@@ -753,32 +753,19 @@ static enum fullness_group get_fullness_group(struct size_class *class,
}
/*
- * Each size class maintains various freelists and zspages are assigned
- * to one of these freelists based on the number of live objects they
- * have. This functions inserts the given zspage into the freelist
- * identified by <class, fullness_group>.
+ * This function adds the given zspage to the fullness list identified
+ * by <class, fullness_group>.
*/
static void insert_zspage(struct size_class *class,
struct zspage *zspage,
enum fullness_group fullness)
{
- struct zspage *head;
-
class_stat_inc(class, fullness, 1);
- head = list_first_entry_or_null(&class->fullness_list[fullness],
- struct zspage, list);
- /*
- * We want to see more ZS_FULL pages and less almost empty/full.
- * Put pages with higher ->inuse first.
- */
- if (head && get_zspage_inuse(zspage) < get_zspage_inuse(head))
- list_add(&zspage->list, &head->list);
- else
- list_add(&zspage->list, &class->fullness_list[fullness]);
+ list_add(&zspage->list, &class->fullness_list[fullness]);
}
/*
- * This function removes the given zspage from the freelist identified
+ * This function removes the given zspage from the fullness list identified
* by <class, fullness_group>.
*/
static void remove_zspage(struct size_class *class,
This optimization has no effect. It only ensures that when a zspage was added to its corresponding fullness list, its "inuse" counter was higher or lower than the "inuse" counter of the zspage at the head of the list. The intention was to keep busy zspages at the head, so they could be filled up and moved to the ZS_FULL fullness group more quickly. However, this doesn't work as the "inuse" counter of a zspage can be modified by obj_free() but the zspage may still belong to the same fullness list. So, fix_fullness_group() won't change the zspage's position in relation to the head's "inuse" counter, leading to a largely random order of zspages within the fullness list. For instance, consider a printout of the "inuse" counters of the first 10 zspages in a class that holds 93 objects per zspage: ZS_ALMOST_EMPTY: 36 67 68 64 35 54 63 52 As we can see the zspage with the lowest "inuse" counter is actually the head of the fullness list. Remove this pointless "optimisation". Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> --- mm/zsmalloc.c | 21 ++++----------------- 1 file changed, 4 insertions(+), 17 deletions(-)