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fixup! [LibOS] shim_vma: optimize __get_new_vma() and __drop_vma()

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This commit is contained in:
Isaku Yamahata
2020-02-24 15:05:07 -08:00
parent 3232c7533a
commit ea46d1f9dd
1 changed files with 48 additions and 59 deletions
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LibOS/shim/src/bookkeep/shim_vma.c
+48 -59
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@@ -90,8 +90,18 @@ static inline void * __malloc (size_t size)
PAL_PROT_WRITE|PAL_PROT_READ);
}
void __free(void* addr, size_t size) {
__UNUSED(addr);
__UNUSED(size);
/* g_vma_mgr is never destroyed. */
__abort();
}
#undef system_malloc
#define system_malloc __malloc
#undef system_free
#define system_free __free
#define OBJ_TYPE struct shim_vma
#include <memmgr.h>
@@ -101,6 +111,11 @@ static inline void * __malloc (size_t size)
* allocating or freeing any VMAs.
*/
static MEM_MGR g_vma_mgr = NULL;
/*
* If assert(!__mem_mgr_enlarged(vma_mgr)) fails, increase the size of g_vma_mgr_area for the
* needed vmas for initialization.
*/
static uint8_t g_vma_mgr_area[__MAX_MEM_SIZE(VMA_MGR_ALLOC)];
/*
* "g_vma_list" contains a sorted list of non-overlapping VMAs.
@@ -187,17 +202,6 @@ static inline void assert_vma_list (void)
#endif
}
/*
* This speeds only the case when continuously increasing addresses are looked up.
* This is easy optimization with the hope that it won't harm in cache miss case.
*
* TODO: observe memory allocation behavior and optimize for it; in particular, look at:
* - bkeep_unmapped_heap()
* - bkeep_unmapped_any() = bkeep_unmapped() used by shim_malloc.c
* - user app malloc (e.g. malloc() in glibc)
*
* Another options is to introduce rb-tree. (or other tree, e.g. splay tree)
*/
static struct shim_vma* g_lookup_cache = NULL;
static bool check_addr_vma(void* addr, struct shim_vma* vma,
@@ -217,11 +221,9 @@ static bool check_addr_vma(void* addr, struct shim_vma* vma,
/*
* __lookup_vma() returns the VMA that contains the address; otherwise,
* This speeds only the case when continuously increasing addresses are looked up.
* returns NULL. "pprev" returns the highest VMA below the address.
* __lookup_vma() fills "pprev" even when the function cannot find a
* matching vma for "addr".
* This is easy optimization with the hope that it won't harm in cache miss case.
*/
static inline struct shim_vma* __lookup_vma(void* addr, struct shim_vma** pprev) {
assert(locked(&g_vma_list_lock));
@@ -230,6 +232,17 @@ static inline struct shim_vma* __lookup_vma(void* addr, struct shim_vma** pprev)
struct shim_vma* prev = NULL;
struct shim_vma* found = NULL;
/*
* This speeds only the case when continuously increasing addresses are looked up.
* This is easy optimization with the hope that it won't harm in cache miss case.
*
* TODO: observe memory allocation behavior and optimize for it; in particular, look at:
* - bkeep_unmapped_heap()
* - bkeep_unmapped_any() = bkeep_unmapped() used by shim_malloc.c
* - user app malloc (e.g. malloc() in glibc)
*
* Another options is to introduce rb-tree. (or other tree, e.g. splay tree)
*/
if (g_lookup_cache && g_lookup_cache->end < addr) {
/* addr is after the cached address, skip to cached VMA. */
struct shim_vma* tmp;
@@ -250,6 +263,9 @@ static inline struct shim_vma* __lookup_vma(void* addr, struct shim_vma** pprev)
if (pprev) {
*pprev = prev;
if (prev) {
/* The callers with pprev = NULL are lookup_vma() and lookup_overlap_vma()
* which seems useless to update g_lookup_cache.
