Initial version.

1 files changed, 641 insertions, 0 deletions

diff --git a/src/nxt_mem_pool.c b/src/nxt_mem_pool.c
new file mode 100644
index 00000000..0d4b5688
--- /dev/null
+++ b/src/nxt_mem_pool.c
@@ -0,0 +1,641 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ * Copyright (C) NGINX, Inc.
+ */
+
+#include <nxt_main.h>
+
+
+/*
+ * The pool allocator provides cheap allocation of small objects.
+ * The objects are allocated from larger preallocated chunks.
+ *
+ *   aligned and non-aligned allocations,
+ *   cache of reusable objects, lvlhsh-specific cache
+ *   eliminating align padding
+ *   data locality
+ *   freeing on pool destruction
+ *   freeing large allocations
+ */
+
+
+static void *nxt_mem_pool_align(nxt_mem_pool_t *mp, size_t alignment,
+    size_t size);
+static void *nxt_mem_pool_ext(nxt_mem_pool_t *mp, size_t size);
+static nxt_mem_pool_chunk_t *nxt_mem_pool_next_chunk(nxt_mem_pool_t *mp,
+    nxt_mem_pool_chunk_t *chunk);
+static nxt_mem_pool_chunk_t *nxt_mem_pool_chunk(nxt_mem_pool_t *mp);
+static void *nxt_mem_lvlhsh_alloc_chunk(nxt_mem_pool_cache_t *cache,
+    size_t size, nxt_uint_t nalloc);
+
+
+#if (NXT_DEBUG)
+
+static nxt_bool_t
+nxt_mem_pool_thread_is_invalid(nxt_mem_pool_t *mp)
+{
+    nxt_tid_t     tid;
+    nxt_thread_t  *thr;
+
+    thr = nxt_thread();
+    tid = nxt_thread_tid(thr);
+
+    if (nxt_slow_path(mp->tid != tid)) {
+
+        if (mp->pid == nxt_pid) {
+            nxt_log_alert(thr->log, "mem_pool locked by thread %PT", mp->tid);
+            nxt_abort();
+            return 1;
+        }
+
+        mp->pid = nxt_pid;
+        mp->tid = tid;
+    }
+
+    return 0;
+}
+
+
+/* SunC does not support C99 variadic macro with empty __VA_ARGS__. */
+
+#define                                                                       \
+nxt_mem_pool_thread_assert(mp)                                                \
+    if (nxt_mem_pool_thread_is_invalid(mp))                                   \
+        return
+
+
+#define                                                                       \
+nxt_mem_pool_thread_assert_return(mp, ret)                                    \
+    if (nxt_mem_pool_thread_is_invalid(mp))                                   \
+        return ret
+
+
+#else /* !(NXT_DEBUG) */
+
+#define                                                                       \
+nxt_mem_pool_thread_assert(mp)
+
+#define                                                                       \
+nxt_mem_pool_thread_assert_return(mp, ret)
+
+#endif
+
+
+nxt_mem_pool_t *
+nxt_mem_pool_create(size_t size)
+{
+    u_char          *p;
+    size_t          min_ext_size;
+    nxt_mem_pool_t  *mp;
+
+    mp = nxt_malloc(size);
+
+    if (nxt_fast_path(mp != NULL)) {
+
+        mp->chunk_size = (uint32_t) size;
+
+        min_ext_size = size - sizeof(nxt_mem_pool_t) + 1;
+        mp->min_ext_size = (uint32_t) nxt_min(min_ext_size,
+                                              NXT_MEM_POOL_MIN_EXT_SIZE);
+
+        nxt_malloc_usable_size(mp, size);
+
+        p = (u_char *) mp;
+
+        mp->chunk.free = p + sizeof(nxt_mem_pool_t);
+        mp->chunk.end = p + size;
+        mp->chunk.next = NULL;
+        mp->chunk.fails = 0;
+
+        mp->current = &mp->chunk;
+        mp->ext = NULL;
+        mp->cleanup = NULL;
+        mp->cache = NULL;
+
+        nxt_thread_log_debug("mem pool chunk size:%uz avail:%uz",
+                             size, mp->chunk.end - mp->chunk.free);
+
+        nxt_mem_pool_debug_lock(mp, nxt_thread_tid(NULL));
+    }
+
+    return mp;
+}
+
+
+void
+nxt_mem_pool_destroy(nxt_mem_pool_t *mp)
+{
+    nxt_mem_pool_ext_t      *ext;
+    nxt_mem_pool_chunk_t    *chunk, *next;
+    nxt_mem_pool_cleanup_t  *mpcl;
+
+    nxt_mem_pool_thread_assert(mp);
+
+    for (mpcl = mp->cleanup; mpcl != NULL; mpcl = mpcl->next) {
+        if (mpcl->handler != NULL) {
+            nxt_thread_log_debug("mem pool cleanup: %p", mpcl);
+            mpcl->handler(mpcl->data);
