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authorMaciej S. Szmigiero <maciej.szmigiero@oracle.com>2022-03-22 14:47:43 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-03-22 15:57:11 -0700
commitcb325ddde5616219848ac0e100a781919a0ce55b (patch)
tree677bd45c77d094f0ff54efb3dd5cf5681856fce2 /mm/zswap.c
parentbd55b0c2d64e84a75575f548a33a3dfecc135b65 (diff)
downloadlinux-cb325ddde5616219848ac0e100a781919a0ce55b.tar.bz2
mm/zswap.c: allow handling just same-value filled pages
Zswap has an ability to efficiently store same-value filled pages, which can be turned on and off using the "same_filled_pages_enabled" parameter. However, there is currently no way to enable just this (lightweight) functionality, while not making use of the whole compressed page storage machinery. Add a "non_same_filled_pages_enabled" parameter which allows disabling handling of pages that aren't same-value filled. This way zswap can be run in such lightweight same-value filled pages only mode. Link: https://lkml.kernel.org/r/7dbafa963e8bab43608189abbe2067f4b9287831.1641247624.git.maciej.szmigiero@oracle.com Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/zswap.c')
-rw-r--r--mm/zswap.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/mm/zswap.c b/mm/zswap.c
index cdf6950fcb2e..3efd8cae315e 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -120,11 +120,19 @@ static unsigned int zswap_accept_thr_percent = 90; /* of max pool size */
module_param_named(accept_threshold_percent, zswap_accept_thr_percent,
uint, 0644);
-/* Enable/disable handling same-value filled pages (enabled by default) */
+/*
+ * Enable/disable handling same-value filled pages (enabled by default).
+ * If disabled every page is considered non-same-value filled.
+ */
static bool zswap_same_filled_pages_enabled = true;
module_param_named(same_filled_pages_enabled, zswap_same_filled_pages_enabled,
bool, 0644);
+/* Enable/disable handling non-same-value filled pages (enabled by default) */
+static bool zswap_non_same_filled_pages_enabled = true;
+module_param_named(non_same_filled_pages_enabled, zswap_non_same_filled_pages_enabled,
+ bool, 0644);
+
/*********************************
* data structures
**********************************/
@@ -1147,6 +1155,11 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
kunmap_atomic(src);
}
+ if (!zswap_non_same_filled_pages_enabled) {
+ ret = -EINVAL;
+ goto freepage;
+ }
+
/* if entry is successfully added, it keeps the reference */
entry->pool = zswap_pool_current_get();
if (!entry->pool) {