From: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
To: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: dyoung@redhat.com, bhe@redhat.com, vgoyal@redhat.com,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] kexec: allocate buffer in top-down, if specified, correctly
Date: Fri, 28 Apr 2017 16:33:34 -0300 [thread overview]
Message-ID: <2404647.dtAsaUPUyE@morokweng> (raw)
In-Reply-To: <20170428005135.GA3963@fireball>
Am Freitag, 28. April 2017, 09:51:39 BRT schrieb AKASHI Takahiro:
> On Thu, Apr 27, 2017 at 07:00:04PM -0300, Thiago Jung Bauermann wrote:
> > Hello,
> >
> > Am Mittwoch, 26. April 2017, 17:22:09 BRT schrieb AKASHI Takahiro:
> > > The current kexec_locate_mem_hole(kbuf.top_down == 1) stops searching at
> > > the first memory region that has enough space for requested size even if
> > > some of higher regions may also have.
> >
> > kexec_locate_mem_hole expects arch_kexec_walk_mem to walk memory from top
> > to bottom if top_down is true. That is what powerpc's version does.
>
> Ah, I haven't noticed that, but x86 doesn't have arch_kexec_walk_mem and
> how can it work for x86?
Looking at v4.9's kexec_add_buffer, the logic has been this way before I
factored kexec_locate_mem_hole out of it. So x86 has been behaving this way
for a while.
> > Isn't it possible to walk resources from top to bottom?
>
> Yes, it will be, but it seems to me that such a behavior is not intuitive
> and even confusing if it doesn't come with explicit explanation.
Yes, I should have put a comment pointing out that assumption.
--
Thiago Jung Bauermann
IBM Linux Technology Center
next prev parent reply other threads:[~2017-04-28 19:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-26 8:22 [PATCH] kexec: allocate buffer in top-down, if specified, correctly AKASHI Takahiro
2017-04-27 22:00 ` Thiago Jung Bauermann
2017-04-28 0:51 ` AKASHI Takahiro
2017-04-28 5:19 ` Dave Young
2017-04-28 5:23 ` Dave Young
2017-04-28 19:33 ` Thiago Jung Bauermann [this message]
2017-04-28 4:46 ` Dave Young
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