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namecache: prefer to evict child entries over parents

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renamed name_cache_entry_refresh() to name_cache_entry_updated().  this function resets the entry's expiration timer.  new function name_cache_entry_accessed() deals with moving the entry to the end of exp_entries to prevent eviction

name_cache_entry_accessed() now does the same for its parents as well.  cache consistency of the parents is maintained because their expiration timers are unchanged.  by 'refreshing' the parents of each name cache entry inserted, the eviction policy will always prefer child nodes (which are far less costly to evict)

Signed-off-by: Casey Bodley <cbodley@citi.umich.edu>
This commit is contained in:
Casey Bodley 2011-08-25 10:52:19 -04:00 • committed by unknown
parent 0d86c68138
commit 6c555e028b
1 changed files with 23 additions and 9 deletions
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32
daemon/name_cache.c
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@ -455,17 +455,31 @@ static int name_cache_entry_create(
return status; return status;
} }
static void name_cache_entry_refresh( static void name_cache_entry_accessed(
IN struct nfs41_name_cache *cache,
IN struct name_cache_entry *entry)
{
/* move the entry to the front of cache->exp_entries, then do
* the same for its parents, which are more costly to evict */
while (entry) {
/* if entry is delegated, it won't be in the list */
if (!list_empty(&entry->exp_entry)) {
list_remove(&entry->exp_entry);
list_add_head(&cache->exp_entries, &entry->exp_entry);
}
if (entry == entry->parent)
break;
entry = entry->parent;
}
}
static void name_cache_entry_updated(
IN struct nfs41_name_cache *cache, IN struct nfs41_name_cache *cache,
IN struct name_cache_entry *entry) IN struct name_cache_entry *entry)
{ {
/* update the expiration timer */ /* update the expiration timer */
entry->expiration = time(NULL) + cache->expiration; entry->expiration = time(NULL) + cache->expiration;
/* move the entry to the front of cache->exp_entries */ name_cache_entry_accessed(cache, entry);
if (!list_empty(&entry->exp_entry)) {
list_remove(&entry->exp_entry);
list_add_head(&cache->exp_entries, &entry->exp_entry);
}
} }
static int name_cache_entry_update( static int name_cache_entry_update(
@ -506,7 +520,7 @@ static int name_cache_entry_update(
attr_cache_entry_deref(&cache->attributes, entry->attributes); attr_cache_entry_deref(&cache->attributes, entry->attributes);
entry->attributes = NULL; entry->attributes = NULL;
} }
name_cache_entry_refresh(cache, entry); name_cache_entry_updated(cache, entry);
return status; return status;
} }
@ -521,7 +535,7 @@ static int name_cache_entry_changed(
if (cinfo->after == entry->attributes->change || if (cinfo->after == entry->attributes->change ||
(cinfo->atomic && cinfo->before == entry->attributes->change)) { (cinfo->atomic && cinfo->before == entry->attributes->change)) {
entry->attributes->change = cinfo->after; entry->attributes->change = cinfo->after;
name_cache_entry_refresh(cache, entry); name_cache_entry_updated(cache, entry);
dprintf(NCLVL1, "name_cache_entry_changed('%s') has not changed. " dprintf(NCLVL1, "name_cache_entry_changed('%s') has not changed. "
"updated change=%llu\n", entry->component, "updated change=%llu\n", entry->component,
entry->attributes->change); entry->attributes->change);
@ -978,7 +992,7 @@ int nfs41_name_cache_delegreturn(
if (status == NO_ERROR) { if (status == NO_ERROR) {
/* put the name cache entry back on the exp_entries list */ /* put the name cache entry back on the exp_entries list */
list_add_head(&cache->exp_entries, &target->exp_entry); list_add_head(&cache->exp_entries, &target->exp_entry);
name_cache_entry_refresh(cache, target); name_cache_entry_updated(cache, target);
attributes = target->attributes; attributes = target->attributes;
} else { } else {