From: Dave Hansen <dave.hansen@intel.com>
To: Baoquan He <bhe@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
ben.widawsky@intel.com, alex.shi@linux.alibaba.com,
dwagner@suse.de, tobin@kernel.org, cl@linux.com,
akpm@linux-foundation.org, stable@kernel.org
Subject: Re: [PATCH] mm/vmscan: restore zone_reclaim_mode ABI
Date: Mon, 29 Jun 2020 16:37:37 -0700 [thread overview]
Message-ID: <791c47ad-5a6b-1f1b-c34b-d8bbf7722957@intel.com> (raw)
In-Reply-To: <20200629233043.GK3346@MiWiFi-R3L-srv>
On 6/29/20 4:30 PM, Baoquan He wrote:
>> The only way I can plausibly think of "cleaning up" the RECLAIM_ZONE bit
>> would be to raise our confidence that it is truly unused. That takes
>> time, and probably a warning if we see it being set. If we don't run
>> into anybody setting it or depending on it being set in a few years, we
>> can remove it.
> So adding the old bit back for compatibility looks good, thanks.
>
> Then we have to be very careful when adding and reviewing new
> interface introducing, should not leave one which might be used
> in the future.
>
> In fact, RECLAIM_ZONE is not completely useless. At least, when the old
> bit 0 is set, it may enter into node_reclaim() in get_page_from_freelist(),
> that makes it like a switch.
>
> get_page_from_freelist {
>
> ...
> if (node_reclaim_mode == 0 ||
> !zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
> continue;
> ...
> }
Oh, that's a very good point. There are a couple of those around. Let
me circle back and update the documentation and the variable name. I'll
send out another version.
next prev parent reply other threads:[~2020-06-29 23:37 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-26 0:34 [PATCH] mm/vmscan: restore zone_reclaim_mode ABI Dave Hansen
2020-06-26 7:59 ` Daniel Wagner
2020-06-26 13:53 ` Dave Hansen
2020-06-29 7:13 ` Daniel Wagner
2020-06-29 14:36 ` Dave Hansen
2020-06-29 15:53 ` Daniel Wagner
2020-06-29 16:05 ` Dave Hansen
[not found] ` <20200626192426.GA4329@lca.pw>
2020-06-26 21:24 ` Dave Hansen
2020-06-29 6:52 ` Baoquan He
2020-06-29 14:27 ` Dave Hansen
2020-06-29 23:30 ` Baoquan He
2020-06-29 23:37 ` Dave Hansen [this message]
2020-07-01 2:47 ` Andrew Morton
2020-07-01 15:27 ` Dave Hansen
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