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[PATCH] uml: TLB operation batching

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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>
This commit is contained in:
Jeff Dike
2005-09-03 15:57:36 -07:00
committed by Linus Torvalds
parent 77fa5adcda
commit c56004901f
8 changed files with 273 additions and 166 deletions
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23
arch/um/kernel/skas/tlb.c
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@@ -18,7 +18,8 @@
#include "os.h"
#include "tlb.h"
static void do_ops(union mm_context *mmu, struct host_vm_op *ops, int last)
static void *do_ops(union mm_context *mmu, struct host_vm_op *ops, int last,
int finished, void *flush)
{
struct host_vm_op *op;
int i;
@@ -27,24 +28,28 @@ static void do_ops(union mm_context *mmu, struct host_vm_op *ops, int last)
op = &ops[i];
switch(op->type){
case MMAP:
map(&mmu->skas.id, op->u.mmap.addr, op->u.mmap.len,
op->u.mmap.r, op->u.mmap.w, op->u.mmap.x,
op->u.mmap.fd, op->u.mmap.offset);
flush = map(&mmu->skas.id, op->u.mmap.addr,
op->u.mmap.len, op->u.mmap.r, op->u.mmap.w,
op->u.mmap.x, op->u.mmap.fd,
op->u.mmap.offset, finished, flush);
break;
case MUNMAP:
unmap(&mmu->skas.id, (void *) op->u.munmap.addr,
op->u.munmap.len);
flush = unmap(&mmu->skas.id, (void *) op->u.munmap.addr,
op->u.munmap.len, finished, flush);
break;
case MPROTECT:
protect(&mmu->skas.id, op->u.mprotect.addr,
op->u.mprotect.len, op->u.mprotect.r,
op->u.mprotect.w, op->u.mprotect.x);
flush = protect(&mmu->skas.id, op->u.mprotect.addr,
op->u.mprotect.len, op->u.mprotect.r,
op->u.mprotect.w, op->u.mprotect.x,
finished, flush);
break;
default:
printk("Unknown op type %d in do_ops\n", op->type);
break;
}
}
return flush;
}
extern int proc_mm;