Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Sergey Senozhatsky <senozhatsky@chromium.org>
To:     Andrew Morton <akpm@linux-foundation.org>,
        Minchan Kim <minchan@kernel.org>
Cc:     Jens Axboe <axboe@kernel.dk>, linux-kernel@vger.kernel.org,
        linux-block@vger.kernel.org,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Brian Geffon <bgeffon@google.com>
Subject: [PATCHv2] zram: further limit recompression threshold
Date:   Thu, 15 Jun 2023 10:30:20 +0900
Message-ID: <20230615013122.3564479-1-senozhatsky@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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@google.com>
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.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