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[Qemu-devel] [PATCH v1 6/6] mem: change tcg code to rcu style
From: |
Liu Ping Fan |
Subject: |
[Qemu-devel] [PATCH v1 6/6] mem: change tcg code to rcu style |
Date: |
Wed, 29 May 2013 10:11:09 +0800 |
From: Liu Ping Fan <address@hidden>
When adopting rcu style, for tcg code, need to fix two kind of path:
-tlb_set_page() will cache translation info.
-instruction emualation path
Signed-off-by: Liu Ping Fan <address@hidden>
----
Not sure about tcg code, so I took helper_st as the example.
---
cputlb.c | 25 +++++++++++++++++-
exec.c | 2 +-
include/exec/softmmu_template.h | 53 +++++++++++++++++++++++++++++++-------
3 files changed, 68 insertions(+), 12 deletions(-)
diff --git a/cputlb.c b/cputlb.c
index 86666c8..6b55c70 100644
--- a/cputlb.c
+++ b/cputlb.c
@@ -249,6 +249,10 @@ void tlb_set_page(CPUArchState *env, target_ulong vaddr,
uintptr_t addend;
CPUTLBEntry *te;
hwaddr iotlb, xlat, sz;
+ unsigned long start;
+ Node *map_base;
+ MemoryRegionSection *sections_base;
+ PhysPageEntry *roots_base;
assert(size >= TARGET_PAGE_SIZE);
if (size != TARGET_PAGE_SIZE) {
@@ -256,8 +260,18 @@ void tlb_set_page(CPUArchState *env, target_ulong vaddr,
}
sz = size;
+
+reload:
+ rcu_read_lock();
+ start = seqlock_read_begin(&dispatch_table_lock);
+ map_base = cur_map_nodes;
+ sections_base = cur_phys_sections;
+ roots_base = cur_roots;
section = address_space_translate(&address_space_memory, paddr, &xlat, &sz,
- false);
+ false,
+ map_base,
+ sections_base,
+ roots_base);
assert(sz >= TARGET_PAGE_SIZE);
#if defined(DEBUG_TLB)
@@ -282,6 +296,9 @@ void tlb_set_page(CPUArchState *env, target_ulong vaddr,
index = (vaddr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
env->iotlb[mmu_idx][index] = iotlb - vaddr;
+ /* Serialized with reader, so only need to worry about tlb_flush
+ * in parellel. If there is conflict, just reload tlb entry until right.
+ */
te = &env->tlb_table[mmu_idx][index];
te->addend = addend - vaddr;
if (prot & PAGE_READ) {
@@ -309,6 +326,12 @@ void tlb_set_page(CPUArchState *env, target_ulong vaddr,
} else {
te->addr_write = -1;
}
+
+ if (unlikely(seqlock_read_check(&dispatch_table_lock, start))) {
+ rcu_read_unlock();
+ goto reload;
+ }
+ rcu_read_unlock();
}
/* NOTE: this function can trigger an exception */
diff --git a/exec.c b/exec.c
index 9a5c67f..d4ca101 100644
--- a/exec.c
+++ b/exec.c
@@ -1820,7 +1820,6 @@ static void core_commit(MemoryListener *listener)
cur_phys_sections = next_phys_sections;
cur_alloc_info = next_alloc_info;
cur_roots = next_roots;
- seqlock_write_unlock(&dispatch_table_lock);
/* since each CPU stores ram addresses in its TLB cache, we must
reset the modified entries */
@@ -1828,6 +1827,7 @@ static void core_commit(MemoryListener *listener)
for (env = first_cpu; env != NULL; env = env->next_cpu) {
tlb_flush(env, 1);
}
+ seqlock_write_unlock(&dispatch_table_lock);
/* Fix me, will changed to call_rcu */
release_dispatch_map(info);
diff --git a/include/exec/softmmu_template.h b/include/exec/softmmu_template.h
index 8584902..7fa631e 100644
--- a/include/exec/softmmu_template.h
+++ b/include/exec/softmmu_template.h
@@ -196,13 +196,16 @@ static void glue(glue(slow_st, SUFFIX),
MMUSUFFIX)(CPUArchState *env,
int mmu_idx,
uintptr_t retaddr);
+/* Caller hold rcu read lock, this func will release lock */
static inline void glue(io_write, SUFFIX)(CPUArchState *env,
hwaddr physaddr,
DATA_TYPE val,
target_ulong addr,
- uintptr_t retaddr)
+ uintptr_t retaddr,
+ MemoryRegionSection *mrs_base)
{
- MemoryRegion *mr = iotlb_to_region(physaddr);
+ subpage_t *subpg;
+ MemoryRegion *mr = mrs_base[[physaddr & ~TARGET_PAGE_MASK].mr;
physaddr = (physaddr & TARGET_PAGE_MASK) + addr;
if (mr != &io_mem_rom && mr != &io_mem_notdirty && !can_do_io(env)) {
@@ -211,6 +214,13 @@ static inline void glue(io_write, SUFFIX)(CPUArchState
*env,
env->mem_io_vaddr = addr;
env->mem_io_pc = retaddr;
+ if (!mr->terminates) {
+ subpg = container_of(mr, subpage_t, mmio);
