On Tue, 2 Jan 2024, Gang Li wrote:
> The parallelization of hugetlb allocation leads to errors when sharing
> h->next_nid_to_alloc across different threads. To address this, it's
> necessary to assign a separate next_nid_to_alloc for each thread.
>
> Consequently, the hstate_next_node_to_alloc and for_each_node_mask_to_alloc
> have been modified to directly accept a *next_nid_to_alloc parameter,
> ensuring thread-specific allocation and avoiding concurrent access issues.
>
> Signed-off-by: Gang Li <gang.li@xxxxxxxxx>
> ---
> This patch seems not elegant, but I can't come up with anything better.
> Any suggestions will be highly appreciated!
Same error as v2:
mm/hugetlb.c:3315:53: warning: variable 'node' is used uninitialized whenever '&&' condition is false [-Wsometimes-uninitialized]
for_each_node_mask_to_alloc(&h->next_nid_to_alloc, nr_nodes, node, &node_states[N_MEMORY]) {
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mm/hugetlb.c:1501:3: note: expanded from macro 'for_each_node_mask_to_alloc'
nr_nodes > 0 && \
^~~~~~~~~~~~
mm/hugetlb.c:3342:38: note: uninitialized use occurs here
list_add(&m->list, &huge_boot_pages[node]);
^~~~
mm/hugetlb.c:3315:53: note: remove the '&&' if its condition is always true
for_each_node_mask_to_alloc(&h->next_nid_to_alloc, nr_nodes, node, &node_states[N_MEMORY]) {
^
mm/hugetlb.c:3310:7: warning: variable 'node' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
if (!m)
^~
mm/hugetlb.c:3342:38: note: uninitialized use occurs here
list_add(&m->list, &huge_boot_pages[node]);
^~~~
mm/hugetlb.c:3310:3: note: remove the 'if' if its condition is always true
if (!m)
^~~~~~~
mm/hugetlb.c:3304:20: note: initialize the variable 'node' to silence this warning
int nr_nodes, node;
^
= 0
2 warnings generated.
> ---
> mm/hugetlb.c | 22 ++++++++++++----------
> 1 file changed, 12 insertions(+), 10 deletions(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 92448e747991d..a71bc1622b53b 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1464,15 +1464,15 @@ static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
> * next node from which to allocate, handling wrap at end of node
> * mask.
> */
> -static int hstate_next_node_to_alloc(struct hstate *h,
> +static int hstate_next_node_to_alloc(int *next_nid_to_alloc,
> nodemask_t *nodes_allowed)
> {
> int nid;
>
> VM_BUG_ON(!nodes_allowed);
>
> - nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
> - h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
> + nid = get_valid_node_allowed(*next_nid_to_alloc, nodes_allowed);
> + *next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
>
> return nid;
> }
> @@ -1495,10 +1495,10 @@ static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
> return nid;
> }
>
> -#define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
> +#define for_each_node_mask_to_alloc(next_nid_to_alloc, nr_nodes, node, mask) \
> for (nr_nodes = nodes_weight(*mask); \
> nr_nodes > 0 && \
> - ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
> + ((node = hstate_next_node_to_alloc(next_nid_to_alloc, mask)) || 1); \
> nr_nodes--)
>
> #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
> @@ -2350,12 +2350,13 @@ static void prep_and_add_allocated_folios(struct hstate *h,
> */
> static struct folio *alloc_pool_huge_folio(struct hstate *h,
> nodemask_t *nodes_allowed,
> - nodemask_t *node_alloc_noretry)
> + nodemask_t *node_alloc_noretry,
> + int *next_nid_to_alloc)
> {
> gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
> int nr_nodes, node;
>
> - for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
> + for_each_node_mask_to_alloc(next_nid_to_alloc, nr_nodes, node, nodes_allowed) {
> struct folio *folio;
>
> folio = only_alloc_fresh_hugetlb_folio(h, gfp_mask, node,
> @@ -3310,7 +3311,7 @@ int __alloc_bootmem_huge_page(struct hstate *h, int nid)
> goto found;
> }
> /* allocate from next node when distributing huge pages */
> - for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
> + for_each_node_mask_to_alloc(&h->next_nid_to_alloc, nr_nodes, node, &node_states[N_MEMORY]) {
> m = memblock_alloc_try_nid_raw(
> huge_page_size(h), huge_page_size(h),
> 0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
> @@ -3684,7 +3685,7 @@ static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
> VM_BUG_ON(delta != -1 && delta != 1);
>
> if (delta < 0) {
> - for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
> + for_each_node_mask_to_alloc(&h->next_nid_to_alloc, nr_nodes, node, nodes_allowed) {
> if (h->surplus_huge_pages_node[node])
> goto found;
> }
> @@ -3799,7 +3800,8 @@ static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
> cond_resched();
>
> folio = alloc_pool_huge_folio(h, nodes_allowed,
> - node_alloc_noretry);
> + node_alloc_noretry,
> + &h->next_nid_to_alloc);
> if (!folio) {
> prep_and_add_allocated_folios(h, &page_list);
> spin_lock_irq(&hugetlb_lock);
> --
> 2.20.1
>
>
