Class JEmalloc


  • public class JEmalloc
    extends java.lang.Object
    Native bindings to jemalloc.

    jemalloc is a general purpose malloc implementation that emphasizes fragmentation avoidance and scalable concurrency support. jemalloc first came into use as the FreeBSD libc allocator in 2005, and since then it has found its way into numerous applications that rely on its predictable behavior. In 2010 jemalloc development efforts broadened to include developer support features such as heap profiling, Valgrind integration, and extensive monitoring/tuning hooks. Modern jemalloc releases continue to be integrated back into FreeBSD, and therefore versatility remains critical. Ongoing development efforts trend toward making jemalloc among the best allocators for a broad range of demanding applications, and eliminating/mitigating weaknesses that have practical repercussions for real world applications.

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static class  JEmalloc.Functions
      Contains the function pointers loaded from the jemalloc SharedLibrary.
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static SharedLibrary getLibrary()
      Returns the jemalloc SharedLibrary.
      static java.nio.ByteBuffer je_aligned_alloc​(long alignment, long size)
      Allocates size bytes of memory such that the allocation's base address is an even multiple of alignment.
      static java.nio.ByteBuffer je_calloc​(long num, long size)
      Allocates space for num objects, each size bytes in length.
      static void je_dallocx​(java.nio.ByteBuffer ptr, int flags)
      Causes the memory referenced by ptr to be made available for future allocations.
      static void je_dallocx​(java.nio.DoubleBuffer ptr, int flags)
      Causes the memory referenced by ptr to be made available for future allocations.
      static void je_dallocx​(java.nio.FloatBuffer ptr, int flags)
      Causes the memory referenced by ptr to be made available for future allocations.
      static void je_dallocx​(java.nio.IntBuffer ptr, int flags)
      Causes the memory referenced by ptr to be made available for future allocations.
      static void je_dallocx​(java.nio.LongBuffer ptr, int flags)
      Causes the memory referenced by ptr to be made available for future allocations.
      static void je_dallocx​(java.nio.ShortBuffer ptr, int flags)
      Causes the memory referenced by ptr to be made available for future allocations.
      static void je_dallocx​(PointerBuffer ptr, int flags)
      Causes the memory referenced by ptr to be made available for future allocations.
      static void je_free​(java.nio.ByteBuffer ptr)
      Causes the allocated memory referenced by ptr to be made available for future allocations.
      static void je_free​(java.nio.DoubleBuffer ptr)
      Causes the allocated memory referenced by ptr to be made available for future allocations.
      static void je_free​(java.nio.FloatBuffer ptr)
      Causes the allocated memory referenced by ptr to be made available for future allocations.
      static void je_free​(java.nio.IntBuffer ptr)
      Causes the allocated memory referenced by ptr to be made available for future allocations.
      static void je_free​(java.nio.LongBuffer ptr)
      Causes the allocated memory referenced by ptr to be made available for future allocations.
      static void je_free​(java.nio.ShortBuffer ptr)
      Causes the allocated memory referenced by ptr to be made available for future allocations.
      static void je_free​(PointerBuffer ptr)
      Causes the allocated memory referenced by ptr to be made available for future allocations.
      static int je_mallctl​(java.lang.CharSequence name, java.nio.ByteBuffer oldp, PointerBuffer oldlenp, java.nio.ByteBuffer newp)
      Provides a general interface for introspecting the memory allocator, as well as setting modifiable parameters and triggering actions.
      static int je_mallctl​(java.nio.ByteBuffer name, java.nio.ByteBuffer oldp, PointerBuffer oldlenp, java.nio.ByteBuffer newp)
      Provides a general interface for introspecting the memory allocator, as well as setting modifiable parameters and triggering actions.
      static int je_mallctlbymib​(PointerBuffer mib, java.nio.ByteBuffer oldp, PointerBuffer oldlenp, java.nio.ByteBuffer newp)
      Similar to mallctl, but uses MIBs instead of names.
      static int je_mallctlnametomib​(java.lang.CharSequence name, PointerBuffer mibp, PointerBuffer miblenp)
      Provides a way to avoid repeated name lookups for applications that repeatedly query the same portion of the namespace, by translating a name to a “Management Information Base” (MIB) that can be passed repeatedly to mallctlbymib.
      static int je_mallctlnametomib​(java.nio.ByteBuffer name, PointerBuffer mibp, PointerBuffer miblenp)
      Provides a way to avoid repeated name lookups for applications that repeatedly query the same portion of the namespace, by translating a name to a “Management Information Base” (MIB) that can be passed repeatedly to mallctlbymib.
      static java.nio.ByteBuffer je_malloc​(long size)
      Allocates size bytes of uninitialized memory.
      static PointerBuffer je_malloc_message()
      Returns the je_malloc_message variable.
