Hello Mel Gorman,
The patch 1688e2896de4: "mm, compaction: round-robin the order while
searching the free lists for a target" from Jan 8, 2019, leads to the
following static checker warning:
mm/compaction.c:1252 next_search_order()
warn: impossible condition '(cc->search_order < 0) => (0-u16max < 0)'
mm/compaction.c
1243 static int next_search_order(struct compact_control *cc, int order)
1244 {
1245 order--;
1246 if (order < 0)
1247 order = cc->order - 1;
1248
1249 /* Search wrapped around? */
1250 if (order == cc->search_order) {
1251 cc->search_order--;
--> 1252 if (cc->search_order < 0)
^^^^^^^^^^^^^^^^^^^^
u16 can't be negative.
1253 cc->search_order = cc->order - 1;
1254 return -1;
1255 }
1256
1257 return order;
1258 }
regards,
dan carpenter
