From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id 0F08C6B0007 for ; Fri, 13 Jul 2018 09:17:53 -0400 (EDT) Received: by mail-wm0-f69.google.com with SMTP id f13-v6so6048263wmb.4 for ; Fri, 13 Jul 2018 06:17:53 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id u19-v6sor1683690wmc.34.2018.07.13.06.17.50 for (Google Transport Security); Fri, 13 Jul 2018 06:17:50 -0700 (PDT) Date: Fri, 13 Jul 2018 15:17:49 +0200 From: Oscar Salvador Subject: Re: [PATCH v5 1/5] mm/sparse: abstract sparse buffer allocations Message-ID: <20180713131749.GA16765@techadventures.net> References: <20180712203730.8703-1-pasha.tatashin@oracle.com> <20180712203730.8703-2-pasha.tatashin@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180712203730.8703-2-pasha.tatashin@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: To: Pavel Tatashin Cc: steven.sistare@oracle.com, daniel.m.jordan@oracle.com, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, mhocko@suse.com, linux-mm@kvack.org, dan.j.williams@intel.com, jack@suse.cz, jglisse@redhat.com, jrdr.linux@gmail.com, bhe@redhat.com, gregkh@linuxfoundation.org, vbabka@suse.cz, richard.weiyang@gmail.com, dave.hansen@intel.com, rientjes@google.com, mingo@kernel.org, abdhalee@linux.vnet.ibm.com, mpe@ellerman.id.au On Thu, Jul 12, 2018 at 04:37:26PM -0400, Pavel Tatashin wrote: > +static void *sparsemap_buf __meminitdata; > +static void *sparsemap_buf_end __meminitdata; > + > +void __init sparse_buffer_init(unsigned long size, int nid) > +{ > + BUG_ON(sparsemap_buf); Why do we need a BUG_ON() here? Looking at the code I cannot really see how we can end up with sparsemap_buf being NULL. Is it just for over-protection? > + sparsemap_buf = > + memblock_virt_alloc_try_nid_raw(size, PAGE_SIZE, > + __pa(MAX_DMA_ADDRESS), > + BOOTMEM_ALLOC_ACCESSIBLE, nid); In your previous version, you didn't pass a required alignment when setting up sparsemap_buf. size is already PMD_SIZE aligned, do we need to align it also to PAGE_SIZE? Thanks -- Oscar Salvador SUSE L3