Messages in this thread | | | From | huang ying <> | Date | Tue, 16 Aug 2022 16:28:51 +0800 | Subject | Re: [PATCH v14 01/10] mm/demotion: Add support for explicit memory tiers |
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On Fri, Aug 12, 2022 at 1:58 PM Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> wrote:
[snip]
> diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h > new file mode 100644 > index 000000000000..bc7c1b799bef > --- /dev/null > +++ b/include/linux/memory-tiers.h > @@ -0,0 +1,15 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef _LINUX_MEMORY_TIERS_H > +#define _LINUX_MEMORY_TIERS_H > + > +/* > + * Each tier cover a abstrace distance chunk size of 128 > + */ > +#define MEMTIER_CHUNK_BITS 7 > +#define MEMTIER_CHUNK_SIZE (1 << MEMTIER_CHUNK_BITS) > +/* > + * Smaller abstract distance value imply faster(higher) memory tiers. > + */ > +#define MEMTIER_ADISTANCE_DRAM (4 * MEMTIER_CHUNK_SIZE)
This will make the abstract distance of DRAM the start of its memory tier. So that any memory type that is slightly slower than DRAM will be put in a lower memory tier. So I think it's better to put the DRAM at the middle of its memory tier by default. For example,
4 * MEMTIER_CHUNK_SIZE + MEMTIER_CHUNK_SIZE / 2
> + > +#endif /* _LINUX_MEMORY_TIERS_H */
[snip]
Best Regards, Huang, Ying
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