+        }
+    }
+
+    for (ext = mp->ext; ext != NULL; ext = ext->next) {
+        if (ext->data != NULL) {
+            nxt_free(ext->data);
+        }
+    }
+
+    chunk = &mp->chunk;
+
+    do {
+        nxt_thread_log_debug("mem pool chunk fails:%uD unused:%uz",
+                             chunk->fails, chunk->end - chunk->free);
+        next = chunk->next;
+        nxt_free(chunk);
+        chunk = next;
+
+    } while (chunk != NULL);
+}
+
+
+void *
+nxt_mem_align(nxt_mem_pool_t *mp, size_t alignment, size_t size)
+{
+    nxt_mem_pool_thread_assert_return(mp, NULL);
+
+    if (nxt_fast_path(size < mp->min_ext_size)) {
+        return nxt_mem_pool_align(mp, alignment, size);
+    }
+
+    return nxt_mem_pool_ext(mp, size);
+}
+
+
+void *
+nxt_mem_zalign(nxt_mem_pool_t *mp, size_t alignment, size_t size)
+{
+    void  *p;
+
+    p = nxt_mem_align(mp, alignment, size);
+
+    if (nxt_fast_path(p != NULL)) {
+        nxt_memzero(p, size);
+    }
+
+    return p;
+}
+
+
+/*
+ * Zero-filled aligned allocation, suitable for struct
+ * allocation without long double and SIMD values.
+ */
+
+void *
+nxt_mem_zalloc(nxt_mem_pool_t *mp, size_t size)
+{
+    void  *p;
+
+    p = nxt_mem_alloc(mp, size);
+
+    if (nxt_fast_path(p != NULL)) {
+        nxt_memzero(p, size);
+    }
+
+    return p;
+}
+
+
+void *
+nxt_mem_buf(nxt_mem_pool_t *mp, size_t *sizep, nxt_uint_t flags)
+{
+    u_char  *p;
+    size_t  size;
+
+    nxt_mem_pool_thread_assert_return(mp, NULL);
+
+    size = *sizep;
+
+    if (nxt_fast_path(size >= mp->min_ext_size)) {
+
+        nxt_malloc_cutback(flags & NXT_MEM_BUF_CUTBACK, size);
+
+        /* Windows only: try to minimize number of allocated pages. */
+        p = nxt_mem_pool_ext(mp, size);
+        if (p != NULL) {
+
+            if (flags & NXT_MEM_BUF_USABLE) {
+                nxt_malloc_usable_size(p, size);
+            }
+
+            *sizep = size;
+        }
+
+        return p;
+    }
+
+    return nxt_mem_pool_align(mp, NXT_ALIGNMENT, size);
+}
+
+
+/* Non-aligned allocation, suitable for string allocation. */
+
+void *
+nxt_mem_nalloc(nxt_mem_pool_t *mp, size_t size)
+{
+    u_char                *p;
+    nxt_mem_pool_chunk_t  *chunk;
+
+    nxt_mem_pool_thread_assert_return(mp, NULL);
+
+    if (nxt_slow_path(size >= mp->min_ext_size)) {
+        return nxt_mem_pool_ext(mp, size);
+    }
+
+    chunk = mp->current;
+
+    for ( ;; ) {
+        p = chunk->end - size;
+
+        if (nxt_fast_path(p >= chunk->free)) {
+            chunk->end = p;
+            return p;
+        }
+
+        chunk = nxt_mem_pool_next_chunk(mp, chunk);
+
+        if (nxt_slow_path(chunk == NULL)) {
+            return NULL;
+        }
+    }
+}
+
+
+/* An attempt to deallocate a large allocation outside pool. */
+
+nxt_int_t
+nxt_mem_free(nxt_mem_pool_t *mp, void *p)
+{
+    nxt_mem_pool_ext_t  *ext;
+
+    nxt_mem_pool_thread_assert_return(mp, NXT_DECLINED);
+
+    for (ext = mp->ext; ext != NULL; ext = ext->next) {
+
+        if (p == ext->data) {
+            nxt_free(ext->data);
+            ext->data = NULL;
+
+            return NXT_OK;
+        }
+    }
+
+    return NXT_DECLINED;
+}
+
+
+static void *
+nxt_mem_pool_ext(nxt_mem_pool_t *mp, size_t size)
+{
+    void                *p;
+    nxt_mem_pool_ext_t  *ext;
+
+    ext = nxt_mem_pool_align(mp, sizeof(void *), sizeof(nxt_mem_pool_ext_t));
+
+    if (nxt_fast_path(ext != NULL)) {
+        p = nxt_malloc(size);
+
+        if (nxt_fast_path(p != NULL)) {
+            ext->data = p;
+            ext->next = mp->ext;
+            mp->ext = ext;
+
+            return p;
+        }
+    }
+
+    return NULL;
+}
+
+
+static void *
+nxt_mem_pool_align(nxt_mem_pool_t *mp, size_t alignment, size_t size)
+{
+    u_char                *p, *f;
+    nxt_mem_pool_chunk_t  *chunk;
+
+    chunk = mp->current;
+
+    for ( ;; ) {
+
+        p = nxt_align_ptr(chunk->free, alignment);
+        f = p + size;
+
+        if (nxt_fast_path(f <= chunk->end)) {
