Hello Dave,
These two patches are used to improve the performance of "kmem -s
[address]".
Current code need to search all kmem_caches twice. It is a waste of
time. With my patch, the address is sent to "dump_kmem_cache" function
to make the second search be restricted to the kmem_cache found in the
first search. It means the second search is neglected.
I have implemented the improvement for three types of kmem_cache. The
search for "slub" does not waste that much time as its peers, so I did
not modify the code related to "slub". Additionally, I only get the
environment to test my first patch, so the second patch has not been tested.
Here is the statistic of my test on RHEL6.2 x86_64, the vmcore used for
testing has about 150000 kmem_caches
commands in file:
1. only 'quit'
origin code : about 36s
with patch : about 36s
2. 1 time of searching the 100000th kmem_cache
origin code : about 59s
with patch : about 39s
3. 100 times of searching the 100000th kmem_cache
origin code : about 38min30s
with patch : about 5min
p.s.
If I create a kmem_cache called "list", a little confusion may happen
when using "kmem -s list". I am wondering is it necessary to introduce
an another option replacing list to avoid such collision.
--
--
Regards
Qiao Nuohan
diff --git a/memory.c b/memory.c
index 95eefc9..2ec44ab 100755
--- a/memory.c
+++ b/memory.c
@@ -4091,6 +4091,7 @@ cmd_kmem(void)
error(FATAL,
"only one kmem_cache reference is allowed\n");
meminfo.reqname = p1;
+ meminfo.cache = value[i];
if ((i+1) == spec_addr) { /* done? */
if (meminfo.calls++)
fprintf(fp, "\n");
@@ -7589,15 +7590,12 @@ is_kmem_cache_addr(ulong vaddr, char *kbuf)
cache_buf = GETBUF(SIZE(kmem_cache_s));
do {
- readmem(cache, KVADDR, cache_buf, SIZE(kmem_cache_s),
- "kmem_cache buffer", FAULT_ON_ERROR);
if (cache == vaddr) {
if (vt->kmem_cache_namelen) {
- BCOPY(cache_buf+name_offset, kbuf,
- vt->kmem_cache_namelen);
+ readmem(cache+name_offset, KVADDR, kbuf, vt->kmem_cache_namelen, "name array", FAULT_ON_ERROR);
} else {
- name = ULONG(cache_buf + name_offset);
+ readmem(cache+name_offset, KVADDR, &name, sizeof(name), "name", FAULT_ON_ERROR);
if (!read_string(name, kbuf, BUFSIZE-1)) {
if (vt->flags &
(PERCPU_KMALLOC_V1|PERCPU_KMALLOC_V2))
@@ -7615,7 +7613,8 @@ is_kmem_cache_addr(ulong vaddr, char *kbuf)
return kbuf;
}
- cache = ULONG(cache_buf + next_offset);
+ readmem(cache+next_offset, KVADDR, &cache, sizeof(long),
+ "kmem_cache_s next", FAULT_ON_ERROR);
if (vt->flags & (PERCPU_KMALLOC_V1|PERCPU_KMALLOC_V2))
cache -= next_offset;
@@ -8733,9 +8732,15 @@ dump_kmem_cache_percpu_v2(struct meminfo *si)
cnt = 0;
- get_symbol_data("cache_chain", sizeof(ulong), &si->cache);
- si->cache -= OFFSET(kmem_cache_s_next);
- cache_end = symbol_value("cache_chain");
+ if (si->cache) {
+ readmem(si->cache+OFFSET(kmem_cache_s_next),
+ KVADDR, &cache_end, sizeof(ulong),
+ "kmem_cache_s next", FAULT_ON_ERROR);
+ } else {
+ get_symbol_data("cache_chain", sizeof(ulong), &si->cache);
+ si->cache -= OFFSET(kmem_cache_s_next);
+ cache_end = symbol_value("cache_chain");
+ }
if (si->flags & ADDRESS_SPECIFIED) {
if (!(p1 = vaddr_to_kmem_cache(si->spec_addr, kbuf, VERBOSE))) {
diff --git a/memory.c b/memory.c
index 2ec44ab..27a5346 100755
--- a/memory.c
+++ b/memory.c
@@ -8303,7 +8303,13 @@ dump_kmem_cache(struct meminfo *si)
si->addrlist = (ulong *)GETBUF((vt->kmem_max_c_num+1) * sizeof(ulong));
cnt = 0;
- si->cache = cache_cache = symbol_value("cache_cache");
+ if (si->cache) {
+ readmem(si->cache+OFFSET(kmem_cache_s_c_nextp),
+ KVADDR, &cache_cache, sizeof(ulong),
+ "kmem_cache next", FAULT_ON_ERROR);
+ } else {
+ si->cache = cache_cache = symbol_value("cache_cache");
+ }
if (si->flags & ADDRESS_SPECIFIED) {
if (!(p1 = vaddr_to_kmem_cache(si->spec_addr, kbuf, VERBOSE))) {
@@ -8509,7 +8515,13 @@ dump_kmem_cache_percpu_v1(struct meminfo *si)
GETBUF(vt->kmem_max_limit * sizeof(ulong));
cnt = 0;
- si->cache = cache_cache = symbol_value("cache_cache");
+ if (si->cache) {
+ readmem(si->cache+OFFSET(kmem_cache_s_next),
+ KVADDR, &cache_cache, sizeof(ulong),
+ "kmem_cache_s next", FAULT_ON_ERROR);
+ } else {
+ si->cache = cache_cache = symbol_value("cache_cache");
+ }
if (si->flags & ADDRESS_SPECIFIED) {
if (!(p1 = vaddr_to_kmem_cache(si->spec_addr, kbuf, VERBOSE))) {
--
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