(Sorry for repeated mail, I forgot to Cc the list..) On Wednesday 22 June 2011 06:38:00 you wrote: > * Nai Xia (nai.xia@xxxxxxxxx) wrote: > > Introduced ksm_page_changed() to reference the dirty bit of a pte. We clear > > the dirty bit for each pte scanned but don't flush the tlb. For a huge page, > > if one of the subpage has changed, we try to skip the whole huge page > > assuming(this is true by now) that ksmd linearly scans the address space. > > This doesn't build w/ kvm as a module. I think it's because of the name-error of a related kvm patch, which I only sent in a same email thread. http://marc.info/?l=linux-mm&m=130866318804277&w=2 The patch split is not clean...I'll redo it. > > > A NEW_FLAG is also introduced as a status of rmap_item to make ksmd scan > > more aggressively for new VMAs - only skip the pages considered to be volatile > > by the dirty bits. This can be enabled/disabled through KSM's sysfs interface. > > This seems like it should be separated out. And while it might be useful > to enable/disable for testing, I don't think it's worth supporting for > the long term. Would also be useful to see the value of this flag. I think it maybe useful for uses who want to turn on/off this scan policy explicitly according to their working sets? > > > @@ -454,7 +468,7 @@ static void remove_node_from_stable_tree(struct stable_node *stable_node) > > else > > ksm_pages_shared--; > > put_anon_vma(rmap_item->anon_vma); > > - rmap_item->address &= PAGE_MASK; > > + rmap_item->address &= ~STABLE_FLAG; > > cond_resched(); > > } > > > > @@ -542,7 +556,7 @@ static void remove_rmap_item_from_tree(struct rmap_item *rmap_item) > > ksm_pages_shared--; > > > > put_anon_vma(rmap_item->anon_vma); > > - rmap_item->address &= PAGE_MASK; > > + rmap_item->address &= ~STABLE_FLAG; > > > > } else if (rmap_item->address & UNSTABLE_FLAG) { > > unsigned char age; > > @@ -554,12 +568,14 @@ static void remove_rmap_item_from_tree(struct rmap_item *rmap_item) > > * than left over from before. > > */ > > age = (unsigned char)(ksm_scan.seqnr - rmap_item->address); > > - BUG_ON(age > 1); > > + BUG_ON (age > 1); > > No need to add space after BUG_ON() there > > > + > > if (!age) > > rb_erase(&rmap_item->node, &root_unstable_tree); > > > > ksm_pages_unshared--; > > - rmap_item->address &= PAGE_MASK; > > + rmap_item->address &= ~UNSTABLE_FLAG; > > + rmap_item->address &= ~SEQNR_MASK; > > None of these changes are needed AFAICT. &= PAGE_MASK clears all > relevant bits. How could it be in a tree, have NEW_FLAG set, and > while removing from tree want to preserve NEW_FLAG? You are right, it's meaningless to preserve NEW_FLAG after it goes through the trees. I'll revert the lines. Thanks! Nai > > thanks, > -chris > -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>