xnu-1228.3.13.tar.gz

[apple/xnu.git] / osfmk / vm / vm_purgeable.c

diff --git a/osfmk/vm/vm_purgeable.c b/osfmk/vm/vm_purgeable.c
index df1f3f810b7bcf307937fa66a97875672e5c5713..dfd80266f956420d3e8592214e335f8297a4e4f6 100644 (file)
--- a/osfmk/vm/vm_purgeable.c
+++ b/osfmk/vm/vm_purgeable.c
@@ -33,9 +33,9 @@ struct token {
 
 struct token    tokens[MAX_VOLATILE];
 
-token_idx_t     token_free_idx = 0;    /* head of free queue */
-token_cnt_t     token_init_count = 1;  /* token 0 is reserved!! */
-token_cnt_t     token_new_pagecount = 0;       /* count of pages that will
+token_idx_t     token_free_idx = 0;            /* head of free queue */
+token_idx_t     token_init_idx = 1;            /* token 0 is reserved!! */
+int32_t                token_new_pagecount = 0;        /* count of pages that will
                                                 * be added onto token queue */
 
 int             available_for_purge = 0;       /* increase when ripe token
@@ -96,9 +96,9 @@ vm_purgeable_token_add(purgeable_q_t queue)
        token_idx_t     token;
        enum purgeable_q_type i;
 
-       if (token_init_count < MAX_VOLATILE) {  /* lazy token array init */
-               token = token_init_count;
-               token_init_count++;
+       if (token_init_idx < MAX_VOLATILE) {    /* lazy token array init */
+               token = token_init_idx;
+               token_init_idx++;
        } else if (token_free_idx) {
                token = token_free_idx;
                token_free_idx = tokens[token_free_idx].next;
@@ -111,9 +111,10 @@ vm_purgeable_token_add(purgeable_q_t queue)
         * obsolete
         */
        for (i = PURGEABLE_Q_TYPE_FIFO; i < PURGEABLE_Q_TYPE_MAX; i++) {
-               purgeable_queues[i].new_pages += token_new_pagecount;
-               assert(purgeable_queues[i].new_pages >= 0);
-               assert((uint64_t) (purgeable_queues[i].new_pages) <= TOKEN_COUNT_MAX);
+               int64_t pages = purgeable_queues[i].new_pages += token_new_pagecount;
+               assert(pages >= 0);
+               assert(pages <= TOKEN_COUNT_MAX);
+               purgeable_queues[i].new_pages=pages;
        }
        token_new_pagecount = 0;
 
@@ -235,6 +236,20 @@ vm_purgeable_token_delete_first(purgeable_q_t queue)
 void
 vm_purgeable_q_advance_all(uint32_t num_pages)
 {
+       /* check queue counters - if they get really large, scale them back.
+        * They tend to get that large when there is no purgeable queue action */
+       int i;
+       if(token_new_pagecount > (INT32_MAX >> 1))      /* a system idling years might get there */
+       {
+               for (i = PURGEABLE_Q_TYPE_FIFO; i < PURGEABLE_Q_TYPE_MAX; i++) {
+                       int64_t pages = purgeable_queues[i].new_pages += token_new_pagecount;
+                       assert(pages >= 0);
+                       assert(pages <= TOKEN_COUNT_MAX);
+                       purgeable_queues[i].new_pages=pages;
+               }
+               token_new_pagecount = 0;
+       }
+       
        /*
         * don't need to advance obsolete queue - all items are ripe there,
         * always