+            chunk->free = f;
+            return p;
+        }
+
+        chunk = nxt_mem_pool_next_chunk(mp, chunk);
+
+        if (nxt_slow_path(chunk == NULL)) {
+            return NULL;
+        }
+    }
+}
+
+
+static nxt_mem_pool_chunk_t *
+nxt_mem_pool_next_chunk(nxt_mem_pool_t *mp, nxt_mem_pool_chunk_t *chunk)
+{
+    nxt_bool_t  full;
+
+    full = (chunk->free == chunk->end || chunk->fails++ > 10);
+
+    chunk = chunk->next;
+
+    if (chunk == NULL) {
+        chunk = nxt_mem_pool_chunk(mp);
+
+        if (nxt_slow_path(chunk == NULL)) {
+            return NULL;
+        }
+    }
+
+    if (full) {
+        mp->current = chunk;
+    }
+
+    return chunk;
+}
+
+
+static nxt_mem_pool_chunk_t *
+nxt_mem_pool_chunk(nxt_mem_pool_t *mp)
+{
+    u_char                *p;
+    size_t                size;
+    nxt_mem_pool_chunk_t  *ch, *chunk;
+
+    size = mp->chunk_size;
+
+    chunk = nxt_malloc(size);
+
+    if (nxt_fast_path(chunk != NULL)) {
+
+        nxt_malloc_usable_size(chunk, size);
+
+        p = (u_char *) chunk;
+
+        chunk->free = p + sizeof(nxt_mem_pool_chunk_t);
+        chunk->end = p + size;
+        chunk->next = NULL;
+        chunk->fails = 0;
+
+        for (ch = mp->current; ch->next; ch = ch->next) { /* void */ }
+
+        ch->next = chunk;
+    }
+
+    return chunk;
+}
+
+
+nxt_mem_pool_cleanup_t *
+nxt_mem_pool_cleanup(nxt_mem_pool_t *mp, size_t size)
+{
+    nxt_mem_pool_cleanup_t  *mpcl;
+
+    nxt_mem_pool_thread_assert_return(mp, NULL);
+
+    mpcl = nxt_mem_pool_align(mp, sizeof(void *),
+                              sizeof(nxt_mem_pool_cleanup_t));
+    if (nxt_fast_path(mpcl != NULL)) {
+
+        mpcl->handler = NULL;
+        mpcl->data = NULL;
+
+        if (size != 0) {
+            mpcl->data = nxt_mem_alloc(mp, size);
+            if (nxt_slow_path(mpcl->data == NULL)) {
+                return NULL;
+            }
+        }
+
+        mpcl->next = mp->cleanup;
+        mp->cleanup = mpcl;
+
+        nxt_thread_log_debug("mem pool cleanup add: %p", mpcl);
+    }
+
+    return mpcl;
+}
+
+
+/* Allocation of reusable object with specified size. */
+
+void *
+nxt_mem_cache_alloc0(nxt_mem_pool_t *mp, size_t size)
+{
+    void                  **pp;
+    nxt_mem_pool_cache_t  *cache;
+
+    nxt_mem_pool_thread_assert_return(mp, NULL);
+
+    for (cache = mp->cache; cache != NULL; cache = cache->next) {
+
+        if (cache->size == size && cache->nalloc == 0) {
+
+            if (cache->free != NULL) {
+                pp = cache->free;
+                cache->free = *pp;
+                return pp;
+            }
+
+            break;
+        }
+    }
+
+    return nxt_mem_alloc(mp, size);
+}
+
+
+void *
+nxt_mem_cache_zalloc0(nxt_mem_pool_t *mp, size_t size)
+{
+    void  *p;
+
+    p = nxt_mem_cache_alloc0(mp, size);
+
+    if (nxt_fast_path(p != NULL)) {
+        nxt_memzero(p, size);
+    }
+
+    return p;
+}
+
+
+/* Deallocation of reusable object with specified size. */
+
+void
+nxt_mem_cache_free0(nxt_mem_pool_t *mp, void *p, size_t size)
+{
+    void                  **pp;
+    nxt_mem_pool_cache_t  *cache, **pcache;
+
+    nxt_mem_pool_thread_assert(mp);
+
+    pp = p;
+
+    pcache = &mp->cache;
+    for (cache = mp->cache; cache != NULL; cache = cache->next) {
+
+        if (cache->size == size && cache->nalloc == 0) {
+            *pp = cache->free;
+            cache->free = p;
+            return;
+        }
+
+        pcache = &cache->next;
+    }
+
+    /* Non-lvlhash caches are created only on return. */
+
+    cache = nxt_mem_pool_align(mp, sizeof(void *),
+                               sizeof(nxt_mem_pool_cache_t));
+    if (nxt_fast_path(cache != NULL)) {
+        *pp = NULL;
+        cache->size = (uint32_t) size;
+        cache->nalloc = 0;
+        cache->free = p;
+        cache->next = NULL;
+        *pcache = cache;
+    }
+}
+
+
+/*
+ * lvlhsh requires allocations aligned to a size of the allocations.
