[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>
This commit is contained in:
Jeff Dike
committed by
Linus Torvalds
Linus Torvalds
parent
77fa5adcda
commit
c56004901f
@@ -15,12 +15,116 @@
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#include "mem_user.h"
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#include "os.h"
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static int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
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int r, int w, int x, struct host_vm_op *ops, int index,
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int last_filled, union mm_context *mmu, void **flush,
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void *(*do_ops)(union mm_context *, struct host_vm_op *,
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int, int, void *))
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{
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__u64 offset;
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struct host_vm_op *last;
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int fd;
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fd = phys_mapping(phys, &offset);
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if(index != -1){
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last = &ops[index];
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if((last->type == MMAP) &&
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(last->u.mmap.addr + last->u.mmap.len == virt) &&
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(last->u.mmap.r == r) && (last->u.mmap.w == w) &&
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(last->u.mmap.x == x) && (last->u.mmap.fd == fd) &&
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(last->u.mmap.offset + last->u.mmap.len == offset)){
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last->u.mmap.len += len;
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return index;
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}
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}
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if(index == last_filled){
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*flush = (*do_ops)(mmu, ops, last_filled, 0, *flush);
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index = -1;
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}
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ops[++index] = ((struct host_vm_op) { .type = MMAP,
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.u = { .mmap = {
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.addr = virt,
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.len = len,
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.r = r,
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.w = w,
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.x = x,
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.fd = fd,
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.offset = offset }
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} });
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return index;
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}
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static int add_munmap(unsigned long addr, unsigned long len,
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struct host_vm_op *ops, int index, int last_filled,
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union mm_context *mmu, void **flush,
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void *(*do_ops)(union mm_context *, struct host_vm_op *,
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int, int, void *))
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{
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struct host_vm_op *last;
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if(index != -1){
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last = &ops[index];
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if((last->type == MUNMAP) &&
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(last->u.munmap.addr + last->u.mmap.len == addr)){
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last->u.munmap.len += len;
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return index;
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}
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}
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if(index == last_filled){
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*flush = (*do_ops)(mmu, ops, last_filled, 0, *flush);
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index = -1;
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}
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ops[++index] = ((struct host_vm_op) { .type = MUNMAP,
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.u = { .munmap = {
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.addr = addr,
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.len = len } } });
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return index;
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}
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static int add_mprotect(unsigned long addr, unsigned long len, int r, int w,
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int x, struct host_vm_op *ops, int index,
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int last_filled, union mm_context *mmu, void **flush,
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void *(*do_ops)(union mm_context *,
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struct host_vm_op *, int, int, void *))
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{
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struct host_vm_op *last;
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if(index != -1){
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last = &ops[index];
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if((last->type == MPROTECT) &&
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(last->u.mprotect.addr + last->u.mprotect.len == addr) &&
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(last->u.mprotect.r == r) && (last->u.mprotect.w == w) &&
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(last->u.mprotect.x == x)){
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last->u.mprotect.len += len;
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return index;
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}
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}
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if(index == last_filled){
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*flush = (*do_ops)(mmu, ops, last_filled, 0, *flush);
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index = -1;
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}
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ops[++index] = ((struct host_vm_op) { .type = MPROTECT,
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.u = { .mprotect = {
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.addr = addr,
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.len = len,
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.r = r,
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.w = w,
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.x = x } } });
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return index;
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}
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#define ADD_ROUND(n, inc) (((n) + (inc)) & ~((inc) - 1))
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void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
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unsigned long end_addr, int force,
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void (*do_ops)(union mm_context *, struct host_vm_op *,
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int))
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void *(*do_ops)(union mm_context *, struct host_vm_op *,
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int, int, void *))
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{
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pgd_t *npgd;
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pud_t *npud;
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@@ -29,11 +133,13 @@ void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
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union mm_context *mmu = &mm->context;
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unsigned long addr, end;
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int r, w, x;
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struct host_vm_op ops[16];
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struct host_vm_op ops[1];
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void *flush = NULL;
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int op_index = -1, last_op = sizeof(ops) / sizeof(ops[0]) - 1;
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if(mm == NULL) return;
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ops[0].type = NONE;
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for(addr = start_addr; addr < end_addr;){
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npgd = pgd_offset(mm, addr);
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if(!pgd_present(*npgd)){
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@@ -43,7 +149,7 @@ void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
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if(force || pgd_newpage(*npgd)){
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op_index = add_munmap(addr, end - addr, ops,
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op_index, last_op, mmu,
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do_ops);
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&flush, do_ops);
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pgd_mkuptodate(*npgd);
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}
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addr = end;
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@@ -58,7 +164,7 @@ void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
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if(force || pud_newpage(*npud)){
