add_mtd+0x4d0/0x754 pages=94 vmalloc > 0xec800000-0xecbe1000 4067328 kbox_proc_mem_write+0x104/0x1c4 phys=8b520000 ioremap > > we get result: > 0xf1000000-0xf5001000 67112960 devm_ioremap+0x38/0x7c phys=40000000 ioremap > > For the align for ioremap must be less than '1 << IOREMAP_MAX_ORDER': > if (flags & VM_IOREMAP) > align = 1ul << clamp_t(int, get_count_order_long(size), > PAGE_SHIFT, IOREMAP_MAX_ORDER); > > So it makes idiot like me a litter puzzle why jump the vm_area from > 0xec800000-0xecbe1000 to 0xf1000000-0xf5001000, and leave > 0xed000000-0xf1000000 as a big hole. > > This is to show all of vm_area, including which is freeing but still in > vmap_area_list, to make it more clear about why we will get > 0xf1000000-0xf5001000 int the above case. And we will get the > vmallocinfo like: > [..] > 0xec79b000-0xec7fa000 389120 ftl_add_mtd+0x4d0/0x754 pages=94 vmalloc > 0xec800000-0xecbe1000 4067328 kbox_proc_mem_write+0x104/0x1c4 phys=8b520000 ioremap > [..] > 0xece7c000-0xece7e000 8192 freeing vm_area > 0xece7e000-0xece83000 20480 vm_map_ram > 0xf0099000-0xf00aa000 69632 vm_map_ram > 0xf1000000-0xf5001000 67112960 devm_ioremap+0x38/0x7c phys=40000000 ioremap > after apply this patch. > > Signed-off-by: Yisheng Xie > --- > mm/vmalloc.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index b52aeed..dbb24fc 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -314,6 +314,7 @@ unsigned long vmalloc_to_pfn(const void *vmalloc_addr) > > /*** Global kva allocator ***/ > > +#define VM_LAZY_FREE 0x02 > #define VM_VM_AREA 0x04 > > static DEFINE_SPINLOCK(vmap_area_lock); > @@ -1486,6 +1487,7 @@ struct vm_struct *remove_vm_area(const void *addr) > spin_lock(&vmap_area_lock); > va->vm = NULL; > va->flags &= ~VM_VM_AREA; > + va->flags |= VM_LAZY_FREE; > spin_unlock(&vmap_area_lock); > > vmap_debug_free_range(va->va_start, va->va_end); > @@ -2684,8 +2686,14 @@ static int s_show(struct seq_file *m, void *p) > * s_show can encounter race with remove_vm_area, !VM_VM_AREA on > * behalf of vmap area is being tear down or vm_map_ram allocation. > */ > - if (!(va->flags & VM_VM_AREA)) > + if (!(va->flags & VM_VM_AREA)) { > + seq_printf(m, "0x%pK-0x%pK %7ld %s\n", > + (void *)va->va_start, (void *)va->va_end, > + va->va_end - va->va_start, > + va->flags & VM_LAZY_FREE ? "freeing vm_area" : "vm_map_ram"); Will be clearer to say "unpurged vm_area" instead of "freeing vm_area". Thanks. Tim