linux-kernel - [PATCHv2] zram: further limit recompression threshold

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Date:   Thu, 15 Jun 2023 10:30:20 +0900
From:   Sergey Senozhatsky <senozhatsky@...omium.org>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Minchan Kim <minchan@...nel.org>
Cc:     Jens Axboe <axboe@...nel.dk>, linux-kernel@...r.kernel.org,
        linux-block@...r.kernel.org,
        Sergey Senozhatsky <senozhatsky@...omium.org>,
        Brian Geffon <bgeffon@...gle.com>
Subject: [PATCHv2] zram: further limit recompression threshold

Recompression threshold should be below huge-size-class watermark.
Any object larger than huge-size-class is a "huge object" and
occupies a whole physical page on the zsmalloc side, in other
words it's incompressible, as far as zsmalloc is concerned.

Suggested-by: Brian Geffon <bgeffon@...gle.com>
Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
---
 drivers/block/zram/zram_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 1867f378b319..5676e6dd5b16 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1753,7 +1753,7 @@ static ssize_t recompress_store(struct device *dev,
 		}
 	}
 
-	if (threshold >= PAGE_SIZE)
+	if (threshold >= huge_class_size)
 		return -EINVAL;
 
 	down_read(&zram->init_lock);
-- 
2.41.0.162.gfafddb0af9-goog