From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Hillf Danton <hdanton@sina.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
Brian Geffon <bgeffon@google.com>,
linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH v6 09/13] zram: split zcomp into separate R/W streams
Date: Wed, 21 Oct 2026 13:56:17 +0900 [thread overview]
Message-ID: <athFf0kXopUKh2-V@google.com> (raw)
In-Reply-To: <20261021042350.907-1-hdanton@sina.com>
On (26/10/21 12:23), Hillf Danton wrote:
> On Wed, 21 Oct 2026 11:42:19 +0900 Sergey Senozhatsky wrote:
> > Split struct zcomp_strm into separate compression (Write zcomp_cstrm)
> > and decompression (Read zcomp_dstrm) streams, and split zcomp_ops
> > context creation/destruction into create_cctx/destroy_cctx and
> > optional create_dctx/destroy_dctx callbacks.
> >
> > This decouples Read (decompression) and Write (compression) paths so
> > they no longer contend on the same per-CPU stream mutex (Writer vs
> > Reader priority inversion). Currently, a (low priority) Writer that
> > holds the stream mutex can be preempted by a (higher priority) Reader
> > on the same CPU, which then blocks on that mutex until the Writer gets
> > to run again and releases it, which can take a long time when there
> > are other runnable tasks on that CPU.
> >
> Given lock like mutex, priority inversion happens from Monday to Friday,
> but I wonder if you are inventing some wheels in 2026 if proxy excution
> works for you.
Reader-Writer split is a foundation for further improvements (like
singleton recompression stream and so on).
next prev parent reply other threads:[~2026-10-21 4:56 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-21 2:42 [PATCH v6 00/13] zram: redesign zcomp and rework backends Sergey Senozhatsky
2026-10-21 2:42 ` [PATCH v6 01/13] zram: prefix backends printk-s Sergey Senozhatsky
2026-10-21 2:42 ` [PATCH v6 02/13] zram: remove debugfs entry on init failure Sergey Senozhatsky
2026-10-21 2:42 ` [PATCH v6 03/13] zram: reset writeback state in zram_reset_device() Sergey Senozhatsky
2026-10-21 2:42 ` [PATCH v6 04/13] zram: zstd: do not allocate empty C/D-dictionaries Sergey Senozhatsky
2026-10-21 2:42 ` [PATCH v6 05/13] zram: lz4hc: pre-initialize dictionary stream in setup_params Sergey Senozhatsky
2026-10-21 2:42 ` [PATCH v6 06/13] zram: lz4: use LZ4_decompress_safe_usingDict() Sergey Senozhatsky
2026-10-21 2:42 ` [PATCH v6 07/13] zram: lz4hc: " Sergey Senozhatsky
2026-10-21 2:42 ` [PATCH v6 08/13] zram: zstd: do not use kvzalloc() for zstd allocations Sergey Senozhatsky
2026-10-21 2:42 ` [PATCH v6 09/13] zram: split zcomp into separate R/W streams Sergey Senozhatsky
2026-10-21 4:23 ` Hillf Danton
2026-10-21 4:56 ` Sergey Senozhatsky [this message]
2026-10-21 2:42 ` [PATCH v6 10/13] zram: introduce shared decompression streams Sergey Senozhatsky
2026-10-21 2:42 ` [PATCH v6 11/13] zram: allocate bounce buffer for spanning objects Sergey Senozhatsky
2026-10-21 2:42 ` [PATCH v6 12/13] zram: borrow idle decompression streams in exclusive mode Sergey Senozhatsky
2026-10-21 2:42 ` [PATCH v6 13/13] zram: use a singleton compression context for recompression Sergey Senozhatsky
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