Re: [PATCH] mm: extend zero pages to same element pages for zram

From: Sergey Senozhatsky
Date: Sun Jan 22 2017 - 00:01:59 EST


On (01/22/17 10:58), zhouxianrong wrote:
> 1. memset is just set a int value but i want to set a long value.

ah... ok. because you union it with the handle.

> 2. using clear_page rather than memset MAYBE due to in arm64 arch
> it is a 64-bytes operations.

clear_page() basically does memset(), which is quite well optimized.
except for arm64, yes.


> 6.6.4. Data Cache Zero
>
> The ARMv8-A architecture introduces a Data Cache Zero by Virtual Address (DC ZVA) instruction. This enables a block of 64
> bytes in memory, aligned to 64 bytes in size, to be set to zero. If the DC ZVA instruction misses in the cache, it clears main
> memory, without causing an L1 or L2 cache allocation.
>
> but i only consider the arm64 arch, other archs need to be reviewed.

thaks for the reply.

-ss