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team: randomize position of team user data

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When forking a process team user data area is not cloned but a new one is
created instead. However, the new one has to be at exactly the same address
parent's team user data area is. When process is exec then team user data
area may be recreated at random position.

This patch also make sure that instances of struct user_thread in team user
data are each in separate cache line in order to prevent false sharing since
these data are very likely to be accessed simultaneously from threads executing
on different CPUs. This change however reduces the number of threads process
can create. It is fixed by reserving 512kB of address space in case team user
data area needs to grow.
This commit is contained in:
Pawel Dziepak
2013-04-04 15:16:25 +02:00
parent 0cf91fc14f
commit 02cceebe40
1 changed files with 33 additions and 10 deletions
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src/system/kernel/team.cpp
+33 -10
View File
@@ -158,6 +158,9 @@ static int32 sUsedTeams = 1;
static TeamNotificationService sNotificationService;
static const size_t kTeamUserDataReservedSize = 128 * B_PAGE_SIZE;
static const size_t kTeamUserDataInitialSize = 4 * B_PAGE_SIZE;
// #pragma mark - TeamListIterator
@@ -1324,23 +1327,40 @@ remove_team_from_group(Team* team)
static status_t
create_team_user_data(Team* team)
create_team_user_data(Team* team, void* exactAddress = NULL)
{
void* address;
size_t size = 4 * B_PAGE_SIZE;
uint32 addressSpec;
if (exactAddress != NULL) {
address = exactAddress;
addressSpec = B_EXACT_ADDRESS;
} else
addressSpec = B_RANDOMIZED_BASE_ADDRESS;
status_t result = vm_reserve_address_range(team->id, &address, addressSpec,
kTeamUserDataReservedSize, RESERVED_AVOID_BASE);
virtual_address_restrictions virtualRestrictions = {};
virtualRestrictions.address = (void*)KERNEL_USER_DATA_BASE;
virtualRestrictions.address_specification = B_BASE_ADDRESS;
if (result == B_OK || exactAddress != NULL) {
if (exactAddress != NULL)
virtualRestrictions.address = exactAddress;
else
virtualRestrictions.address = address;
virtualRestrictions.address_specification = B_EXACT_ADDRESS;
} else
virtualRestrictions.address_specification = B_RANDOMIZED_ANY_ADDRESS;
physical_address_restrictions physicalRestrictions = {};
team->user_data_area = create_area_etc(team->id, "user area", size,
B_FULL_LOCK, B_READ_AREA | B_WRITE_AREA, 0, 0, &virtualRestrictions,
&physicalRestrictions, &address);
team->user_data_area = create_area_etc(team->id, "user area",
kTeamUserDataInitialSize, B_FULL_LOCK, B_READ_AREA | B_WRITE_AREA, 0, 0,
&virtualRestrictions, &physicalRestrictions, &address);
if (team->user_data_area < 0)
return team->user_data_area;
team->user_data = (addr_t)address;
team->used_user_data = 0;
team->user_data_size = size;
team->user_data_size = kTeamUserDataInitialSize;
team->free_user_threads = NULL;
return B_OK;
@@ -1352,6 +1372,9 @@ delete_team_user_data(Team* team)
{
if (team->user_data_area >= 0) {
vm_delete_area(team->id, team->user_data_area, true);
vm_unreserve_address_range(team->id, (void*)team->user_data,
kTeamUserDataReservedSize);
team->user_data = 0;
team->used_user_data = 0;
team->user_data_size = 0;
@@ -2035,7 +2058,7 @@ fork_team(void)
while (get_next_area_info(B_CURRENT_TEAM, &areaCookie, &info) == B_OK) {
if (info.area == parentTeam->user_data_area) {
// don't clone the user area; just create a new one
status = create_team_user_data(team);
status = create_team_user_data(team, info.address);
if (status != B_OK)
break;
@@ -3360,7 +3383,7 @@ team_allocate_user_thread(Team* team)
while (true) {
// enough space left?
size_t needed = ROUNDUP(sizeof(user_thread), 8);
size_t needed = ROUNDUP(sizeof(user_thread), 128);
if (team->user_data_size - team->used_user_data < needed) {
// try to resize the area
if (resize_area(team->user_data_area,