The patch titled
Subject: mm: compaction: optimize compact_memory to comply with the admin-guide
has been added to the -mm mm-unstable branch. Its filename is
mm-compaction-optimize-compact_memory-to-comply-with-the-admin-guide.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-compaction-optimize-compact_memory-to-comply-with-the-admin-guide.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Wen Yang <wenyang.linux@xxxxxxxxxxx>
Subject: mm: compaction: optimize compact_memory to comply with the admin-guide
Date: Tue, 25 Apr 2023 23:52:35 +0800
For the /proc/sys/vm/compact_memory file, the admin-guide states: When 1
is written to the file, all zones are compacted such that free memory is
available in contiguous blocks where possible. This can be important for
example in the allocation of huge pages although processes will also
directly compact memory as required
But it was not strictly followed, writing any value would cause all zones
to be compacted.
It has been slightly optimized to comply with the admin-guide. Enforce
the 1 on the unlikely chance that the sysctl handler is ever extended to
do something different.
Commit ef4984384172 ("mm/compaction: remove unused variable
sysctl_compact_memory") has also been optimized a bit here, as the
declaration in the external header file has been eliminated, and
sysctl_compact_memory also needs to be verified.
Link: https://lkml.kernel.org/r/tencent_DFF54DB2A60F3333F97D3F6B5441519B050A@xxxxxx
Signed-off-by: Wen Yang <wenyang.linux@xxxxxxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: William Lam <william.lam@xxxxxxxxxxxxx>
Cc: Pintu Kumar <pintu@xxxxxxxxxxxxxx>
Cc: Fu Wei <wefu@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
--- a/mm/compaction.c~mm-compaction-optimize-compact_memory-to-comply-with-the-admin-guide
+++ a/mm/compaction.c
@@ -1736,6 +1736,7 @@ static int sysctl_compact_unevictable_al
*/
static unsigned int __read_mostly sysctl_compaction_proactiveness = 20;
static int sysctl_extfrag_threshold = 500;
+static int sysctl_compact_memory;
static inline void
update_fast_start_pfn(struct compact_control *cc, unsigned long pfn)
@@ -2780,6 +2781,15 @@ static int compaction_proactiveness_sysc
static int sysctl_compaction_handler(struct ctl_table *table, int write,
void *buffer, size_t *length, loff_t *ppos)
{
+ int ret;
+
+ ret = proc_dointvec(table, write, buffer, length, ppos);
+ if (ret)
+ return ret;
+
+ if (sysctl_compact_memory != 1)
+ return -EINVAL;
+
if (write)
compact_nodes();
@@ -3095,7 +3105,7 @@ static int proc_dointvec_minmax_warn_RT_
static struct ctl_table vm_compaction[] = {
{
.procname = "compact_memory",
- .data = NULL,
+ .data = &sysctl_compact_memory,
.maxlen = sizeof(int),
.mode = 0200,
.proc_handler = sysctl_compaction_handler,
_
Patches currently in -mm which might be from wenyang.linux@xxxxxxxxxxx are
mm-compaction-optimize-compact_memory-to-comply-with-the-admin-guide.patch
