On Wed, Jul 29, 2009 at 01:54:58PM -0400, Lee Schermerhorn wrote: > [PATCH 1/4] hugetlb: rework hstate_next_node* functions > > Against: 2.6.31-rc3-mmotm-090716-1432 > atop the alloc_bootmem_huge_page() fix patch > [http://marc.info/?l=linux-mm&m=124775468226290&w=4] > > V2: > + cleaned up comments, removed some deemed unnecessary, > add some suggested by review > + removed check for !current in huge_mpol_nodes_allowed(). > + added 'current->comm' to warning message in huge_mpol_nodes_allowed(). > + added VM_BUG_ON() assertion in hugetlb.c next_node_allowed() to > catch out of range node id. > + add examples to patch description > > V3: > + factored this "cleanup" patch out of V2 patch 2/3 > + moved ahead of patch to add nodes_allowed mask to alloc funcs > as this patch is somewhat independent from using task mempolicy > to control huge page allocation and freeing. > > Modify the hstate_next_node* functions to allow them to be called to > obtain the "start_nid". Then, whereas prior to this patch we > unconditionally called hstate_next_node_to_{alloc|free}(), whether > or not we successfully allocated/freed a huge page on the node, > now we only call these functions on failure to alloc/free. > > Factor out the next_node_allowed() function to handle wrap at end > of node_online_map. In this version, the allowed nodes are all > of the online nodes. > > Signed-off-by: Lee Schermerhorn <lee.schermerhorn@xxxxxx> > Reviewed-by: Mel Gorman <mel@xxxxxxxxx> > mm/hugetlb.c | 70 +++++++++++++++++++++++++++++++++++++---------------------- > 1 file changed, 45 insertions(+), 25 deletions(-) > > Index: linux-2.6.31-rc3-mmotm-090716-1432/mm/hugetlb.c > =================================================================== > --- linux-2.6.31-rc3-mmotm-090716-1432.orig/mm/hugetlb.c 2009-07-22 15:42:46.000000000 -0400 > +++ linux-2.6.31-rc3-mmotm-090716-1432/mm/hugetlb.c 2009-07-22 15:42:48.000000000 -0400 > @@ -622,6 +622,20 @@ static struct page *alloc_fresh_huge_pag > } > > /* > + * common helper function for hstate_next_node_to_{alloc|free}. > + * return next node in node_online_map, wrapping at end. > + */ > +static int next_node_allowed(int nid) > +{ > + nid = next_node(nid, node_online_map); > + if (nid == MAX_NUMNODES) > + nid = first_node(node_online_map); > + VM_BUG_ON(nid >= MAX_NUMNODES); > + > + return nid; > +} > + > +/* > * Use a helper variable to find the next node and then > * copy it back to next_nid_to_alloc afterwards: > * otherwise there's a window in which a racer might > @@ -634,12 +648,12 @@ static struct page *alloc_fresh_huge_pag > */ > static int hstate_next_node_to_alloc(struct hstate *h) > { > - int next_nid; > - next_nid = next_node(h->next_nid_to_alloc, node_online_map); > - if (next_nid == MAX_NUMNODES) > - next_nid = first_node(node_online_map); > + int nid, next_nid; > + > + nid = h->next_nid_to_alloc; > + next_nid = next_node_allowed(nid); > h->next_nid_to_alloc = next_nid; > - return next_nid; > + return nid; > } > > static int alloc_fresh_huge_page(struct hstate *h) > @@ -649,15 +663,17 @@ static int alloc_fresh_huge_page(struct > int next_nid; > int ret = 0; > > - start_nid = h->next_nid_to_alloc; > + start_nid = hstate_next_node_to_alloc(h); > next_nid = start_nid; > > do { > page = alloc_fresh_huge_page_node(h, next_nid); > - if (page) > + if (page) { > ret = 1; > + break; > + } > next_nid = hstate_next_node_to_alloc(h); > - } while (!page && next_nid != start_nid); > + } while (next_nid != start_nid); > > if (ret) > count_vm_event(HTLB_BUDDY_PGALLOC); > @@ -668,17 +684,19 @@ static int alloc_fresh_huge_page(struct > } > > /* > - * helper for free_pool_huge_page() - find next node > - * from which to free a huge page > + * helper for free_pool_huge_page() - return the next node > + * from which to free a huge page. Advance the next node id > + * whether or not we find a free huge page to free so that the > + * next attempt to free addresses the next node. > */ > static int hstate_next_node_to_free(struct hstate *h) > { > - int next_nid; > - next_nid = next_node(h->next_nid_to_free, node_online_map); > - if (next_nid == MAX_NUMNODES) > - next_nid = first_node(node_online_map); > + int nid, next_nid; > + > + nid = h->next_nid_to_free; > + next_nid = next_node_allowed(nid); > h->next_nid_to_free = next_nid; > - return next_nid; > + return nid; > } > > /* > @@ -693,7 +711,7 @@ static int free_pool_huge_page(struct hs > int next_nid; > int ret = 0; > > - start_nid = h->next_nid_to_free; > + start_nid = hstate_next_node_to_free(h); > next_nid = start_nid; > > do { > @@ -715,9 +733,10 @@ static int free_pool_huge_page(struct hs > } > update_and_free_page(h, page); > ret = 1; > + break; > } > next_nid = hstate_next_node_to_free(h); > - } while (!ret && next_nid != start_nid); > + } while (next_nid != start_nid); > > return ret; > } > @@ -1028,10 +1047,9 @@ int __weak alloc_bootmem_huge_page(struc > void *addr; > > addr = __alloc_bootmem_node_nopanic( > - NODE_DATA(h->next_nid_to_alloc), > + NODE_DATA(hstate_next_node_to_alloc(h)), > huge_page_size(h), huge_page_size(h), 0); > > - hstate_next_node_to_alloc(h); > if (addr) { > /* > * Use the beginning of the huge page to store the > @@ -1167,29 +1185,31 @@ static int adjust_pool_surplus(struct hs > VM_BUG_ON(delta != -1 && delta != 1); > > if (delta < 0) > - start_nid = h->next_nid_to_alloc; > + start_nid = hstate_next_node_to_alloc(h); > else > - start_nid = h->next_nid_to_free; > + start_nid = hstate_next_node_to_free(h); > next_nid = start_nid; > > do { > int nid = next_nid; > if (delta < 0) { > - next_nid = hstate_next_node_to_alloc(h); > /* > * To shrink on this node, there must be a surplus page > */ > - if (!h->surplus_huge_pages_node[nid]) > + if (!h->surplus_huge_pages_node[nid]) { > + next_nid = hstate_next_node_to_alloc(h); > continue; > + } > } > if (delta > 0) { > - next_nid = hstate_next_node_to_free(h); > /* > * Surplus cannot exceed the total number of pages > */ > if (h->surplus_huge_pages_node[nid] >= > - h->nr_huge_pages_node[nid]) > + h->nr_huge_pages_node[nid]) { > + next_nid = hstate_next_node_to_free(h); > continue; > + } > } > > h->surplus_huge_pages += delta; > -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe from this list: send the line "unsubscribe linux-numa" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
