From 764376196a1169edd9ef5b84d970fd5e393c784f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=BE=90=E6=AD=A5=E9=AA=A5?= <xubuji20@mails.ucas.ac.cn>
Date: Tue, 1 Aug 2023 18:05:23 +0800
Subject: [PATCH] fix: do swap before memory is used out
---
kernel/include/mem.h | 3 +++
kernel/irq/irq.cpp | 9 ++++++---
kernel/mem/mem.cpp | 20 ++++++++++++++++++--
3 files changed, 27 insertions(+), 5 deletions(-)
diff --git a/kernel/include/mem.h b/kernel/include/mem.h
index 7e2cb02..312744d 100644
--- a/kernel/include/mem.h
+++ b/kernel/include/mem.h
@@ -62,6 +62,7 @@ private:
SpinLock m_lock;
size_t m_max_order;
Slice<Node *> m_lists;
+ size_t free_mem_size;
void remove_node(Node *node, size_t order);
void insert_node(Node *node, size_t order);
@@ -74,6 +75,8 @@ protected:
void __free(void *ptr, size_t len) override;
public:
+ int in_swap_process = 0;
+
BuddyAllocator() = default;
void init(Slice<byte> buffer);
diff --git a/kernel/irq/irq.cpp b/kernel/irq/irq.cpp
index ff10198..37eca1a 100644
--- a/kernel/irq/irq.cpp
+++ b/kernel/irq/irq.cpp
@@ -56,14 +56,18 @@ void handle_exc_page_fault(Context *c)
// try kill process
exit(1);
}
+ uintptr_t page_aligned_stval = c->stval & ~0xfff;
if (c->scause == EXC_INST_PAGE_FAULT) {
- // TODO: swap
- // assert(0);
+ if (is_swapped_page(hart[hartid].proc, page_aligned_stval)) {
+ do_swap_in(hart[hartid].proc, page_aligned_stval);
+ return;
+ }
fmt::warn("Inst Page Fault: kill {}({})\n", hart[hartid].proc->pid, hart[hartid].proc->name);
dump_context(c);
exit(1);
return;
}
+ ensure_user_addr((uintptr_t)c->sepc & ~0xfff, 1);
uint16_t inst_lo = *((uint16_t *)c->sepc);
uint16_t inst_hi = *((uint16_t *)c->sepc + 2);
uint32_t inst = ((uint32_t)inst_hi << 16) | inst_lo; // FIXME: compressed inst on page boundary
@@ -125,7 +129,6 @@ void handle_exc_page_fault(Context *c)
}
uint32_t opcode = inst & 0x7f;
uint32_t amo_func = (inst & 0xf8000000) >> 27;
- uintptr_t page_aligned_stval = c->stval & ~0xfff;
if (opcode == 0x3 || (opcode == 0x2f && amo_func == 0x10)) /* load */
{
if (is_swapped_page(hart[hartid].proc, page_aligned_stval)) {
diff --git a/kernel/mem/mem.cpp b/kernel/mem/mem.cpp
index c2947b3..f93c41f 100644
--- a/kernel/mem/mem.cpp
+++ b/kernel/mem/mem.cpp
@@ -60,6 +60,7 @@ Optional<void *> BuddyAllocator::__try_alloc(size_t size, size_t alignment) {
power <<= 1;
order++;
}
+ free_mem_size -= PAGE_SIZE << order;
size_t order2 = order;
size_t power2 = power;
@@ -83,11 +84,16 @@ Optional<void *> BuddyAllocator::__try_alloc(size_t size, size_t alignment) {
}
Optional<void *> BuddyAllocator::__alloc(size_t size, size_t alignment) {
+ pcb_t *proc = get_current_proc();
+ if (in_swap_process == 0 && free_mem_size <= 8 * LARGE_PAGE_SIZE) {
+ for (size_t npage = 1; npage <= 512; npage++) {
+ if (do_swap_out_proc(proc, 1) == 0) break;
+ }
+ }
auto result = __try_alloc(size, alignment);
if (result.has_value()) return result.value();
- pcb_t *proc = get_current_proc();
for (size_t npage = 1; npage <= 512; npage++) {
- do_swap_out_proc(proc, 1);
+ if (do_swap_out_proc(proc, 1) == 0) break;
result = __try_alloc(size, alignment);
if (result.has_value()) return result.value();
}
@@ -96,6 +102,7 @@ Optional<void *> BuddyAllocator::__alloc(size_t size, size_t alignment) {
void BuddyAllocator::__free(void *ptr, size_t len) {
LockGuard locked(&m_lock);
+ free_mem_size += len;
size_t order = 0;
size_t power = UNIT;
while (power < len) {
@@ -158,6 +165,7 @@ void BuddyAllocator::init(Slice<byte> buffer) {
free_mem = free_mem.slice(UNIT - align_offset, free_mem.size());
}
free_mem = free_mem.slice(0, free_mem.size() - free_mem.size() % UNIT);
+ free_mem_size = free_mem.size();
set(m_lists, static_cast<Node *>(nullptr));
size_t count = 0;
@@ -377,6 +385,8 @@ void do_swap_read(int blk_num, uintptr_t kvaddr) {
}
void do_swap_out(pcb_t *owner, uintptr_t vaddr) {
+ buddy_allocator->in_swap_process++;
+
assert(owner->user_page_list->m_value.find(vaddr) != owner->user_page_list->m_value.end());
mcb_t *mcb = owner->user_page_list->m_value[vaddr];
uintptr_t kvaddr = walk(owner->pgdir->m_value, vaddr).value();
@@ -393,9 +403,13 @@ void do_swap_out(pcb_t *owner, uintptr_t vaddr) {
remap3(holder.second->pgdir->m_value, holder.first, 0, new_flags);
}
buddy_allocator->free(Slice<byte>((byte *)kvaddr, PAGE_SIZE));
+
+ buddy_allocator->in_swap_process--;
}
void do_swap_in(pcb_t *owner, uintptr_t vaddr) {
+ buddy_allocator->in_swap_process++;
+
assert(owner->user_page_list->m_value.find(vaddr) != owner->user_page_list->m_value.end());
mcb_t *mcb = owner->user_page_list->m_value[vaddr];
assert(mcb->swapped_block > 0);
@@ -410,6 +424,8 @@ void do_swap_in(pcb_t *owner, uintptr_t vaddr) {
#endif
mcb->swapped_block = 0;
mcb->swapped_flags = 0;
+
+ buddy_allocator->in_swap_process--;
}
// mode > 0, collect $mode pages
--
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