linux-kernel - Re: [PATCH v4 2/4] mm/sparsemem: Defer the ms->section_mem

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 7 Jun 2018 15:47:05 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     Baoquan He <bhe@...hat.com>, linux-kernel@...r.kernel.org,
        akpm@...ux-foundation.org, pagupta@...hat.com
Cc:     linux-mm@...ck.org, kirill.shutemov@...ux.intel.com
Subject: Re: [PATCH v4 2/4] mm/sparsemem: Defer the ms->section_mem_map
 clearing

On 05/21/2018 03:15 AM, Baoquan He wrote:
> In sparse_init(), if CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER=y, system
> will allocate one continuous memory chunk for mem maps on one node and
> populate the relevant page tables to map memory section one by one. If
> fail to populate for a certain mem section, print warning and its
> ->section_mem_map will be cleared to cancel the marking of being present.
> Like this, the number of mem sections marked as present could become
> less during sparse_init() execution.
> 
> Here just defer the ms->section_mem_map clearing if failed to populate
> its page tables until the last for_each_present_section_nr() loop. This
> is in preparation for later optimizing the mem map allocation.
> 
> Signed-off-by: Baoquan He <bhe@...hat.com>

Acked-By: Dave Hansen <dave.hansen@...el.com>