1 files changed, 402 insertions, 0 deletions
diff --git a/src/chunk_swap.c b/src/chunk_swap.c
new file mode 100644
index 0000000..cb25ae0
--- /dev/null
+++ b/src/chunk_swap.c
@@ -0,0 +1,402 @@
+#define	JEMALLOC_CHUNK_SWAP_C_
+#include "jemalloc/internal/jemalloc_internal.h"
+#ifdef JEMALLOC_SWAP
+/******************************************************************************/
+/* Data. */
+
+malloc_mutex_t	swap_mtx;
+bool		swap_enabled;
+bool		swap_prezeroed;
+size_t		swap_nfds;
+int		*swap_fds;
+#ifdef JEMALLOC_STATS
+size_t		swap_avail;
+#endif
+
+/* Base address of the mmap()ed file(s). */
+static void	*swap_base;
+/* Current end of the space in use (<= swap_max). */
+static void	*swap_end;
+/* Absolute upper limit on file-backed addresses. */
+static void	*swap_max;
+
+/*
+ * Trees of chunks that were previously allocated (trees differ only in node
+ * ordering).  These are used when allocating chunks, in an attempt to re-use
+ * address space.  Depending on function, different tree orderings are needed,
+ * which is why there are two trees with the same contents.
+ */
+static extent_tree_t	swap_chunks_szad;
+static extent_tree_t	swap_chunks_ad;
+
+/******************************************************************************/
+/* Function prototypes for non-inline static functions. */
+
+static void	*chunk_recycle_swap(size_t size, bool *zero);
+static extent_node_t *chunk_dealloc_swap_record(void *chunk, size_t size);
+
+/******************************************************************************/
+
+static void *
+chunk_recycle_swap(size_t size, bool *zero)
+{
+	extent_node_t *node, key;
+
+	key.addr = NULL;
+	key.size = size;
+	malloc_mutex_lock(&swap_mtx);
+	node = extent_tree_szad_nsearch(&swap_chunks_szad, &key);
+	if (node != NULL) {
+		void *ret = node->addr;
+
+		/* Remove node from the tree. */
+		extent_tree_szad_remove(&swap_chunks_szad, node);
+		if (node->size == size) {
+			extent_tree_ad_remove(&swap_chunks_ad, node);
+			base_node_dealloc(node);
+		} else {
+			/*
+			 * Insert the remainder of node's address range as a
+			 * smaller chunk.  Its position within swap_chunks_ad
+			 * does not change.
+			 */
+			assert(node->size > size);
+			node->addr = (void *)((uintptr_t)node->addr + size);
+			node->size -= size;
+			extent_tree_szad_insert(&swap_chunks_szad, node);
+		}
+#ifdef JEMALLOC_STATS
+		swap_avail -= size;
+#endif
+		malloc_mutex_unlock(&swap_mtx);
+
+		if (*zero)
+			memset(ret, 0, size);
+		return (ret);
+	}
+	malloc_mutex_unlock(&swap_mtx);
+
+	return (NULL);
+}
+
+void *
+chunk_alloc_swap(size_t size, bool *zero)
+{
+	void *ret;
+
+	assert(swap_enabled);
+
+	ret = chunk_recycle_swap(size, zero);
+	if (ret != NULL)
+		return (ret);
+
+	malloc_mutex_lock(&swap_mtx);
+	if ((uintptr_t)swap_end + size <= (uintptr_t)swap_max) {
+		ret = swap_end;
+		swap_end = (void *)((uintptr_t)swap_end + size);
+#ifdef JEMALLOC_STATS
+		swap_avail -= size;
+#endif
+		malloc_mutex_unlock(&swap_mtx);
+
+		if (swap_prezeroed)
+			*zero = true;
+		else if (*zero)
+			memset(ret, 0, size);
+	} else {
+		malloc_mutex_unlock(&swap_mtx);
+		return (NULL);
+	}
+
+	return (ret);
+}
+
+static extent_node_t *
+chunk_dealloc_swap_record(void *chunk, size_t size)
+{
+	extent_node_t *xnode, *node, *prev, key;
+
+	xnode = NULL;
+	while (true) {
+		key.addr = (void *)((uintptr_t)chunk + size);
+		node = extent_tree_ad_nsearch(&swap_chunks_ad, &key);
+		/* Try to coalesce forward. */
+		if (node != NULL && node->addr == key.addr) {
+			/*
+			 * Coalesce chunk with the following address range.
