UBUNTU: SAUCE: mm/page_alloc.c: disable memory reclaim watermark boosting by default

BugLink: https://bugs.launchpad.net/bugs/1861359
High watermark boosting can cause large swap activity under certain
memory intensive workloads, making the system very unresponsive (screen
does not refresh, keyboard not responding, etc.).

Disable this feature by default to prevent potential large swap
activity.

Signed-off-by: Sultan Alsawaf <sultan.alsawaf@canonical.com>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 519a60d5b6f7d5017c788ced10c9fcca6637dd65..c846052bc62d5d76a33d8946cbcd97902fdabbdb 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -321,20 +321,7 @@ compound_page_dtor * const compound_page_dtors[NR_COMPOUND_DTORS] = {
 
 int min_free_kbytes = 1024;
 int user_min_free_kbytes = -1;
-#ifdef CONFIG_DISCONTIGMEM
-/*
- * DiscontigMem defines memory ranges as separate pg_data_t even if the ranges
- * are not on separate NUMA nodes. Functionally this works but with
- * watermark_boost_factor, it can reclaim prematurely as the ranges can be
- * quite small. By default, do not boost watermarks on discontigmem as in
- * many cases very high-order allocations like THP are likely to be
- * unsupported and the premature reclaim offsets the advantage of long-term
- * fragmentation avoidance.
- */
 int watermark_boost_factor __read_mostly;
-#else
-int watermark_boost_factor __read_mostly = 15000;
-#endif
 int watermark_scale_factor = 10;
 
 static unsigned long nr_kernel_pages __initdata;