linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Wei Yang <richard.weiyang@gmail.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>,
	trivial@kernel.org, akpm@linux-foundation.org,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2 1/2] mm/memblock.c: trivial code refine in memblock_is_region_memory()
Date: Wed, 21 Dec 2016 13:15:31 +0000	[thread overview]
Message-ID: <20161221131531.GC23096@vultr.guest> (raw)
In-Reply-To: <20161221124816.GJ31118@dhcp22.suse.cz>

On Wed, Dec 21, 2016 at 01:48:17PM +0100, Michal Hocko wrote:
>On Wed 21-12-16 12:43:20, Wei Yang wrote:
>> On Wed, Dec 21, 2016 at 08:48:09AM +0100, Michal Hocko wrote:
>> >On Tue 20-12-16 16:35:40, Wei Yang wrote:
>> >> On Mon, Dec 19, 2016 at 04:15:14PM +0100, Michal Hocko wrote:
>> >> >On Sun 18-12-16 14:47:49, Wei Yang wrote:
>> >> >> The base address is already guaranteed to be in the region by
>> >> >> memblock_search().
>> >> >
>> >> 
>> >> Hi, Michal
>> >> 
>> >> Nice to receive your comment.
>> >> 
>> >> >First of all the way how the check is removed is the worst possible...
>> >> >Apart from that it is really not clear to me why checking the base
>> >> >is not needed. You are mentioning memblock_search but what about other
>> >> >callers? adjust_range_page_size_mask e.g...
>> >> >
>> >> 
>> >> Hmm... the memblock_search() is called by memblock_is_region_memory(). Maybe I
>> >> paste the whole function here would clarify the change.
>> >> 
>> >> int __init_memblock memblock_is_region_memory(phys_addr_t base, phys_addr_t size)
>> >> {
>> >> 	int idx = memblock_search(&memblock.memory, base);
>> >> 	phys_addr_t end = base + memblock_cap_size(base, &size);
>> >> 
>> >> 	if (idx == -1)
>> >> 		return 0;
>> >> 	return memblock.memory.regions[idx].base <= base &&
>> >> 		(memblock.memory.regions[idx].base +
>> >> 		 memblock.memory.regions[idx].size) >= end;
>> >> }
>> >
>> >Ohh, my bad. I thought that memblock_search is calling
>> >memblock_is_region_memory. I didn't notice this is other way around.
>> >Then I agree that the check for the base is not needed and can be
>> >removed.
>> 
>> Thanks~ 
>> 
>> I would feel honored if you would like to add Acked-by :-)
>
>My Nack to the original patch still holds. If you want to remove the
>check then remove it rather than comment it out.

Got it, will send a new version.

>-- 
>Michal Hocko
>SUSE Labs

-- 
Wei Yang
Help you, Help me

  reply	other threads:[~2016-12-21 13:15 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-18 14:47 [PATCH V2 0/2] mm/memblock.c: fix potential bug and code refine Wei Yang
2016-12-18 14:47 ` [PATCH V2 1/2] mm/memblock.c: trivial code refine in memblock_is_region_memory() Wei Yang
2016-12-19 15:15   ` Michal Hocko
2016-12-20 16:35     ` Wei Yang
2016-12-21  7:48       ` Michal Hocko
2016-12-21 12:43         ` Wei Yang
2016-12-21 12:48           ` Michal Hocko
2016-12-21 13:15             ` Wei Yang [this message]
2016-12-18 14:47 ` [PATCH V2 2/2] mm/memblock.c: check return value of memblock_reserve() in memblock_virt_alloc_internal() Wei Yang
2016-12-19 15:21   ` Michal Hocko
2016-12-20 16:48     ` Wei Yang
2016-12-21  7:51       ` Michal Hocko
2016-12-21 13:13         ` Wei Yang
2016-12-21 13:22           ` Michal Hocko
2016-12-21 14:39             ` Wei Yang
2016-12-21 14:52               ` Michal Hocko

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20161221131531.GC23096@vultr.guest \
    --to=richard.weiyang@gmail.com \
    --cc=akpm@linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=trivial@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).