Re: [PATCH v7 0/6] Implement writeback for zsmalloc

From: Nhat Pham
Date: Fri Jan 06 2023 - 15:32:30 EST


On Mon, Jan 2, 2023 at 8:57 PM Thomas Weißschuh <thomas@xxxxxxxx> wrote:
>
> Hi,
>
> On Mon, Nov 28, 2022 at 11:16:09AM -0800, Nhat Pham wrote:
> > Unlike other zswap's allocators such as zbud or z3fold, zsmalloc
> > currently lacks the writeback mechanism. This means that when the zswap
> > pool is full, it will simply reject further allocations, and the pages
> > will be written directly to swap.
> >
> > This series of patches implements writeback for zsmalloc. When the zswap
> > pool becomes full, zsmalloc will attempt to evict all the compressed
> > objects in the least-recently used zspages.
>
> Then this part of Documentation/admin-guide/mm/zswap.rst should probably
> also be updated at some point:
>
> However, zsmalloc does not implement compressed page eviction, so
> once zswap fills it cannot evict the oldest page, it can only reject
> new pages.
>
> Thomas

Thanks for pointing this out, Thomas! I'll send a patch to update this.