From cb325ddde5616219848ac0e100a781919a0ce55b Mon Sep 17 00:00:00 2001 From: "Maciej S. Szmigiero" Date: Tue, 22 Mar 2022 14:47:43 -0700 Subject: 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 Cc: Seth Jennings Cc: Dan Streetman Cc: Vitaly Wool Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/zswap.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) (limited to 'mm/zswap.c') 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) { -- cgit v1.2.3