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Date:   Sat, 30 Jan 2021 17:10:37 -0800 (PST)
From:   David Rientjes <rientjes@google.com>
To:     Dave Hansen <dave.hansen@linux.intel.com>
cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        ben.widawsky@intel.com, cl@linux.com, alex.shi@linux.alibaba.com,
        tobin@kernel.org, akpm@linux-foundation.org, ying.huang@intel.com,
        dan.j.williams@intel.com, cai@lca.pw, dwagner@suse.de,
        osalvador@suse.de
Subject: Re: [RFC][PATCH 03/13] mm/vmscan: replace implicit RECLAIM_ZONE
 checks with explicit checks
In-Reply-To: <20210126003417.72B4BCFB@viggo.jf.intel.com>
Message-ID: <4ea95a1a-33b0-eb15-98d8-79c81dc8a37@google.com>
References: <20210126003411.2AC51464@viggo.jf.intel.com> <20210126003417.72B4BCFB@viggo.jf.intel.com>
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On Mon, 25 Jan 2021, Dave Hansen wrote:

> 
> From: Dave Hansen <dave.hansen@linux.intel.com>
> 
> RECLAIM_ZONE was assumed to be unused because it was never explicitly
> used in the kernel.  However, there were a number of places where it
> was checked implicitly by checking 'node_reclaim_mode' for a zero
> value.
> 
> These zero checks are not great because it is not obvious what a zero
> mode *means* in the code.  Replace them with a helper which makes it
> more obvious: node_reclaim_enabled().
> 
> This helper also provides a handy place to explicitly check the
> RECLAIM_ZONE bit itself.  Check it explicitly there to make it more
> obvious where the bit can affect behavior.
> 
> This should have no functional impact.
> 
> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
> Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
> Acked-by: Christoph Lameter <cl@linux.com>
> Cc: Alex Shi <alex.shi@linux.alibaba.com>
> Cc: "Tobin C. Harding" <tobin@kernel.org>
> Cc: Christoph Lameter <cl@linux.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Huang Ying <ying.huang@intel.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Qian Cai <cai@lca.pw>
> Cc: Daniel Wagner <dwagner@suse.de>
> Cc: osalvador <osalvador@suse.de>

Acked-by: David Rientjes <rientjes@google.com>