From:   SeongJae Park <sj@kernel.org>
To:     SeongJae Park <sj@kernel.org>
Cc:     Baolin Wang <baolin.wang@linux.alibaba.com>,
        akpm@linux-foundation.org, torvalds@linux-foundation.org,
        hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev,
        shakeelb@google.com, muchun.song@linux.dev,
        naoya.horiguchi@nec.com, linmiaohe@huawei.com, david@redhat.com,
        osalvador@suse.de, mike.kravetz@oracle.com, willy@infradead.org,
        damon@lists.linux.dev, cgroups@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 3/4] mm: hugetlb: change to return bool for isolate_hugetlb()
Date:   Tue, 14 Feb 2023 18:07:08 +0000
Message-Id: <20230214180708.71645-1-sj@kernel.org>
In-Reply-To: <20230214180324.71585-1-sj@kernel.org>
References: 
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On Tue, 14 Feb 2023 18:03:24 +0000 SeongJae Park <sj@kernel.org> wrote:

> On Tue, 14 Feb 2023 21:59:31 +0800 Baolin Wang <baolin.wang@linux.alibaba.com> wrote:
> 
> > Now the isolate_hugetlb() only returns 0 or -EBUSY, and most users did not
> > care about the negative value, thus we can convert the isolate_hugetlb()
> > to return a boolean value to make code more clear when checking the
> > hugetlb isolation state. Moreover converts 2 users which will consider
> > the negative value returned by isolate_hugetlb().
> > 
> > No functional changes intended.
> > 
> > Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> > ---
> >  include/linux/hugetlb.h |  6 +++---
> >  mm/hugetlb.c            | 12 ++++++++----
> >  mm/memory-failure.c     |  2 +-
> >  mm/mempolicy.c          |  2 +-
> >  mm/migrate.c            |  2 +-
> >  5 files changed, 14 insertions(+), 10 deletions(-)
> > 
> > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> > index df6dd624ccfe..5f5e4177b2e0 100644
[...]
> > diff --git a/mm/migrate.c b/mm/migrate.c
> > index 53010a142e7f..c5136fa48638 100644
> > --- a/mm/migrate.c
> > +++ b/mm/migrate.c
> > @@ -2128,7 +2128,7 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr,
> >  		if (PageHead(page)) {
> >  			err = isolate_hugetlb(page_folio(page), pagelist);
> >  			if (!err)
> > -				err = 1;
> > +				err = -EBUSY;
> 
> Again, I think this is confusing.  'err' is 'bool', not 'int'.

I mean, 'err' is not 'bool' but 'int', sorry.  See? This confuses me ;)


Thanks,
SJ

> 
> 
> Thanks,
> SJ
> 
> >  		}
> >  	} else {
> >  		struct page *head;
> > -- 
> > 2.27.0
> >