+ * This is not issue for slab-like allocators, but glibc allocator may
+ * waste memory on such aligned allocations.  So nxt_mem_lvlhsh_alloc()
+ * allocates memory in chunks specified by the "nalloc" parameter
+ * except the first allocation.  The first lvlhsh allocation is a bucket
+ * allocation and it is enough for small hashes and for early stage
+ * of a hash.  By default lvlhsh uses 128-bytes buckets and levels.
+ * This allows to search up to 10 entries in one memory access and
+ * up to 160 entries in two memory accesses on 64-bit platform.
+ * And on 32-bit platform up to 15 entries and up to 480 entries
+ * respectively.
+ *
+ * After the bucket will be filled up with 10 64-bit entries or 15
+ * 32-bit entries, lvlhsh will expand it to a level and content
+ * of the first bucket will spread to the level's new buckets.
+ * Number of the new buckets may be up to 11 on 64-bit or 16 on 32-bit
+ * platforms.  It's better to allocate them together to eliminate
+ * wasting memory and CPU time.
+ *
+ * The "nalloc" should be 16 if bucket size is 128 bytes.
+ */
+
+
+/* Allocation of lvlhsh level or bucket with specified size. */
+
+void *
+nxt_mem_lvlhsh_alloc(void *ctx, size_t size, nxt_uint_t nalloc)
+{
+    void                  *p, **pp;
+    nxt_mem_pool_t        *mp;
+    nxt_mem_pool_cache_t  *cache;
+
+    mp = ctx;
+
+    nxt_mem_pool_thread_assert_return(mp, NULL);
+
+    for (cache = mp->cache; cache != NULL; cache = cache->next) {
+
+        if (cache->size == size && cache->nalloc != 0) {
+
+            if (cache->free != NULL) {
+                pp = cache->free;
+                cache->free = *pp;
+                return pp;
+            }
+
+            return nxt_mem_lvlhsh_alloc_chunk(cache, size, nalloc);
+        }
+    }
+
+    cache = nxt_mem_pool_align(mp, sizeof(void *),
+                               sizeof(nxt_mem_pool_cache_t));
+    if (nxt_fast_path(cache != NULL)) {
+
+        p = nxt_memalign(size, size);
+
+        if (nxt_fast_path(p != NULL)) {
+            cache->size = (uint32_t) size;
+            cache->nalloc = nalloc;
+            cache->free = NULL;
+            cache->next = mp->cache;
+            mp->cache = cache;
+            return p;
+        }
+    }
+
+    return NULL;
+}
+
+
+static void *
+nxt_mem_lvlhsh_alloc_chunk(nxt_mem_pool_cache_t *cache, size_t size,
+    nxt_uint_t nalloc)
+{
+    char    *m, *p, *end;
+    void    **pp;
+    size_t  n;
+
+    n = (nalloc == 0) ? 1 : nalloc;
+    n *= size;
+
+    m = nxt_memalign(size, n);
+
+    if (nxt_fast_path(m != NULL)) {
+
+        pp = &cache->free;
+        end = m + n;
+
+        for (p = m + size; p < end; p = p + size) {
+            *pp = p;
+            pp = (void **) p;
+        }
+
+        *pp = NULL;
+    }
+
+    return m;
+}
+
+
+/* Deallocation of lvlhsh level or bucket with specified size. */
+
+void
+nxt_mem_lvlhsh_free(void *ctx, void *p, size_t size)
+{
+    void                  **pp;
+    nxt_mem_pool_t        *mp;
+    nxt_mem_pool_cache_t  *cache;
+
+    mp = ctx;
+
+    nxt_mem_pool_thread_assert(mp);
+
+    pp = p;
+
+    for (cache = mp->cache; cache != NULL; cache = cache->next) {
+
+        if (cache->size == size && cache->nalloc != 0) {
+            *pp = cache->free;
+            cache->free = p;
+            return;
+        }
+    }
+}