Re: [PATCH v21 18/19] mm/lru: introduce the relock_page_lruvec function

[Johannes Weiner]

On Fri, Nov 06, 2020 at 03:50:22PM +0800, Alex Shi wrote:
> From 6c142eb582e7d0dbf473572ad092eca07ab75221 Mon Sep 17 00:00:00 2001
> From: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
> Date: Tue, 26 May 2020 17:31:15 +0800
> Subject: [PATCH v21 18/19] mm/lru: introduce the relock_page_lruvec function
> 
> Use this new function to replace repeated same code, no func change.
> 
> When testing for relock we can avoid the need for RCU locking if we simply
> compare the page pgdat and memcg pointers versus those that the lruvec is
> holding. By doing this we can avoid the extra pointer walks and accesses of
> the memory cgroup.
> 
> In addition we can avoid the checks entirely if lruvec is currently NULL.
> 
> Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
> Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
> Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
> Cc: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
> Cc: Hugh Dickins <hughd@xxxxxxxxxx>
> Cc: Tejun Heo <tj@xxxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: cgroups@xxxxxxxxxxxxxxx
> Cc: linux-mm@xxxxxxxxx

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>