Re: [PATCH] Revert "mm/vunmap: add cond_resched() in vunmap_pmd_range"

From: Sergey Senozhatsky
Date: Tue Nov 17 2020 - 21:07:40 EST


On (20/11/17 12:29), Minchan Kim wrote:
> Yub, I remeber the discussion.
> https://lore.kernel.org/linux-mm/20200416203736.GB50092@xxxxxxxxxx/
>
> I wanted to remove it but 30% gain made me think again before
> deciding to drop it.
> Since it continue to make problems and Linux is approaching to
> deprecate the 32bit machines, I think it would be better to drop it
> rather than inventing weird workaround.
>
> Ccing Tony since omap2plus have used it by default for just in case.
>
> From fc1b17a120991fd86b9e1153ab22d0b0bdadd8d0 Mon Sep 17 00:00:00 2001
> From: Minchan Kim <minchan@xxxxxxxxxx>
> Date: Tue, 17 Nov 2020 11:58:51 -0800
> Subject: [PATCH] mm/zsmalloc.c: drop ZSMALLOC_PGTABLE_MAPPING
>
> Even though this option showed some amount improvement(e.g., 30%)
> in some arm32 platforms, it has been headache to maintain since it
> have abused APIs[1](e.g., unmap_kernel_range in atomic context).
>
> Since we are approaching to deprecate 32bit machines and already made
> the config option available for only builtin build since v5.8, lastly
> it has been not default option in zsmalloc, it's time to drop the
> option for better maintainance.
>
> [1] http://lore.kernel.org/linux-mm/20201105170249.387069-1-minchan@xxxxxxxxxx
>
> Cc: Tony Lindgren <tony@xxxxxxxxxxx>
> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Fixes: e47110e90584 ("mm/vunmap: add cond_resched() in vunmap_pmd_range")
> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>

Looks good to me.

Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>

-ss