mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab

These functions sit at the boundary to page allocator. Also use folio
internally to avoid extra compound_head() when dealing with page flags.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

diff --git a/mm/slab.c b/mm/slab.c
index 38fcd3f496df061a4bb91edcdf3b9002a3226dd7..dc9eb4a8f8695a8462550c448b3c7ac924202df8 100644 (file)
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1367,57 +1367,60 @@ slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
  * did not request dmaable memory, we might get it, but that
  * would be relatively rare and ignorable.
  */
-static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
+static struct slab *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
                                                                int nodeid)
 {
-       struct page *page;
+       struct folio *folio;
+       struct slab *slab;
 
        flags |= cachep->allocflags;
 
-       page = __alloc_pages_node(nodeid, flags, cachep->gfporder);
-       if (!page) {
+       folio = (struct folio *) __alloc_pages_node(nodeid, flags, cachep->gfporder);
+       if (!folio) {
                slab_out_of_memory(cachep, flags, nodeid);
                return NULL;
        }
 
-       account_slab(page_slab(page), cachep->gfporder, cachep, flags);
-       __SetPageSlab(page);
+       slab = folio_slab(folio);
+
+       account_slab(slab, cachep->gfporder, cachep, flags);
+       __folio_set_slab(folio);
        /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
-       if (sk_memalloc_socks() && page_is_pfmemalloc(page))
-               SetPageSlabPfmemalloc(page);
+       if (sk_memalloc_socks() && page_is_pfmemalloc(folio_page(folio, 0)))
+               slab_set_pfmemalloc(slab);
 
-       return page;
+       return slab;
 }
 
 /*
  * Interface to system's page release.
  */
-static void kmem_freepages(struct kmem_cache *cachep, struct page *page)
+static void kmem_freepages(struct kmem_cache *cachep, struct slab *slab)
 {
        int order = cachep->gfporder;
+       struct folio *folio = slab_folio(slab);
 
-       BUG_ON(!PageSlab(page));
-       __ClearPageSlabPfmemalloc(page);
-       __ClearPageSlab(page);
-       page_mapcount_reset(page);
-       /* In union with page->mapping where page allocator expects NULL */
-       page->slab_cache = NULL;
+       BUG_ON(!folio_test_slab(folio));
+       __slab_clear_pfmemalloc(slab);
+       __folio_clear_slab(folio);
+       page_mapcount_reset(folio_page(folio, 0));
+       folio->mapping = NULL;
 
        if (current->reclaim_state)
                current->reclaim_state->reclaimed_slab += 1 << order;
-       unaccount_slab(page_slab(page), order, cachep);
-       __free_pages(page, order);
+       unaccount_slab(slab, order, cachep);
+       __free_pages(folio_page(folio, 0), order);
 }
 
 static void kmem_rcu_free(struct rcu_head *head)
 {
        struct kmem_cache *cachep;
-       struct page *page;
+       struct slab *slab;
 
-       page = container_of(head, struct page, rcu_head);
-       cachep = page->slab_cache;
+       slab = container_of(head, struct slab, rcu_head);
+       cachep = slab->slab_cache;
 
-       kmem_freepages(cachep, page);
+       kmem_freepages(cachep, slab);
 }
 
 #if DEBUG
@@ -1624,7 +1627,7 @@ static void slab_destroy(struct kmem_cache *cachep, struct page *page)
        if (unlikely(cachep->flags & SLAB_TYPESAFE_BY_RCU))
                call_rcu(&page->rcu_head, kmem_rcu_free);
        else
-               kmem_freepages(cachep, page);
+               kmem_freepages(cachep, page_slab(page));
 
        /*
         * From now on, we don't use freelist
@@ -2578,7 +2581,7 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
         * Get mem for the objs.  Attempt to allocate a physical page from
         * 'nodeid'.
         */
-       page = kmem_getpages(cachep, local_flags, nodeid);
+       page = slab_page(kmem_getpages(cachep, local_flags, nodeid));
        if (!page)
                goto failed;
 
@@ -2620,7 +2623,7 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
        return page;
 
 opps1:
-       kmem_freepages(cachep, page);
+       kmem_freepages(cachep, page_slab(page));
 failed:
        if (gfpflags_allow_blocking(local_flags))
                local_irq_disable();