From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexey Romanov <avromanov@sberdevices.ru>,
minchan@kernel.org, senozhatsky@chromium.org, ngupta@vflare.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel@sberdevices.ru
Subject: Re: [PATCH v1] zram: add size class equals check into recompression
Date: Tue, 25 Oct 2022 10:21:02 +0900 [thread overview]
Message-ID: <Y1c5/mSBc+ctWH6v@google.com> (raw)
In-Reply-To: <20221024135909.e351a2dde4eea521f359a04b@linux-foundation.org>
On (22/10/24 13:59), Andrew Morton wrote:
> > It makes no sense for us to recompress the object if it will
> > be in the same size class. We anyway don't get any memory gain.
> > But, at the same time, we get a CPU time overhead when inserting
> > this object into zspage and decompressing it afterwards.
> >
>
> Dumb question: is it ever possible for compression to result in an
> increase in size?
That's a good question. Re-compressed object can be bigger than the
original compressed one, but this should already be taken care of.
We do
if (comp_len_next >= huge_class_size ||
comp_len_next >= comp_len_prev ||
This checks whether recompressed object is above huge-size watermark and
whether recompressed size is larger than the original size.
next prev parent reply other threads:[~2022-10-25 1:21 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-24 12:09 Alexey Romanov
2022-10-24 20:59 ` Andrew Morton
2022-10-25 1:21 ` Sergey Senozhatsky [this message]
2022-10-25 1:53 ` Sergey Senozhatsky
2022-10-25 2:04 ` Sergey Senozhatsky
2022-10-25 9:49 ` Aleksey Romanov
2022-10-25 9:54 ` Sergey Senozhatsky
2022-10-25 10:08 ` Sergey Senozhatsky
2022-10-25 11:55 ` Aleksey Romanov
2022-10-25 12:38 ` Sergey Senozhatsky
2022-10-25 12:56 ` Aleksey Romanov
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