From: Johannes Berg <johannes.berg@intel.com>
Date: Mon, 15 Mar 2021 22:38:04 +0000 (+0100)
Subject: um: implement flush_cache_vmap/flush_cache_vunmap
X-Git-Tag: v5.14-rc1~34^2~5
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=80f849bf541ef9b633a9c08ac208f9c9afd14eb9;p=thirdparty%2Fkernel%2Flinux.git

um: implement flush_cache_vmap/flush_cache_vunmap

vmalloc() heavy workloads in UML are extremely slow, due to
flushing the entire kernel VM space (flush_tlb_kernel_vm())
on the first segfault.

Implement flush_cache_vmap() to avoid that, and while at it
also add flush_cache_vunmap() since it's trivial.

This speeds up my vmalloc() heavy test of copying files out
from /sys/kernel/debug/gcov/ by 30x (from 30s to 1s.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
---

diff --git a/arch/um/include/asm/cacheflush.h b/arch/um/include/asm/cacheflush.h
new file mode 100644
index 0000000000000..4c9858cd36ecb
--- /dev/null
+++ b/arch/um/include/asm/cacheflush.h
@@ -0,0 +1,9 @@
+#ifndef __UM_ASM_CACHEFLUSH_H
+#define __UM_ASM_CACHEFLUSH_H
+
+#include <asm/tlbflush.h>
+#define flush_cache_vmap flush_tlb_kernel_range
+#define flush_cache_vunmap flush_tlb_kernel_range
+
+#include <asm-generic/cacheflush.h>
+#endif /* __UM_ASM_CACHEFLUSH_H */
diff --git a/arch/um/include/asm/tlb.h b/arch/um/include/asm/tlb.h
index ff9c62828962c..0422467bda5ba 100644
--- a/arch/um/include/asm/tlb.h
+++ b/arch/um/include/asm/tlb.h
@@ -5,7 +5,7 @@
 #include <linux/mm.h>
 
 #include <asm/tlbflush.h>
-#include <asm-generic/cacheflush.h>
+#include <asm/cacheflush.h>
 #include <asm-generic/tlb.h>
 
 #endif