+ idx = SUBPAGE_IDX(addr);
+ mr = mrs_base[subpg->sections[idx]].mr;
+ }
+ memory_region_ref(mr);
+ rcu_read_unlock();
io_mem_write(mr, physaddr, val, 1 << SHIFT);
}
@@ -222,17 +232,28 @@ void glue(glue(helper_st, SUFFIX),
MMUSUFFIX)(CPUArchState *env,
target_ulong tlb_addr;
uintptr_t retaddr;
int index;
+ unsigned int start;
+ MemoryRegionSection *mrs_base;
+ uintptr_t addend;
index = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
redo:
- tlb_addr = env->tlb_table[mmu_idx][index].addr_write;
+ rcu_read_lock();
+ do {
+ start = seqlock_read_begin(&dispatch_table_lock);
+ tlb_addr = env->tlb_table[mmu_idx][index].addr_write;
+ ioaddr = env->iotlb[mmu_idx][index];
+ addend = env->tlb_table[mmu_idx][index].addend;
+ mrs_base = cur_phys_sections;
+ } while (seqlock_read_check(&dispatch_table_lock, start));
+
if ((addr & TARGET_PAGE_MASK) == (tlb_addr & (TARGET_PAGE_MASK |
TLB_INVALID_MASK))) {
if (tlb_addr & ~TARGET_PAGE_MASK) {
/* IO access */
if ((addr & (DATA_SIZE - 1)) != 0)
goto do_unaligned_access;
retaddr = GETPC_EXT();
- ioaddr = env->iotlb[mmu_idx][index];
+ /* will rcu_read_unlock() inside */
glue(io_write, SUFFIX)(env, ioaddr, val, addr, retaddr);
} else if (((addr & ~TARGET_PAGE_MASK) + DATA_SIZE - 1) >=
TARGET_PAGE_SIZE) {
do_unaligned_access:
@@ -240,22 +261,23 @@ void glue(glue(helper_st, SUFFIX),
MMUSUFFIX)(CPUArchState *env,
#ifdef ALIGNED_ONLY
do_unaligned_access(env, addr, 1, mmu_idx, retaddr);
#endif
+ rcu_read_unlock();
glue(glue(slow_st, SUFFIX), MMUSUFFIX)(env, addr, val,
mmu_idx, retaddr);
} else {
/* aligned/unaligned access in the same page */
- uintptr_t addend;
#ifdef ALIGNED_ONLY
if ((addr & (DATA_SIZE - 1)) != 0) {
retaddr = GETPC_EXT();
do_unaligned_access(env, addr, 1, mmu_idx, retaddr);
}
#endif
- addend = env->tlb_table[mmu_idx][index].addend;
glue(glue(st, SUFFIX), _raw)((uint8_t *)(intptr_t)
(addr + addend), val);
+ rcu_read_unlock();
}
} else {
+ rcu_read_unlock();
/* the page is not in the TLB : fill it */
retaddr = GETPC_EXT();
#ifdef ALIGNED_ONLY
@@ -277,17 +299,25 @@ static void glue(glue(slow_st, SUFFIX),
MMUSUFFIX)(CPUArchState *env,
hwaddr ioaddr;
target_ulong tlb_addr;
int index, i;
+ uintptr_t addend;
index = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
redo:
- tlb_addr = env->tlb_table[mmu_idx][index].addr_write;
+ rcu_read_lock();
+ do {
+ start = seqlock_read_begin(&dispatch_table_lock);
+ tlb_addr = env->tlb_table[mmu_idx][index].addr_write;
+ ioaddr = env->iotlb[mmu_idx][index];
+ addend = env->tlb_table[mmu_idx][index].addend;
+ mrs_base = cur_phys_sections;
+ } while (seqlock_read_check(&dispatch_table_lock, start));
+
if ((addr & TARGET_PAGE_MASK) == (tlb_addr & (TARGET_PAGE_MASK |
TLB_INVALID_MASK))) {
if (tlb_addr & ~TARGET_PAGE_MASK) {
/* IO access */
if ((addr & (DATA_SIZE - 1)) != 0)
goto do_unaligned_access;
- ioaddr = env->iotlb[mmu_idx][index];
- glue(io_write, SUFFIX)(env, ioaddr, val, addr, retaddr);
+ glue(io_write, SUFFIX)(env, ioaddr, val, addr, retaddr, mrs_base);
} else if (((addr & ~TARGET_PAGE_MASK) + DATA_SIZE - 1) >=
TARGET_PAGE_SIZE) {
do_unaligned_access:
/* XXX: not efficient, but simple */
@@ -295,10 +325,12 @@ static void glue(glue(slow_st, SUFFIX),
MMUSUFFIX)(CPUArchState *env,
* previous page from the TLB cache. */
for(i = DATA_SIZE - 1; i >= 0; i--) {
#ifdef TARGET_WORDS_BIGENDIAN
+ rcu_read_unlock();
glue(slow_stb, MMUSUFFIX)(env, addr + i,
val >> (((DATA_SIZE - 1) * 8) - (i *
8)),
mmu_idx, retaddr);
#else
+ rcu_read_unlock();
glue(slow_stb, MMUSUFFIX)(env, addr + i,
val >> (i * 8),
mmu_idx, retaddr);
@@ -306,11 +338,12 @@ static void glue(glue(slow_st, SUFFIX),
MMUSUFFIX)(CPUArchState *env,
}
} else {
/* aligned/unaligned access in the same page */
- uintptr_t addend = env->tlb_table[mmu_idx][index].addend;
glue(glue(st, SUFFIX), _raw)((uint8_t *)(intptr_t)
(addr + addend), val);
+ rcu_read_unlock();
}
} else {
+ rcu_read_unlock();
/* the page is not in the TLB : fill it */
tlb_fill(env, addr, 1, mmu_idx, retaddr);
goto redo;
--
1.7.4.4