mm/vmalloc: allow to set node and align in vrealloc

Patch series "support large align and nid in Rust allocators", v15.

The series provides the ability for Rust allocators to set NUMA node and
large alignment.

This patch (of 4):

Reimplement vrealloc() to be able to set node and alignment should a user
need to do so.  Rename the function to vrealloc_node_align() to better
match what it actually does now and introduce macros for vrealloc() and
friends for backward compatibility.

With that change we also provide the ability for the Rust part of the
kernel to set node and alignment in its allocations.

Link: https://lkml.kernel.org/r/20250806124034.1724515-1-vitaly.wool@konsulko.se
Link: https://lkml.kernel.org/r/20250806124108.1724561-1-vitaly.wool@konsulko.se
Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.se>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Jann Horn <jannh@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 2759dac6be44eab3c97c0df13cfaed13289458c6..eb54b7b3202f4f2bd9d5a076d3610ae7df575a26 100644 (file)
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -197,9 +197,15 @@ extern void *__vcalloc_noprof(size_t n, size_t size, gfp_t flags) __alloc_size(1
 extern void *vcalloc_noprof(size_t n, size_t size) __alloc_size(1, 2);
 #define vcalloc(...)           alloc_hooks(vcalloc_noprof(__VA_ARGS__))
 
-void * __must_check vrealloc_noprof(const void *p, size_t size, gfp_t flags)
-               __realloc_size(2);
-#define vrealloc(...)          alloc_hooks(vrealloc_noprof(__VA_ARGS__))
+void *__must_check vrealloc_node_align_noprof(const void *p, size_t size,
+               unsigned long align, gfp_t flags, int nid) __realloc_size(2);
+#define vrealloc_node_noprof(_p, _s, _f, _nid) \
+       vrealloc_node_align_noprof(_p, _s, 1, _f, _nid)
+#define vrealloc_noprof(_p, _s, _f)            \
+       vrealloc_node_align_noprof(_p, _s, 1, _f, NUMA_NO_NODE)
+#define vrealloc_node_align(...)               alloc_hooks(vrealloc_node_align_noprof(__VA_ARGS__))
+#define vrealloc_node(...)                     alloc_hooks(vrealloc_node_noprof(__VA_ARGS__))
+#define vrealloc(...)                          alloc_hooks(vrealloc_noprof(__VA_ARGS__))
 
 extern void vfree(const void *addr);
 extern void vfree_atomic(const void *addr);

diff --git a/mm/nommu.c b/mm/nommu.c
index 8b819fafd57bfba163de0eadeea60d9296079c27..6fff462f90d38298f6833a98637eb65cbb9457c5 100644 (file)
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -119,7 +119,8 @@ void *__vmalloc_noprof(unsigned long size, gfp_t gfp_mask)
 }
 EXPORT_SYMBOL(__vmalloc_noprof);
 
-void *vrealloc_noprof(const void *p, size_t size, gfp_t flags)
+void *vrealloc_node_align_noprof(const void *p, size_t size, unsigned long align,
+                                gfp_t flags, int node)
 {
        return krealloc_noprof(p, size, (flags | __GFP_COMP) & ~__GFP_HIGHMEM);
 }

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 5edd536ba9d2a540491884b6def1728bbe4dc6df..8292735383e8aba112014dbbe608511a8642274d 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -4089,19 +4089,29 @@ void *vzalloc_node_noprof(unsigned long size, int node)
 EXPORT_SYMBOL(vzalloc_node_noprof);
 
 /**
- * vrealloc - reallocate virtually contiguous memory; contents remain unchanged
+ * vrealloc_node_align_noprof - reallocate virtually contiguous memory; contents
+ * remain unchanged
  * @p: object to reallocate memory for
  * @size: the size to reallocate
+ * @align: requested alignment
  * @flags: the flags for the page level allocator
+ * @nid: node number of the target node
+ *
+ * If @p is %NULL, vrealloc_XXX() behaves exactly like vmalloc_XXX(). If @size
+ * is 0 and @p is not a %NULL pointer, the object pointed to is freed.
  *
- * If @p is %NULL, vrealloc() behaves exactly like vmalloc(). If @size is 0 and
- * @p is not a %NULL pointer, the object pointed to is freed.
+ * If the caller wants the new memory to be on specific node *only*,
+ * __GFP_THISNODE flag should be set, otherwise the function will try to avoid
+ * reallocation and possibly disregard the specified @nid.
  *
  * If __GFP_ZERO logic is requested, callers must ensure that, starting with the
  * initial memory allocation, every subsequent call to this API for the same
  * memory allocation is flagged with __GFP_ZERO. Otherwise, it is possible that
  * __GFP_ZERO is not fully honored by this API.
  *
+ * Requesting an alignment that is bigger than the alignment of the existing
+ * allocation will fail.
+ *
  * In any case, the contents of the object pointed to are preserved up to the
  * lesser of the new and old sizes.
  *
@@ -4111,7 +4121,8 @@ EXPORT_SYMBOL(vzalloc_node_noprof);
  * Return: pointer to the allocated memory; %NULL if @size is zero or in case of
  *         failure
  */
-void *vrealloc_noprof(const void *p, size_t size, gfp_t flags)
+void *vrealloc_node_align_noprof(const void *p, size_t size, unsigned long align,
+                                gfp_t flags, int nid)
 {
        struct vm_struct *vm = NULL;
        size_t alloced_size = 0;
@@ -4135,6 +4146,12 @@ void *vrealloc_noprof(const void *p, size_t size, gfp_t flags)
                if (WARN(alloced_size < old_size,
                         "vrealloc() has mismatched area vs requested sizes (%p)\n", p))
                        return NULL;
+               if (WARN(!IS_ALIGNED((unsigned long)p, align),
+                        "will not reallocate with a bigger alignment (0x%lx)\n", align))
+                       return NULL;
+               if (unlikely(flags & __GFP_THISNODE) && nid != NUMA_NO_NODE &&
+                            nid != page_to_nid(vmalloc_to_page(p)))
+                       goto need_realloc;
        }
 
        /*
@@ -4165,8 +4182,10 @@ void *vrealloc_noprof(const void *p, size_t size, gfp_t flags)
                return (void *)p;
        }
 
+need_realloc:
        /* TODO: Grow the vm_area, i.e. allocate and map additional pages. */
-       n = __vmalloc_noprof(size, flags);
+       n = __vmalloc_node_noprof(size, align, flags, nid, __builtin_return_address(0));
+
        if (!n)
                return NULL;