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op_index = add_munmap(addr, end - addr, ops,
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op_index, last_op, mmu,
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do_ops);
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&flush, do_ops);
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pud_mkuptodate(*npud);
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}
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addr = end;
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@@ -73,7 +179,7 @@ void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
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if(force || pmd_newpage(*npmd)){
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op_index = add_munmap(addr, end - addr, ops,
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op_index, last_op, mmu,
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do_ops);
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&flush, do_ops);
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pmd_mkuptodate(*npmd);
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}
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addr = end;
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@@ -96,20 +202,20 @@ void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
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pte_val(*npte) & PAGE_MASK,
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PAGE_SIZE, r, w, x, ops,
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op_index, last_op, mmu,
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do_ops);
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&flush, do_ops);
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else op_index = add_munmap(addr, PAGE_SIZE, ops,
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op_index, last_op, mmu,
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do_ops);
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&flush, do_ops);
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}
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else if(pte_newprot(*npte))
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op_index = add_mprotect(addr, PAGE_SIZE, r, w, x, ops,
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op_index, last_op, mmu,
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do_ops);
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&flush, do_ops);
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*npte = pte_mkuptodate(*npte);
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addr += PAGE_SIZE;
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}
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(*do_ops)(mmu, ops, op_index);
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flush = (*do_ops)(mmu, ops, op_index, 1, flush);
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}
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int flush_tlb_kernel_range_common(unsigned long start, unsigned long end)
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@@ -226,106 +332,6 @@ pte_t *addr_pte(struct task_struct *task, unsigned long addr)
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return(pte_offset_map(pmd, addr));
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}
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int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
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int r, int w, int x, struct host_vm_op *ops, int index,
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int last_filled, union mm_context *mmu,
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void (*do_ops)(union mm_context *, struct host_vm_op *, int))
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{
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__u64 offset;
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struct host_vm_op *last;
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int fd;
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fd = phys_mapping(phys, &offset);
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if(index != -1){
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last = &ops[index];
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if((last->type == MMAP) &&
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(last->u.mmap.addr + last->u.mmap.len == virt) &&
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(last->u.mmap.r == r) && (last->u.mmap.w == w) &&
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(last->u.mmap.x == x) && (last->u.mmap.fd == fd) &&
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(last->u.mmap.offset + last->u.mmap.len == offset)){
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last->u.mmap.len += len;
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return(index);
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}
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}
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if(index == last_filled){
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(*do_ops)(mmu, ops, last_filled);
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index = -1;
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}
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ops[++index] = ((struct host_vm_op) { .type = MMAP,
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.u = { .mmap = {
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.addr = virt,
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.len = len,
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.r = r,
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.w = w,
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.x = x,
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.fd = fd,
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.offset = offset }
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} });
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return(index);
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}
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int add_munmap(unsigned long addr, unsigned long len, struct host_vm_op *ops,
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int index, int last_filled, union mm_context *mmu,
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void (*do_ops)(union mm_context *, struct host_vm_op *, int))
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{
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struct host_vm_op *last;
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if(index != -1){
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last = &ops[index];
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if((last->type == MUNMAP) &&
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(last->u.munmap.addr + last->u.mmap.len == addr)){
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last->u.munmap.len += len;
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return(index);
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}
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}
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if(index == last_filled){
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(*do_ops)(mmu, ops, last_filled);
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index = -1;
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}
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ops[++index] = ((struct host_vm_op) { .type = MUNMAP,
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.u = { .munmap = {
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.addr = addr,
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.len = len } } });
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return(index);
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}
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int add_mprotect(unsigned long addr, unsigned long len, int r, int w, int x,
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struct host_vm_op *ops, int index, int last_filled,
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union mm_context *mmu,
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void (*do_ops)(union mm_context *, struct host_vm_op *, int))
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{
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struct host_vm_op *last;
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if(index != -1){
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last = &ops[index];
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if((last->type == MPROTECT) &&
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(last->u.mprotect.addr + last->u.mprotect.len == addr) &&
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(last->u.mprotect.r == r) && (last->u.mprotect.w == w) &&
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(last->u.mprotect.x == x)){
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last->u.mprotect.len += len;
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return(index);
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}
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}
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if(index == last_filled){
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(*do_ops)(mmu, ops, last_filled);
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index = -1;
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}
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ops[++index] = ((struct host_vm_op) { .type = MPROTECT,
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.u = { .mprotect = {
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.addr = addr,
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.len = len,
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.r = r,
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.w = w,
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.x = x } } });
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return(index);
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}
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void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
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{
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address &= PAGE_MASK;
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