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From:   yong w <yongw.pur@gmail.com>
Date:   Sun, 25 Sep 2022 22:32:32 +0800
Message-ID: <CAOH5QeBiSEe03KNge9voJ-HjKbNLDoeY2PfKC7HE7F6z-92d7A@mail.gmail.com>
Subject: Re: [PATCH v2 stable-4.19 1/3] mm/page_alloc: use ac->high_zoneidx
 for classzone_idx
To:     Greg KH <gregkh@linuxfoundation.org>, jaewon31.kim@samsung.com
Cc:     linux-kernel@vger.kernel.org, mhocko@kernel.org,
        stable@vger.kernel.org, wang.yong12@zte.com.cn,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Minchan Kim <minchan@kernel.org>,
        Mel Gorman <mgorman@techsingularity.net>,
        Linus Torvalds <torvalds@linux-foundation.org>
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Greg KH <gregkh@linuxfoundation.org> =E4=BA=8E2022=E5=B9=B49=E6=9C=8825=E6=
=97=A5=E5=91=A8=E6=97=A5 19:00=E5=86=99=E9=81=93=EF=BC=9A
>
> On Sun, Sep 25, 2022 at 03:35:27AM -0700, wangyong wrote:
> > From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> >
> > [ backport of commit 3334a45eb9e2bb040c880ef65e1d72357a0a008b ]
>
> This is from 5.8.  What about the 5.4.y kernel?  Why would someone
> upgrading from 4.19.y to 5.4.y suffer a regression here?
>
I encountered this problem on 4.19, but I haven't encountered it on 5.4.
However, this should be a common problem, so 5.4 may also need to be
merged.

Hello, Joonsoo, what do you think?

> And why wouldn't someone who has this issue just not use 5.10.y instead?
> What prevents someone from moving off of 4.19.y at this point in time?
>
This is a solution, but upgrading the kernel version requires time and over=
head,
so use the patch is the most effective way, if there is.

Thanks.
> thanks,
>
> greg k-h