      static void je_malloc_stats_print​(MallocMessageCallbackI write_cb, long cbopaque, java.lang.CharSequence opts)
      Writes human-readable summary statistics via the write_cb callback function pointer and cbopaque data passed to write_cb, or malloc_message() if write_cb is NULL.
      static void je_malloc_stats_print​(MallocMessageCallbackI write_cb, long cbopaque, java.nio.ByteBuffer opts)
      Writes human-readable summary statistics via the write_cb callback function pointer and cbopaque data passed to write_cb, or malloc_message() if write_cb is NULL.
      static long je_malloc_usable_size​(java.nio.ByteBuffer ptr)
      Returns the usable size of the allocation pointed to by ptr.
      static java.nio.ByteBuffer je_mallocx​(long size, int flags)
      Allocates at least size bytes of memory, and returns a pointer to the base address of the allocation.
      static java.nio.ByteBuffer je_nallocx​(long size, int flags)
      Allocates no memory, but it performs the same size computation as the mallocx function, and returns the real size of the allocation that would result from the equivalent mallocx() function call.
      static int je_posix_memalign​(PointerBuffer memptr, long alignment, long size)
      Allocates size bytes of memory such that the allocation's base address is an even multiple of alignment, and returns the allocation in the value pointed to by memptr.
      static java.nio.ByteBuffer je_rallocx​(java.nio.ByteBuffer ptr, long size, int flags)
      Resizes the allocation at ptr to be at least size bytes, and returns a pointer to the base address of the resulting allocation, which may or may not have moved from its original location.
      static java.nio.ByteBuffer je_realloc​(java.nio.ByteBuffer ptr, long size)
      Changes the size of the previously allocated memory referenced by ptr to size bytes.
      static long je_sallocx​(java.nio.ByteBuffer ptr, int flags)
      Returns the real size of the allocation at ptr.
      static void je_sdallocx​(java.nio.ByteBuffer ptr, int flags)
      Sized version of dallocx.
      static void je_sdallocx​(java.nio.DoubleBuffer ptr, int flags)
      Sized version of dallocx.
      static void je_sdallocx​(java.nio.FloatBuffer ptr, int flags)
      Sized version of dallocx.
      static void je_sdallocx​(java.nio.IntBuffer ptr, int flags)
      Sized version of dallocx.
      static void je_sdallocx​(java.nio.LongBuffer ptr, int flags)
      Sized version of dallocx.
      static void je_sdallocx​(java.nio.ShortBuffer ptr, int flags)
      Sized version of dallocx.
      static void je_sdallocx​(PointerBuffer ptr, int flags)
      Sized version of dallocx.
      static long je_xallocx​(java.nio.ByteBuffer ptr, long size, long extra, int flags)
      Resizes the allocation at ptr in place to be at least size bytes, and returns the real size of the allocation.
      static int MALLOCX_ALIGN​(int a)
      Align the memory allocation to start at an address that is a multiple of a, where a is a power of two.
      static int MALLOCX_ARENA​(int a)
      Use the arena specified by the index a (and by necessity bypass the thread cache).
      static int MALLOCX_LG_ALIGN​(int la)
      Align the memory allocation to start at an address that is a multiple of (1 << la).
      static int MALLOCX_TCACHE​(int tc)
      Use the thread-specific cache (tcache) specified by the identifier tc, which must have been acquired via the tcache.create mallctl.
      static long nje_aligned_alloc​(long alignment, long size)
      Unsafe version of: aligned_alloc
      static long nje_calloc​(long num, long size)
      Unsafe version of: calloc
      static void nje_dallocx​(long ptr, int flags)
      Unsafe version of: dallocx
      static void nje_free​(long ptr)
      Unsafe version of: free
      static int nje_mallctl​(long name, long oldp, long oldlenp, long newp, long newlen)
      Unsafe version of: mallctl
      static int nje_mallctlbymib​(long mib, long miblen, long oldp, long oldlenp, long newp, long newlen)
      Unsafe version of: mallctlbymib
      static int nje_mallctlnametomib​(long name, long mibp, long miblenp)
      Unsafe version of: mallctlnametomib
      static long nje_malloc​(long size)
      Unsafe version of: malloc
      static void nje_malloc_stats_print​(long write_cb, long cbopaque, long opts)
      Unsafe version of: malloc_stats_print
      static long nje_malloc_usable_size​(long ptr)
      Unsafe version of: malloc_usable_size
      static long nje_mallocx​(long size, int flags)
      Unsafe version of: mallocx
      static long nje_nallocx​(long size, int flags)
      Unsafe version of: nallocx
      static int nje_posix_memalign​(long memptr, long alignment, long size)
      Unsafe version of: posix_memalign
      static long nje_rallocx​(long ptr, long size, int flags)
      Unsafe version of: rallocx
      static long nje_realloc​(long ptr, long size)
      Unsafe version of: realloc
      static long nje_sallocx​(long ptr, int flags)
      Unsafe version of: sallocx
      static void nje_sdallocx​(long ptr, long size, int flags)
      Unsafe version of: sdallocx
      static long nje_xallocx​(long ptr, long size, long extra, int flags)
      Unsafe version of: xallocx
      • Methods inherited from class java.lang.Object

        equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • MALLOCX_ZERO

        Initialize newly allocated memory to contain zero bytes. In the growing reallocation case, the real size prior to reallocation defines the boundary between untouched bytes and those that are initialized to contain zero bytes. If this macro is absent, newly allocated memory is uninitialized.
      • MALLOCX_TCACHE_NONE

        Do not use a thread-specific cache (tcache). Unless MALLOCX_TCACHE(int) or MALLOCX_TCACHE_NONE is specified, an automatically managed tcache will be used under many circumstances. This macro cannot be used in the same flags argument as MALLOCX_TCACHE(tc).
      • MALLCTL_ARENAS_ALL

        Use as arena index in "arena.<i>.{purge,decay,dss}" and "stats.arenas.<i>.*" mallctl interfaces to select all arenas.
    • Method Detail

      • je_malloc_message

        public static PointerBuffer je_malloc_message()
        Returns the je_malloc_message variable.
      • nje_malloc

        public static long nje_malloc​(long size)
        Unsafe version of: malloc
      • je_malloc

        @Nullable
        public static java.nio.ByteBuffer je_malloc​(long size)
        Allocates size bytes of uninitialized memory. The allocated space is suitably aligned (after possible pointer coercion) for storage of any type of object.
        Parameters:
        size - the number of bytes to allocate
      • nje_calloc

        public static long nje_calloc​(long num,
                                      long size)
        Unsafe version of: calloc
      • je_calloc

        @Nullable
        public static java.nio.ByteBuffer je_calloc​(long num,
                                                    long size)
        Allocates space for num objects, each size bytes in length. The result is identical to calling malloc with an argument of num * size, with the exception that the allocated memory is explicitly initialized to zero bytes.
        Parameters:
        num - the number of objects to allocate
        size - the size of each object, in bytes
      • nje_posix_memalign

        public static int nje_posix_memalign​(long memptr,
                                             long alignment,
                                             long size)
        Unsafe version of: posix_memalign
      • je_posix_memalign

        public static int je_posix_memalign​(PointerBuffer memptr,
                                            long alignment,
                                            long size)
        Allocates size bytes of memory such that the allocation's base address is an even multiple of alignment, and returns the allocation in the value pointed to by memptr. The requested alignment must be a power of 2 at least as large as sizeof(void *).
        Parameters:
        memptr - returns the allocated memory
        alignment - the allocation alignment, in bytes
        size - the number of bytes to allocate
      • nje_aligned_alloc

        public static long nje_aligned_alloc​(long alignment,
                                             long size)
        Unsafe version of: aligned_alloc
      • je_aligned_alloc

