linux-kernel - Re: [EXTERNAL] Re: [RFC PATCH V2 2/10] mm: expose is_mem_section

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20200120141433.GI18451@dhcp22.suse.cz>
Date:   Mon, 20 Jan 2020 15:14:33 +0100
From:   Michal Hocko <mhocko@...nel.org>
To:     Tianyu Lan <Tianyu.Lan@...rosoft.com>
Cc:     David Hildenbrand <david@...hat.com>,
        "lantianyu1986@...il.com" <lantianyu1986@...il.com>,
        KY Srinivasan <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        "sashal@...nel.org" <sashal@...nel.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        Michael Kelley <mikelley@...rosoft.com>,
        "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        vkuznets <vkuznets@...hat.com>,
        "eric.devolder@...cle.com" <eric.devolder@...cle.com>,
        "vbabka@...e.cz" <vbabka@...e.cz>,
        "osalvador@...e.de" <osalvador@...e.de>,
        Pasha Tatashin <Pavel.Tatashin@...rosoft.com>,
        "rppt@...ux.ibm.com" <rppt@...ux.ibm.com>
Subject: Re: [EXTERNAL] Re: [RFC PATCH V2 2/10] mm: expose
 is_mem_section_removable() symbol

On Fri 17-01-20 16:35:03, Tianyu Lan wrote:
[...]
> > Could you describe your usecase in more details please?
> 
> Hyper-V sends hot-remove request message which just contains requested
> page number but not provide detail range. So Hyper-V driver needs to search
> suitable memory block in system memory to return back to host if there is no
> memory hot-add before. So I used the is_mem_section_removable() do such check.

As David described, you would be much better of by using
alloc_contig_range to find a memory that would be suitable for
hotremoving without any races.
-- 
Michal Hocko
SUSE Labs