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Try to avoid OOM killer on low-memory systems without swap.

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Benchmark for memory-hard KDF is tricky, seems that relying
on maximum half of physical memory is not enough.

Let's allow only free physical available space if there is no swap.
This should not cause changes on normal systems, at least.
This commit is contained in:
Milan Broz
2023-02-20 16:45:36 +01:00
parent 62aa392205
commit 899bad8c06
4 changed files with 67 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
lib/internal.h
View File

@@ -168,6 +168,8 @@ int crypt_uuid_cmp(const char *dm_uuid, const char *hdr_uuid);
size_t crypt_getpagesize(void);
unsigned crypt_cpusonline(void);
uint64_t crypt_getphysmemory_kb(void);
uint64_t crypt_getphysmemoryfree_kb(void);
bool crypt_swapavailable(void);
int init_crypto(struct crypt_device *ctx);

47
lib/utils.c
View File

@@ -59,6 +59,53 @@ uint64_t crypt_getphysmemory_kb(void)
return phys_memory_kb;
}
uint64_t crypt_getphysmemoryfree_kb(void)
{
long pagesize, phys_pages;
uint64_t phys_memoryfree_kb;
pagesize = sysconf(_SC_PAGESIZE);
phys_pages = sysconf(_SC_AVPHYS_PAGES);
if (pagesize < 0 || phys_pages < 0)
return 0;
phys_memoryfree_kb = pagesize / 1024;
phys_memoryfree_kb *= phys_pages;
return phys_memoryfree_kb;
}
bool crypt_swapavailable(void)
{
int fd;
ssize_t size;
char buf[4096], *p;
uint64_t total;
if ((fd = open("/proc/meminfo", O_RDONLY)) < 0)
return true;
size = read(fd, buf, sizeof(buf));
close(fd);
if (size < 1)
return true;
if (size < (ssize_t)sizeof(buf))
buf[size] = 0;
else
buf[sizeof(buf) - 1] = 0;
p = strstr(buf, "SwapTotal:");
if (!p)
return true;
if (sscanf(p, "SwapTotal: %" PRIu64 " kB", &total) != 1)
return true;
return total > 0;
}
void crypt_process_priority(struct crypt_device *cd, int *priority, bool raise)
{
int _priority, new_priority;

11
lib/utils_pbkdf.c
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@@ -63,7 +63,7 @@ const struct crypt_pbkdf_type *crypt_get_pbkdf_type_params(const char *pbkdf_typ
static uint32_t adjusted_phys_memory(void)
{
uint64_t memory_kb = crypt_getphysmemory_kb();
uint64_t free_kb, memory_kb = crypt_getphysmemory_kb();
/* Ignore bogus value */
if (memory_kb < (128 * 1024) || memory_kb > UINT32_MAX)
@@ -75,6 +75,15 @@ static uint32_t adjusted_phys_memory(void)
*/
memory_kb /= 2;
/*
* Never use more that available free space on system without swap.
*/
if (!crypt_swapavailable()) {
free_kb = crypt_getphysmemoryfree_kb();
if (free_kb > (64 * 1024) && free_kb < memory_kb)
return free_kb;
}
return memory_kb;
}

12
tests/api-test-2.c
View File

@@ -2802,7 +2802,8 @@ static void Pbkdf(void)
OK_(strcmp(pbkdf->type, default_luks2_pbkdf));
OK_(strcmp(pbkdf->hash, default_luks1_hash));
EQ_(pbkdf->time_ms, default_luks2_iter_time);
EQ_(pbkdf->max_memory_kb, adjusted_pbkdf_memory());
GE_(pbkdf->max_memory_kb, 64 * 1024);
GE_(adjusted_pbkdf_memory(), pbkdf->max_memory_kb);
EQ_(pbkdf->parallel_threads, _min(cpus_online(), default_luks2_parallel_threads));
// set and verify argon2 type
OK_(crypt_set_pbkdf_type(cd, &argon2));
@@ -2827,7 +2828,8 @@ static void Pbkdf(void)
OK_(strcmp(pbkdf->type, default_luks2_pbkdf));
OK_(strcmp(pbkdf->hash, default_luks1_hash));
EQ_(pbkdf->time_ms, default_luks2_iter_time);
EQ_(pbkdf->max_memory_kb, adjusted_pbkdf_memory());
GE_(pbkdf->max_memory_kb, 64 * 1024);
GE_(adjusted_pbkdf_memory(), pbkdf->max_memory_kb);
EQ_(pbkdf->parallel_threads, _min(cpus_online(), default_luks2_parallel_threads));
// try to pass illegal values
argon2.parallel_threads = 0;
@@ -2858,14 +2860,16 @@ static void Pbkdf(void)
OK_(strcmp(pbkdf->type, default_luks2_pbkdf));
OK_(strcmp(pbkdf->hash, default_luks1_hash));
EQ_(pbkdf->time_ms, default_luks2_iter_time);
EQ_(pbkdf->max_memory_kb, adjusted_pbkdf_memory());
GE_(pbkdf->max_memory_kb, 64 * 1024);
GE_(adjusted_pbkdf_memory(), pbkdf->max_memory_kb);
EQ_(pbkdf->parallel_threads, _min(cpus_online(), default_luks2_parallel_threads));
crypt_set_iteration_time(cd, 1);
OK_(crypt_load(cd, CRYPT_LUKS, NULL));
OK_(strcmp(pbkdf->type, default_luks2_pbkdf));
OK_(strcmp(pbkdf->hash, default_luks1_hash));
EQ_(pbkdf->time_ms, 1);
EQ_(pbkdf->max_memory_kb, adjusted_pbkdf_memory());
GE_(pbkdf->max_memory_kb, 64 * 1024);
GE_(adjusted_pbkdf_memory(), pbkdf->max_memory_kb);
EQ_(pbkdf->parallel_threads, _min(cpus_online(), default_luks2_parallel_threads));
CRYPT_FREE(cd);