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[kernel] Remove obsolete 'mappings' list from VMAs

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The vm_area_shared type of VMA used to track mappings in a separate
array, which doubled information and wasted space. This was no longer
used, and is now removed.
This commit is contained in:
Justin C. Miller
2020-09-27 21:47:35 -07:00
parent 87b0a93d32
commit da38006f44
2 changed files with 0 additions and 159 deletions
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139
src/kernel/objects/vm_area.cpp
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@@ -52,145 +52,6 @@ vm_area_shared::~vm_area_shared()
{
}
size_t
vm_area_shared::overlaps(uintptr_t offset, size_t pages, size_t *count)
{
size_t first = 0;
size_t n = 0;
uintptr_t end = offset + pages * frame_size;
for (size_t i = 0; i < m_mappings.count(); ++i) {
mapping &m = m_mappings[i];
uintptr_t map_end = m.offset + m.count * frame_size;
if (offset < map_end && end > m.offset) {
if (!first) first = i;
++n;
} else if (n) {
break;
}
}
if (count) *count = n;
return first;
}
void
vm_area_shared::commit(uintptr_t phys, uintptr_t offset, size_t count)
{
size_t n = 0;
size_t o = overlaps(offset, count, &n);
// Mapping overlaps not allowed
if (n) return;
m_mapper.map(offset, count, phys);
o = m_mappings.sorted_insert({
.offset = offset,
.count = count,
.phys = phys});
n = 1;
// Try to expand to abutting similar areas
if (o > 0 &&
m_mappings[o-1].end() == offset &&
m_mappings[o-1].phys_end() == phys) {
--o;
++n;
}
uintptr_t end = offset + count * frame_size;
uintptr_t pend = phys + count * frame_size;
if (o + n < m_mappings.count() &&
end == m_mappings[o+n].offset &&
m_mappings[o-1].phys == pend) {
++n;
}
// Use the first overlap block as our new block
mapping &first = m_mappings[o];
mapping &last = m_mappings[o + n -1];
if (offset < first.offset)
first.offset = offset;
size_t diff =
(end > last.end() ? end : last.end()) -
first.offset;
first.count = memory::page_count(diff);
if (n > 1)
m_mappings.remove_at(o+1, n-1);
return;
}
void
vm_area_shared::uncommit(uintptr_t offset, size_t count)
{
size_t n = 0;
size_t o = overlaps(offset, count, &n);
if (!n) return;
m_mapper.unmap(offset, count);
mapping *first = &m_mappings[o];
mapping *last = &m_mappings[o+n-1];
uintptr_t end = offset + count * frame_size;
size_t leading = offset - first->offset;
size_t trailing = last->end() - end;
// if were entirely contained in one, we need to split it
if (leading && trailing && n == 1) {
size_t i = m_mappings.sorted_insert({
.offset = end,
.count = trailing / frame_size,
});
last = &m_mappings[i];
trailing = 0;
first->count -= last->count;
last->phys = first->phys + first->count * frame_size;
}
if (leading) {
size_t remove_pages = first->count;
first->count = leading / frame_size;
remove_pages -= first->count;
m_mapper.unmap(first->end(), remove_pages);
}
if (trailing) {
uintptr_t remove_off = last->offset;
size_t remove_pages = last->count;
last->offset = end;
last->count = trailing / frame_size;
remove_pages -= last->count;
m_mapper.unmap(remove_off, remove_pages);
last->phys += remove_pages * frame_size;
}
size_t delete_start = 0;
size_t delete_count = 0;
for (size_t i = o; i < o+n; ++i) {
mapping &m = m_mappings[i];
if (offset <= m.offset && end >= m.end()) {
if (!delete_count) delete_start = i;
++delete_count;
m_mapper.unmap(m.offset, m.count);
}
}
if (delete_count)
m_mappings.remove_at(delete_start, delete_count);
return;
}
vm_area_open::vm_area_open(size_t size, vm_space &space, vm_flags flags) :
m_mapper(*this, space),