Re: [PATCHv3 0/2] mm/memblock: reuse memblock bottom-up allocation style

From: Baoquan He <bhe@redhat.com>
To: Pingfan Liu <kernelfans@gmail.com>
Cc: linux-acpi@vger.kernel.org, linux-mm@kvack.org,
	kexec@lists.infradead.org, Tang Chen <tangchen@cn.fujitsu.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <lenb@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mike Rapoport <rppt@linux.vnet.ibm.com>,
	Michal Hocko <mhocko@suse.com>, Jonathan Corbet <corbet@lwn.net>,
	Yaowei Bai <baiyaowei@cmss.chinamobile.com>,
	Pavel Tatashin <pasha.tatashin@oracle.com>,
	Nicholas Piggin <npiggin@gmail.com>,
	Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
	Daniel Vacek <neelx@redhat.com>,
	Mathieu Malaterre <malat@debian.org>,
	Stefan Agner <stefan@agner.ch>, Dave Young <dyoung@redhat.com>,
	yinghai@kernel.org, vgoyal@redhat.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCHv3 0/2] mm/memblock: reuse memblock bottom-up allocation style
Date: Fri, 28 Dec 2018 11:39:40 +0800	[thread overview]
Message-ID: <20181228033940.GB1990@MiWiFi-R3L-srv> (raw)
In-Reply-To: <1545966002-3075-1-git-send-email-kernelfans@gmail.com>

On 12/28/18 at 11:00am, Pingfan Liu wrote:
> The bottom-up allocation style is introduced to cope with movable_node,
> where the limit inferior of allocation starts from kernel's end, due to
> lack of knowledge of memory hotplug info at this early time.
> Beside this original aim, 'kexec -c' prefers to reuse this style to alloc mem

Wondering what is 'kexec -c'.

> at lower address, since if the reserved region is beyond 4G, then it requires
> extra mem (default is 16M) for swiotlb. But at this time hotplug info has been

The default is 256M, not sure if we are talking about the same thing.

low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);

> got, the limit inferior can be extend to 0, which is done by this series
> 
> Cc: Tang Chen <tangchen@cn.fujitsu.com>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: Len Brown <lenb@kernel.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
> Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> Cc: Daniel Vacek <neelx@redhat.com>
> Cc: Mathieu Malaterre <malat@debian.org>
> Cc: Stefan Agner <stefan@agner.ch>
> Cc: Dave Young <dyoung@redhat.com>
> Cc: Baoquan He <bhe@redhat.com>
> Cc: yinghai@kernel.org,
> Cc: vgoyal@redhat.com
> Cc: linux-kernel@vger.kernel.org
> 
> Pingfan Liu (2):
>   mm/memblock: extend the limit inferior of bottom-up after parsing
>     hotplug attr
>   x86/kdump: bugfix, make the behavior of crashkernel=X consistent with
>     kaslr
> 
>  arch/x86/kernel/setup.c  |  9 +++++---
>  drivers/acpi/numa.c      |  4 ++++
>  include/linux/memblock.h |  1 +
>  mm/memblock.c            | 58 +++++++++++++++++++++++++++++-------------------
>  4 files changed, 46 insertions(+), 26 deletions(-)
> 
> -- 
> 2.7.4
> 