[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20241028073529.1383980-2-senozhatsky@chromium.org>
Date: Mon, 28 Oct 2024 16:34:57 +0900
From: Sergey Senozhatsky <senozhatsky@...omium.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Minchan Kim <minchan@...nel.org>,
linux-kernel@...r.kernel.org,
Sergey Senozhatsky <senozhatsky@...omium.org>,
Shin Kawamura <kawasin@...gle.com>
Subject: [PATCH 1/2] zram: clear IDLE flag after recompression
Recompression should clear ZRAM_IDLE flag on the entires
it has accessed, because otherwise some entries, specifically
those for which recompression has failed, become immediate
candidate entries for another post-processing (e.g. writeback).
Consider the following case:
- recompression marks entries IDLE every 4 hours and attempts
to recompress them
- some entries are incompressible, so we keep them intact and
hence preserve IDLE flag
- writeback marks entries IDLE every 8 hours and writebacks
IDLE entries, however we have IDLE entries left from
recompression, so writeback prematurely writebacks those
entries.
Reported-by: Shin Kawamura <kawasin@...gle.com>
Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
---
drivers/block/zram/zram_drv.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index e6d12e81241d..764c5b79b42b 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1864,6 +1864,13 @@ static int recompress_slot(struct zram *zram, u32 index, struct page *page,
if (ret)
return ret;
+ /*
+ * We touched this entry so mark it as non-IDLE. This makes sure that
+ * we don't preserve IDLE flag and don't incorrectly pick this entry
+ * for different post-processing type (e.g. writeback).
+ */
+ zram_clear_flag(zram, index, ZRAM_IDLE);
+
class_index_old = zs_lookup_class_index(zram->mem_pool, comp_len_old);
/*
* Iterate the secondary comp algorithms list (in order of priority)
--
2.47.0.163.g1226f6d8fa-goog
Powered by blists - more mailing lists