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authorJeff Dike <jdike@addtoit.com>2005-09-03 18:57:36 -0400
committerLinus Torvalds <torvalds@evo.osdl.org>2005-09-05 03:06:22 -0400
commitc56004901fa5dcf55f92318f192ab3c0e87db2d1 (patch)
treeac53ded16ab9886ce05d4b2d424dfed80dce9e57 /arch/um/sys-i386
parent77fa5adcda6d686d2f45a2b55dcb9a03e7d33fa1 (diff)
[PATCH] uml: TLB operation batching
This adds VM op batching to skas0. Rather than having a context switch to and from the userspace stub for each address space change, we write a number of operations to the stub data page and invoke a different stub which loops over them and executes them all in one go. The operations are stored as [ system call number, arg1, arg2, ... ] tuples. The set is terminated by a system call number of 0. Single operations, i.e. page faults, are handled in the old way, since that is slightly more efficient. For a kernel build, a minority (~1/4) of the operations are part of a set. These sets averaged ~100 in length, so for this quarter, the context switching overhead is greatly reduced. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/um/sys-i386')
-rw-r--r--arch/um/sys-i386/stub.S17
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/um/sys-i386/stub.S b/arch/um/sys-i386/stub.S
index 2f2c70a8f043..a0f9506312d1 100644
--- a/arch/um/sys-i386/stub.S
+++ b/arch/um/sys-i386/stub.S
@@ -6,3 +6,20 @@ syscall_stub:
6 int $0x80 6 int $0x80
7 mov %eax, UML_CONFIG_STUB_DATA 7 mov %eax, UML_CONFIG_STUB_DATA
8 int3 8 int3
9
10 .globl batch_syscall_stub
11batch_syscall_stub:
12 mov $UML_CONFIG_STUB_DATA, %esp
13again: pop %eax
14 cmpl $0, %eax
15 jz done
16 pop %ebx
17 pop %ecx
18 pop %edx
19 pop %esi
20 pop %edi
21 pop %ebp
22 int $0x80
23 mov %eax, UML_CONFIG_STUB_DATA
24 jmp again
25done: int3