From: Dan Streetman <ddstreet@ieee.org>
To: Minchan Kim <minchan@kernel.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Nitin Gupta <ngupta@vflare.org>,
Seth Jennings <sjennings@variantweb.net>,
Andrew Morton <akpm@linux-foundation.org>,
Dan Streetman <ddstreet@ieee.org>
Subject: [PATCH 09/10] zsmalloc: add zs_shrink()
Date: Thu, 11 Sep 2014 16:54:00 -0400 [thread overview]
Message-ID: <1410468841-320-10-git-send-email-ddstreet@ieee.org> (raw)
In-Reply-To: <1410468841-320-1-git-send-email-ddstreet@ieee.org>
Add function zs_shrink() to implement zs_pool shrinking. This allows
the pool owner to reduce the size of the zs_pool by one zspage, which
contains one or more struct pages. Once the zs_pool is shrunk, the
freed pages are available for system use.
This is used by zswap to limit its total system memory usage to a
user-defined amount, while attempting to keep the most recently stored
pages compressed in memory, and the oldest (or older) pages are evicted
from the zsmalloc zs_pool and written out to swap disk.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
---
include/linux/zsmalloc.h | 1 +
mm/zsmalloc.c | 35 +++++++++++++++++++++++++++++++++++
2 files changed, 36 insertions(+)
diff --git a/include/linux/zsmalloc.h b/include/linux/zsmalloc.h
index 2c341d4..07fe84d 100644
--- a/include/linux/zsmalloc.h
+++ b/include/linux/zsmalloc.h
@@ -45,6 +45,7 @@ void zs_destroy_pool(struct zs_pool *pool);
unsigned long zs_malloc(struct zs_pool *pool, size_t size);
void zs_free(struct zs_pool *pool, unsigned long obj);
+int zs_shrink(struct zs_pool *pool);
void *zs_map_object(struct zs_pool *pool, unsigned long handle,
enum zs_mapmode mm);
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 60fd23e..f769c21 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1296,6 +1296,41 @@ void zs_free(struct zs_pool *pool, unsigned long obj)
EXPORT_SYMBOL_GPL(zs_free);
/**
+ * zs_shrink - Shrink the pool
+ * @pool: pool to shrink
+ *
+ * The pool will be shrunk by one zspage, which is some
+ * number of pages in size. On success, the number of freed
+ * pages is returned. On failure, the error is returned.
+ */
+int zs_shrink(struct zs_pool *pool)
+{
+ struct size_class *class;
+ enum fullness_group fullness;
+ struct page *page;
+ int class_idx, ret;
+
+ if (!pool->ops || !pool->ops->evict)
+ return -EINVAL;
+
+ /* if a page is found, the class is locked */
+ page = find_lru_zspage(pool);
+ if (!page)
+ return -ENOENT;
+
+ get_zspage_mapping(page, &class_idx, &fullness);
+ class = &pool->size_class[class_idx];
+
+ /* reclaim_zspage unlocks the class lock */
+ ret = reclaim_zspage(pool, page);
+ if (ret)
+ return ret;
+
+ return class->pages_per_zspage;
+}
+EXPORT_SYMBOL_GPL(zs_shrink);
+
+/**
* zs_map_object - get address of allocated object from handle.
* @pool: pool from which the object was allocated
* @handle: handle returned from zs_malloc
--
1.8.3.1
next prev parent reply other threads:[~2014-09-11 20:55 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-11 20:53 [PATCH 00/10] implement zsmalloc shrinking Dan Streetman
2014-09-11 20:53 ` [PATCH 01/10] zsmalloc: fix init_zspage free obj linking Dan Streetman
2014-09-12 3:16 ` Seth Jennings
2014-09-12 4:59 ` Minchan Kim
2014-09-12 16:43 ` Dan Streetman
2014-09-14 23:24 ` Minchan Kim
2014-09-15 20:58 ` [PATCH] zsmalloc: simplify " Dan Streetman
2014-09-16 2:41 ` Minchan Kim
2014-09-11 20:53 ` [PATCH 02/10] zsmalloc: add fullness group list for ZS_FULL zspages Dan Streetman
2014-09-11 20:53 ` [PATCH 03/10] zsmalloc: always update lru ordering of each zspage Dan Streetman
2014-09-12 3:20 ` Seth Jennings
2014-09-11 20:53 ` [PATCH 04/10] zsmalloc: move zspage obj freeing to separate function Dan Streetman
2014-09-11 20:53 ` [PATCH 05/10] zsmalloc: add atomic index to find zspage to reclaim Dan Streetman
2014-09-11 20:53 ` [PATCH 06/10] zsmalloc: add zs_ops to zs_pool Dan Streetman
2014-09-11 20:53 ` [PATCH 07/10] zsmalloc: add obj_handle_is_free() Dan Streetman
2014-09-11 20:53 ` [PATCH 08/10] zsmalloc: add reclaim_zspage() Dan Streetman
2014-09-11 20:54 ` Dan Streetman [this message]
2014-09-11 20:54 ` [PATCH 10/10] zsmalloc: implement zs_zpool_shrink() with zs_shrink() Dan Streetman
2014-09-12 3:14 ` [PATCH 00/10] implement zsmalloc shrinking Seth Jennings
2014-09-12 5:46 ` Minchan Kim
2014-09-12 17:05 ` Dan Streetman
2014-09-15 0:00 ` Minchan Kim
2014-09-15 14:29 ` Dan Streetman
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