The patch titled
Subject: mm/vmalloc: fix performance regression caused by needless vmalloc_sync_all()
has been removed from the -mm tree. Its filename was
mm-vmalloc-fix-regression-caused-by-needless-vmalloc_sync_all.patch
This patch was dropped because an alternative patch was merged
------------------------------------------------------
From: Shile Zhang <shile.zhang@xxxxxxxxxxxxxxxxx>
Subject: mm/vmalloc: fix performance regression caused by needless vmalloc_sync_all()
vmalloc_sync_all() was put in the common path in __purge_vmap_area_lazy(),
for one sync issue only happened on X86_32 with PTI enabled. It is
needless for X86_64, which caused a big regression in UnixBench Shell8
testing on X86_64. Similar regression also reported by 0-day kernel test
robot in reaim benchmarking:
https://lists.01.org/hyperkitty/list/lkp@xxxxxxxxxxxx/thread/4D3JPPHBNOSPFK2KEPC6KGKS6J25AIDB/
Fix it by adding more conditions.
[akpm@xxxxxxxxxxxxxxxxxxxx: simplify config expression, use IS_ENABLED()]
[akpm@xxxxxxxxxxxxxxxxxxxx: build fix - go back to using an ifdef]
Link: http://lkml.kernel.org/r/20191113095530.228959-1-shile.zhang@xxxxxxxxxxxxxxxxx
Fixes: 3f8fd02b1bf1 ("mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy()")
Signed-off-by: Shile Zhang <shile.zhang@xxxxxxxxxxxxxxxxx>
Cc: Joerg Roedel <jroedel@xxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmalloc.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
--- a/mm/vmalloc.c~mm-vmalloc-fix-regression-caused-by-needless-vmalloc_sync_all
+++ a/mm/vmalloc.c
@@ -1255,11 +1255,17 @@ static bool __purge_vmap_area_lazy(unsig
if (unlikely(valist == NULL))
return false;
+#ifdef CONFIG_X86_PAE
/*
- * First make sure the mappings are removed from all page-tables
- * before they are freed.
+ * First make sure the mappings are removed from all pagetables before
+ * they are freed.
+ *
+ * This is only needed on x86-32 with !SHARED_KERNEL_PMD, which is the
+ * case on a PAE kernel with PTI enabled.
*/
- vmalloc_sync_all();
+ if (!SHARED_KERNEL_PMD && boot_cpu_has(X86_FEATURE_PTI))
+ vmalloc_sync_all();
+#endif
/*
* TODO: to calculate a flush range without looping.
_
Patches currently in -mm which might be from shile.zhang@xxxxxxxxxxxxxxxxx are
