linux-kernel - [PATCHv4 5/9] zram: huge size watermark cannot be global

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Date:   Mon, 31 Oct 2022 14:41:04 +0900
From:   Sergey Senozhatsky <senozhatsky@...omium.org>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Minchan Kim <minchan@...nel.org>
Cc:     Nitin Gupta <ngupta@...are.org>, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: [PATCHv4 5/9] zram: huge size watermark cannot be global

ZRAM will pass pool specific limit on number of pages
per-zspages which will affect pool's characteristics.
Namely huge size class watermark value. Move huge_class_size
to struct zram, because this value now can be unique to the
pool (zram device).

Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
---
 drivers/block/zram/zram_drv.c | 13 +++----------
 drivers/block/zram/zram_drv.h |  5 +++++
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index fd31beb6491a..90b0c66bbd5b 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -50,12 +50,6 @@ static const char *default_comp_algs[ZRAM_MAX_ZCOMPS] = {
 
 /* Module params (documentation at end) */
 static unsigned int num_devices = 1;
-/*
- * Pages that compress to sizes equals or greater than this are stored
- * uncompressed in memory.
- */
-static size_t huge_class_size;
-
 static const struct block_device_operations zram_devops;
 
 static void zram_free_page(struct zram *zram, size_t index);
@@ -1259,8 +1253,7 @@ static bool zram_meta_alloc(struct zram *zram, u64 disksize)
 		return false;
 	}
 
-	if (!huge_class_size)
-		huge_class_size = zs_huge_class_size(zram->mem_pool);
+	zram->huge_class_size = zs_huge_class_size(zram->mem_pool);
 	return true;
 }
 
@@ -1488,7 +1481,7 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
 		return ret;
 	}
 
-	if (comp_len >= huge_class_size)
+	if (comp_len >= zram->huge_class_size)
 		comp_len = PAGE_SIZE;
 	/*
 	 * handle allocation has 2 paths:
@@ -1665,7 +1658,7 @@ static int zram_recompress(struct zram *zram, u32 index, struct page *page,
 	 * in a way that will save us memory. Mark the object so that we
 	 * don't attempt to re-compress it again (RECOMP_SKIP).
 	 */
-	if (comp_len_next >= huge_class_size ||
+	if (comp_len_next >= zram->huge_class_size ||
 	    comp_len_next >= comp_len_prev ||
 	    class_index_next >= class_index_prev ||
 	    ret) {
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 09b9ceb5dfa3..9d6fcfdf7aa7 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -120,6 +120,11 @@ struct zram {
 	 */
 	u64 disksize;	/* bytes */
 	const char *comp_algs[ZRAM_MAX_ZCOMPS];
+	/*
+	 * Pages that compress to sizes equal or greater than this are stored
+	 * uncompressed in memory.
+	 */
+	size_t huge_class_size;
 	/*
 	 * zram is claimed so open request will be failed
 	 */
-- 
2.38.1.273.g43a17bfeac-goog