+			 * This does not change the position within
+			 * swap_chunks_ad, so only remove/insert from/into
+			 * swap_chunks_szad.
+			 */
+			extent_tree_szad_remove(&swap_chunks_szad, node);
+			node->addr = chunk;
+			node->size += size;
+			extent_tree_szad_insert(&swap_chunks_szad, node);
+			break;
+		} else if (xnode == NULL) {
+			/*
+			 * It is possible that base_node_alloc() will cause a
+			 * new base chunk to be allocated, so take care not to
+			 * deadlock on swap_mtx, and recover if another thread
+			 * deallocates an adjacent chunk while this one is busy
+			 * allocating xnode.
+			 */
+			malloc_mutex_unlock(&swap_mtx);
+			xnode = base_node_alloc();
+			malloc_mutex_lock(&swap_mtx);
+			if (xnode == NULL)
+				return (NULL);
+		} else {
+			/* Coalescing forward failed, so insert a new node. */
+			node = xnode;
+			xnode = NULL;
+			node->addr = chunk;
+			node->size = size;
+			extent_tree_ad_insert(&swap_chunks_ad, node);
+			extent_tree_szad_insert(&swap_chunks_szad, node);
+			break;
+		}
+	}
+	/* Discard xnode if it ended up unused do to a race. */
+	if (xnode != NULL)
+		base_node_dealloc(xnode);
+
+	/* Try to coalesce backward. */
+	prev = extent_tree_ad_prev(&swap_chunks_ad, node);
+	if (prev != NULL && (void *)((uintptr_t)prev->addr + prev->size) ==
+	    chunk) {
+		/*
+		 * Coalesce chunk with the previous address range.  This does
+		 * not change the position within swap_chunks_ad, so only
+		 * remove/insert node from/into swap_chunks_szad.
+		 */
+		extent_tree_szad_remove(&swap_chunks_szad, prev);
+		extent_tree_ad_remove(&swap_chunks_ad, prev);
+
+		extent_tree_szad_remove(&swap_chunks_szad, node);
+		node->addr = prev->addr;
+		node->size += prev->size;
+		extent_tree_szad_insert(&swap_chunks_szad, node);
+
+		base_node_dealloc(prev);
+	}
+
+	return (node);
+}
+
+bool
+chunk_in_swap(void *chunk)
+{
+	bool ret;
+
+	assert(swap_enabled);
+
+	malloc_mutex_lock(&swap_mtx);
+	if ((uintptr_t)chunk >= (uintptr_t)swap_base
+	    && (uintptr_t)chunk < (uintptr_t)swap_max)
+		ret = true;
+	else
+		ret = false;
+	malloc_mutex_unlock(&swap_mtx);
+
+	return (ret);
+}
+
+bool
+chunk_dealloc_swap(void *chunk, size_t size)
+{
+	bool ret;
+
+	assert(swap_enabled);
+
+	malloc_mutex_lock(&swap_mtx);
+	if ((uintptr_t)chunk >= (uintptr_t)swap_base
+	    && (uintptr_t)chunk < (uintptr_t)swap_max) {
+		extent_node_t *node;
+
+		/* Try to coalesce with other unused chunks. */
+		node = chunk_dealloc_swap_record(chunk, size);
+		if (node != NULL) {
+			chunk = node->addr;
+			size = node->size;
+		}
+
+		/*
+		 * Try to shrink the in-use memory if this chunk is at the end
+		 * of the in-use memory.
+		 */
+		if ((void *)((uintptr_t)chunk + size) == swap_end) {
+			swap_end = (void *)((uintptr_t)swap_end - size);
+
+			if (node != NULL) {
+				extent_tree_szad_remove(&swap_chunks_szad,
+				    node);
+				extent_tree_ad_remove(&swap_chunks_ad, node);
+				base_node_dealloc(node);
+			}
+		} else
+			madvise(chunk, size, MADV_DONTNEED);
+
+#ifdef JEMALLOC_STATS
+		swap_avail += size;
+#endif
+		ret = false;
+		goto RETURN;
+	}
+
+	ret = true;
+RETURN:
+	malloc_mutex_unlock(&swap_mtx);
+	return (ret);
+}
+
+bool
+chunk_swap_enable(const int *fds, unsigned nfds, bool prezeroed)
+{
+	bool ret;
+	unsigned i;
+	off_t off;
+	void *vaddr;
+	size_t cumsize, voff;
+	size_t sizes[nfds];
+
+	malloc_mutex_lock(&swap_mtx);
+
+	/* Get file sizes. */
+	for (i = 0, cumsize = 0; i < nfds; i++) {
+		off = lseek(fds[i], 0, SEEK_END);
+		if (off == ((off_t)-1)) {
+			ret = true;
+			goto RETURN;
+		}
+		if (PAGE_CEILING(off) != off) {
+			/* Truncate to a multiple of the page size. */
+			off &= ~PAGE_MASK;
+			if (ftruncate(fds[i], off) != 0) {
+				ret = true;
+				goto RETURN;
+			}
+		}
+		sizes[i] = off;
+		if (cumsize + off < cumsize) {
+			/*
+			 * Cumulative file size is greater than the total
+			 * address space.  Bail out while it's still obvious
+			 * what the problem is.
