From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-gg0-f175.google.com (mail-gg0-f175.google.com [209.85.161.175]) by kanga.kvack.org (Postfix) with ESMTP id 160276B0036 for ; Thu, 2 Jan 2014 17:03:59 -0500 (EST) Received: by mail-gg0-f175.google.com with SMTP id u2so2859888ggn.20 for ; Thu, 02 Jan 2014 14:03:58 -0800 (PST) Received: from mail-gg0-x231.google.com (mail-gg0-x231.google.com [2607:f8b0:4002:c02::231]) by mx.google.com with ESMTPS id q66si35613yhm.54.2014.01.02.14.03.56 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 02 Jan 2014 14:03:58 -0800 (PST) Received: by mail-gg0-f177.google.com with SMTP id 4so2913451ggm.36 for ; Thu, 02 Jan 2014 14:03:56 -0800 (PST) Date: Thu, 2 Jan 2014 14:03:53 -0800 (PST) From: David Rientjes Subject: Re: [PATCH] mm/memblock: use WARN_ONCE when MAX_NUMNODES passed as input parameter In-Reply-To: <52C1635D.9070703@ti.com> Message-ID: References: <1387578536-18280-1-git-send-email-santosh.shilimkar@ti.com> <52C1635D.9070703@ti.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Grygorii Strashko Cc: Santosh Shilimkar , akpm@linux-foundation.org, tj@kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Yinghai Lu On Mon, 30 Dec 2013, Grygorii Strashko wrote: > > > diff --git a/mm/memblock.c b/mm/memblock.c > > > index 71b11d9..6af873a 100644 > > > --- a/mm/memblock.c > > > +++ b/mm/memblock.c > > > @@ -707,11 +707,9 @@ void __init_memblock __next_free_mem_range(u64 *idx, > > > int nid, > > > struct memblock_type *rsv = &memblock.reserved; > > > int mi = *idx & 0xffffffff; > > > int ri = *idx >> 32; > > > - bool check_node = (nid != NUMA_NO_NODE) && (nid != MAX_NUMNODES); > > > > > > - if (nid == MAX_NUMNODES) > > > - pr_warn_once("%s: Usage of MAX_NUMNODES is depricated. Use > > > NUMA_NO_NODE instead\n", > > > - __func__); > > > + if (WARN_ONCE(nid == MAX_NUMNODES, "Usage of MAX_NUMNODES is > > > deprecated. Use NUMA_NO_NODE instead\n")) > > > + nid = NUMA_NO_NODE; > > > > > > for ( ; mi < mem->cnt; mi++) { > > > struct memblock_region *m = &mem->regions[mi]; > > > > Um, why do this at runtime? This is only used for > > for_each_free_mem_range(), which is used rarely in x86 and memblock-only > > code. I'm struggling to understand why we can't deterministically fix the > > callers if this condition is possible. > > > > > Unfortunately, It's not so simple as from first look :( > We've modified __next_free_mem_range_x() functions which are part of > Memblock APIs (like memblock_alloc_xxx()) and Nobootmem APIs. > These APIs are used as directly as indirectly (as part of callbacks from other > MM modules like Sparse), as result, it's not trivial to identify all places > where MAX_NUMNODES will be used as input parameter. > These functions are only used for for_each_free_mem_range() and for_each_free_mem_range_reverse(). I can very easily find which callers are passing MAX_NUMNODES deterministically. NACK to doing this at runtime. -- 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