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Date:   Sun, 25 Sep 2022 13:00:49 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     wangyong <yongw.pur@gmail.com>
Cc:     jaewon31.kim@samsung.com, 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>
Subject: Re: [PATCH v2 stable-4.19 1/3] mm/page_alloc: use ac->high_zoneidx
 for classzone_idx
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 <20220925103529.13716-1-yongw.pur@gmail.com>
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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?

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?

thanks,

greg k-h