*/
g_lookup_cache = prev;
}
}
@@ -315,6 +331,8 @@ static int __bkeep_munmap (struct shim_vma ** prev,
static int __bkeep_mprotect (struct shim_vma * prev,
void * start, void * end, int prot, int flags);
static inline void __restore_reserved_vmas(void);
static int
__bkeep_preloaded (void * start, void * end, int prot, int flags,
const char * comment)
@@ -326,7 +344,11 @@ __bkeep_preloaded (void * start, void * end, int prot, int flags,
struct shim_vma * prev = NULL;
__lookup_vma(start, &prev);
return __bkeep_mmap(prev, start, end, prot, flags, NULL, 0, comment);
int ret = __bkeep_mmap(prev, start, end, prot, flags, NULL, 0, comment);
assert(!mem_mgr_enlarged(g_vma_mgr));
__restore_reserved_vmas();
assert(!mem_mgr_enlarged(g_vma_mgr));
return ret;
}
int init_vma(void) {
@@ -338,9 +360,14 @@ int init_vma(void) {
lock(&g_vma_list_lock);
struct shim_vma early_vmas[RESERVED_VMAS];
for (int i = 0 ; i < RESERVED_VMAS ; i++)
g_reserved_vmas[i] = &early_vmas[i];
/* Initialize the allocator */
g_vma_mgr = create_mem_mgr_in_place(g_vma_mgr_area, sizeof(g_vma_mgr_area));
assert(g_vma_mgr);
for (int i = 0; i < RESERVED_VMAS; i++) {
g_reserved_vmas[i] = get_mem_obj_from_mgr(g_vma_mgr);
assert(g_reserved_vmas[i]);
assert(!mem_mgr_enlarged(g_vma_mgr));
}
g_num_reserved_vmas = RESERVED_VMAS;
/* Bookkeeping for preloaded areas */
@@ -376,33 +403,6 @@ int init_vma(void) {
if (ret < 0)
goto out;
/* Initialize the allocator */
if (!(g_vma_mgr = create_mem_mgr(init_align_up(VMA_MGR_ALLOC)))) {
debug("failed creating the VMA allocator\n");
ret = -ENOMEM;
goto out;
}
for (int i = 0 ; i < RESERVED_VMAS ; i++) {
if (i >= g_num_reserved_vmas) {
struct shim_vma * new = get_mem_obj_from_mgr(g_vma_mgr);
assert(new);
struct shim_vma * e = &early_vmas[i];
struct shim_vma * prev = LISTP_PREV_ENTRY(e, &g_vma_list, list);
debug("Converting early VMA [%p] %p-%p\n", e, e->start, e->end);
memcpy(new, e, sizeof(*e));
INIT_LIST_HEAD(new, list);
__remove_vma(e, prev);
__insert_vma(new, prev);
}
/* replace all reserved VMAs */
g_reserved_vmas[i] = get_mem_obj_from_mgr(g_vma_mgr);
assert(g_reserved_vmas[i]);
}
g_num_reserved_vmas = RESERVED_VMAS;
current_heap_top = PAL_CB(user_address.end);
#if ENABLE_ASLR == 1
@@ -433,10 +433,7 @@ static inline struct shim_vma * __get_new_vma (void)
{
assert(locked(&g_vma_list_lock));
struct shim_vma * tmp = NULL;
if (g_vma_mgr)
tmp = get_mem_obj_from_mgr(g_vma_mgr);
struct shim_vma* tmp = get_mem_obj_from_mgr(g_vma_mgr);
if (tmp == NULL) {
if (g_num_reserved_vmas) {
tmp = g_reserved_vmas[--g_num_reserved_vmas];
@@ -457,23 +454,15 @@ static inline struct shim_vma * __get_new_vma (void)
static inline void __restore_reserved_vmas(void) {
assert(locked(&g_vma_list_lock));
/*
* On entry bkeep_mmap(), it needs to ensure that at least three reserved_vmas are available.
* After that, g_reserved_vmas needs to be re-populated.
* - one for __bkeep_munmap() => __shrink_vma()
* - one for new vma for new region
* - one for re-populating reserved_vma.
*/
if (g_num_reserved_vmas >= 3)
return;
while (g_num_reserved_vmas < RESERVED_VMAS) {
/* get_mem_obj_from_mgr_enlarge() may allocate vma for memory allocation. */
assert(g_num_reserved_vmas >= 1);
struct shim_vma * new = get_mem_obj_from_mgr_enlarge(g_vma_mgr,
size_align_up(VMA_MGR_ALLOC));
/* this allocation must succeed */
assert(new);
if (!new)
__abort();
g_reserved_vmas[g_num_reserved_vmas++] = new;
}
}