On Fri, Oct 19, 2012 at 2:46 AM, <wency@xxxxxxxxxxxxxx> wrote: > From: Wen Congyang <wency@xxxxxxxxxxxxxx> > > NR_FREE_PAGES will be wrong after offlining pages. We add/dec NR_FREE_PAGES > like this now: > 1. mova all pages in buddy system to MIGRATE_ISOLATE, and dec NR_FREE_PAGES move? > 2. don't add NR_FREE_PAGES when it is freed and the migratetype is MIGRATE_ISOLATE > 3. dec NR_FREE_PAGES when offlining isolated pages. > 4. add NR_FREE_PAGES when undoing isolate pages. > > When we come to step 3, all pages are in MIGRATE_ISOLATE list, and NR_FREE_PAGES > are right. When we come to step4, all pages are not in buddy system, so we don't > change NR_FREE_PAGES in this step, but we change NR_FREE_PAGES in step3. So > NR_FREE_PAGES is wrong after offlining pages. So there is no need to change > NR_FREE_PAGES in step3. Sorry, I don't understand this two paragraph. Can you please elaborate more? and one more trivial question: why do we need to call undo_isolate_page_range() from __offline_pages()? > > This patch also fixs a problem in step2: if the migratetype is MIGRATE_ISOLATE, > we should not add NR_FRR_PAGES when we remove pages from pcppages. Why drain_all_pages doesn't work? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>