From: Michal Hocko <mhocko@kernel.org>
To: Wei Yang <richard.weiyang@gmail.com>
Cc: 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 13:48:17 +0100 [thread overview]
Message-ID: <20161221124816.GJ31118@dhcp22.suse.cz> (raw)
In-Reply-To: <20161221124320.GA23096@vultr.guest>
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.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2016-12-21 12:48 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 [this message]
2016-12-21 13:15 ` Wei Yang
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=20161221124816.GJ31118@dhcp22.suse.cz \
--to=mhocko@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=richard.weiyang@gmail.com \
--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).