From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
Yosry Ahmed <yosry.ahmed@linux.dev>,
Vitaly Wool <vitaly.wool@konsulko.se>,
linux-mm@kvack.org, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org, Nhat Pham <nphamcs@gmail.com>,
Shakeel Butt <shakeel.butt@linux.dev>,
Johannes Weiner <hannes@cmpxchg.org>,
Minchan Kim <minchan@kernel.org>,
Igor Belousov <igor.b@beldev.am>,
Herbert Xu <herbert@gondor.apana.org.au>
Subject: Re: [PATCH] mm/zblock: use vmalloc for page allocations
Date: Thu, 8 May 2025 15:17:56 +0900 [thread overview]
Message-ID: <at4djawky2n5d2nrxor62osid3mkaid4ttmlmc3xwsju2hstun@bos2kgakshpa> (raw)
In-Reply-To: <aBxIlUYEPojTopek@infradead.org>
On (25/05/07 23:00), Christoph Hellwig wrote:
> On Thu, May 08, 2025 at 02:58:14PM +0900, Sergey Senozhatsky wrote:
> > Oh, I didn't realize that zram was the only swap_slot_free_notify
> > user. zram already handles REQ_OP_DISCARD/REQ_OP_WRITE_ZEROES so
> > I guess only swap-cluster needs some work. Are there any
> > blockers/complications on the swap-cluster side?
>
> I think the reason it was added it was so that the discard can be
> done non-blocking with a spinlock held. Which seems a bit sketch
> when calling into a driver anyway..
swap_slot_free_notify is not guaranteed to free anything on the zram/zsmalloc
side. zram attempts to trylock entry and if it fails to acquire the ownership
swap_slot_free_notify for that entry becomes a .miss_free. So we just keep
stale data in zspage (potentially, preventing it from being released if that
was the last allocated object). I don't know if .miss_free happens often in
real life.
next prev parent reply other threads:[~2025-05-08 6:18 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-02 8:01 Vitaly Wool
2025-05-02 8:07 ` Igor Belousov
2025-05-03 18:46 ` Vitaly Wool
2025-05-04 5:02 ` Sergey Senozhatsky
2025-05-04 6:14 ` Sergey Senozhatsky
2025-05-05 14:08 ` Johannes Weiner
2025-05-06 2:13 ` Sergey Senozhatsky
2025-05-05 14:29 ` Johannes Weiner
2025-05-06 9:42 ` Uladzislau Rezki
2025-05-06 13:13 ` Yosry Ahmed
2025-05-06 13:27 ` Herbert Xu
2025-05-06 13:37 ` Christoph Hellwig
2025-05-07 5:57 ` Sergey Senozhatsky
2025-05-07 6:08 ` Sergey Senozhatsky
2025-05-07 6:14 ` Sergey Senozhatsky
2025-05-07 6:54 ` Christoph Hellwig
2025-05-08 5:58 ` Sergey Senozhatsky
2025-05-08 6:00 ` Christoph Hellwig
2025-05-08 6:17 ` Sergey Senozhatsky [this message]
2025-05-08 6:33 ` Sergey Senozhatsky
2025-05-07 8:50 ` Uladzislau Rezki
2025-05-08 6:07 ` Sergey Senozhatsky
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