linux-kernel - Re: [PATCH] mm: Add Kcompressd for accelerated memory compression

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Message-ID: <CAKEwX=MsP6LGjMRNyaHnO5MkE_ne-u-cKLbGfVQcSR-ALoxBwA@mail.gmail.com>
Date: Thu, 1 May 2025 08:12:48 -0700
From: Nhat Pham <nphamcs@...il.com>
To: Johannes Weiner <hannes@...xchg.org>
Cc: Qun-Wei Lin <qun-wei.lin@...iatek.com>, Andrew Morton <akpm@...ux-foundation.org>, 
	Mike Rapoport <rppt@...nel.org>, Matthias Brugger <matthias.bgg@...il.com>, 
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, 
	Sergey Senozhatsky <senozhatsky@...omium.org>, Minchan Kim <minchan@...nel.org>, linux-mm@...ck.org, 
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-mediatek@...ts.infradead.org, Casper Li <casper.li@...iatek.com>, 
	Chinwen Chang <chinwen.chang@...iatek.com>, Andrew Yang <andrew.yang@...iatek.com>, 
	James Hsu <james.hsu@...iatek.com>, Barry Song <21cnbao@...il.com>
Subject: Re: [PATCH] mm: Add Kcompressd for accelerated memory compression

On Thu, May 1, 2025 at 7:02 AM Johannes Weiner <hannes@...xchg.org> wrote:
>
>
> The way you implemented this adds time-and-space overhead even on
> systems that don't have any sort of swap compression enabled.
>
> That seems unnecessary. There is an existing method for asynchronous
> writeback, and pageout() is naturally fully set up to handle this.
>
> IMO the better way to do this is to make zswap_store() (and
> zram_bio_write()?) asynchronous. Make those functions queue the work
> and wake the compression daemon, and then have the daemon call
> folio_end_writeback() / bio_endio() when it's done with it.

+1.