+			 */
+			ret = true;
+			goto RETURN;
+		}
+		cumsize += off;
+	}
+
+	/* Round down to a multiple of the chunk size. */
+	cumsize &= ~chunksize_mask;
+	if (cumsize == 0) {
+		ret = true;
+		goto RETURN;
+	}
+
+	/*
+	 * Allocate a chunk-aligned region of anonymous memory, which will
+	 * be the final location for the memory-mapped files.
+	 */
+	vaddr = chunk_alloc_mmap_noreserve(cumsize);
+	if (vaddr == NULL) {
+		ret = true;
+		goto RETURN;
+	}
+
+	/* Overlay the files onto the anonymous mapping. */
+	for (i = 0, voff = 0; i < nfds; i++) {
+		void *addr = mmap((void *)((uintptr_t)vaddr + voff), sizes[i],
+		    PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, fds[i], 0);
+		if (addr == MAP_FAILED) {
+			char buf[BUFERROR_BUF];
+
+
+			buferror(errno, buf, sizeof(buf));
+			malloc_write(
+			    "<jemalloc>: Error in mmap(..., MAP_FIXED, ...): ");
+			malloc_write(buf);
+			malloc_write("\n");
+			if (opt_abort)
+				abort();
+			if (munmap(vaddr, voff) == -1) {
+				buferror(errno, buf, sizeof(buf));
+				malloc_write("<jemalloc>: Error in munmap(): ");
+				malloc_write(buf);
+				malloc_write("\n");
+			}
+			ret = true;
+			goto RETURN;
+		}
+		assert(addr == (void *)((uintptr_t)vaddr + voff));
+
+		/*
+		 * Tell the kernel that the mapping will be accessed randomly,
+		 * and that it should not gratuitously sync pages to the
+		 * filesystem.
+		 */
+#ifdef MADV_RANDOM
+		madvise(addr, sizes[i], MADV_RANDOM);
+#endif
+#ifdef MADV_NOSYNC
+		madvise(addr, sizes[i], MADV_NOSYNC);
+#endif
+
+		voff += sizes[i];
+	}
+
+	swap_prezeroed = prezeroed;
+	swap_base = vaddr;
+	swap_end = swap_base;
+	swap_max = (void *)((uintptr_t)vaddr + cumsize);
+
+	/* Copy the fds array for mallctl purposes. */
+	swap_fds = (int *)base_alloc(nfds * sizeof(int));
+	if (swap_fds == NULL) {
+		ret = true;
+		goto RETURN;
+	}
+	memcpy(swap_fds, fds, nfds * sizeof(int));
+	swap_nfds = nfds;
+
+#ifdef JEMALLOC_STATS
+	swap_avail = cumsize;
+#endif
+
+	swap_enabled = true;
+
+	ret = false;
+RETURN:
+	malloc_mutex_unlock(&swap_mtx);
+	return (ret);
+}
+
+bool
+chunk_swap_boot(void)
+{
+
+	if (malloc_mutex_init(&swap_mtx))
+		return (true);
+
+	swap_enabled = false;
+	swap_prezeroed = false; /* swap.* mallctl's depend on this. */
+	swap_nfds = 0;
+	swap_fds = NULL;
+#ifdef JEMALLOC_STATS
+	swap_avail = 0;
+#endif
+	swap_base = NULL;
+	swap_end = NULL;
+	swap_max = NULL;
+
+	extent_tree_szad_new(&swap_chunks_szad);
+	extent_tree_ad_new(&swap_chunks_ad);
+
+	return (false);
+}
+
+/******************************************************************************/
+#endif /* JEMALLOC_SWAP */