        @Nullable
        public static java.nio.ByteBuffer je_aligned_alloc​(long alignment,
                                                           long size)
        Allocates size bytes of memory such that the allocation's base address is an even multiple of alignment. The requested alignment must be a power of 2. Behavior is undefined if size is not an integral multiple of alignment.
        Parameters:
        alignment - the allocation alignment, in bytes
        size - the number of bytes to allocate
      • nje_realloc

        public static long nje_realloc​(long ptr,
                                       long size)
        Unsafe version of: realloc
      • je_realloc

        @Nullable
        public static java.nio.ByteBuffer je_realloc​(@Nullable
                                                     java.nio.ByteBuffer ptr,
                                                     long size)
        Changes the size of the previously allocated memory referenced by ptr to size bytes. The contents of the memory are unchanged up to the lesser of the new and old sizes. If the new size is larger, the contents of the newly allocated portion of the memory are undefined. Upon success, the memory referenced by ptr is freed and a pointer to the newly allocated memory is returned. Note that realloc() may move the memory allocation, resulting in a different return value than ptr. If ptr is NULL, the realloc() function behaves identically to malloc() for the specified size.
        Parameters:
        ptr - the previously allocated memory or NULL
        size - the number of bytes to allocate
      • nje_free

        public static void nje_free​(long ptr)
        Unsafe version of: free
      • je_free

        public static void je_free​(@Nullable
                                   java.nio.ByteBuffer ptr)
        
        public static void je_free​(@Nullable
                                   java.nio.ShortBuffer ptr)
        
        public static void je_free​(@Nullable
                                   java.nio.IntBuffer ptr)
        
        public static void je_free​(@Nullable
                                   java.nio.LongBuffer ptr)
        
        public static void je_free​(@Nullable
                                   java.nio.FloatBuffer ptr)
        
        public static void je_free​(@Nullable
                                   java.nio.DoubleBuffer ptr)
        
        public static void je_free​(@Nullable
                                   PointerBuffer ptr)
        
        Causes the allocated memory referenced by ptr to be made available for future allocations. If ptr is NULL, no action occurs.
        Parameters:
        ptr - the allocated memory to free
      • nje_mallocx

        public static long nje_mallocx​(long size,
                                       int flags)
        Unsafe version of: mallocx
      • je_mallocx

        @Nullable
        public static java.nio.ByteBuffer je_mallocx​(long size,
                                                     int flags)
        Allocates at least size bytes of memory, and returns a pointer to the base address of the allocation. Behavior is undefined if size is 0, or if request size overflows due to size class and/or alignment constraints.
        Parameters:
        size - the number of bytes to allocate
        flags - a bitfield of zero or more of the MALLOCX macros
      • nje_rallocx

        public static long nje_rallocx​(long ptr,
                                       long size,
                                       int flags)
        Unsafe version of: rallocx
      • je_rallocx

        @Nullable
        public static java.nio.ByteBuffer je_rallocx​(@Nullable
                                                     java.nio.ByteBuffer ptr,
                                                     long size,
                                                     int flags)
        Resizes the allocation at ptr to be at least size bytes, and returns a pointer to the base address of the resulting allocation, which may or may not have moved from its original location. Behavior is undefined if size is 0, or if request size overflows due to size class and/or alignment constraints.
        Parameters:
        ptr - the previously allocated memory or NULL
        size - the number of bytes to allocate
        flags - a bitfield of zero or more of the MALLOCX macros
      • nje_xallocx

        public static long nje_xallocx​(long ptr,
                                       long size,
                                       long extra,
                                       int flags)
        Unsafe version of: xallocx
      • je_xallocx

        public static long je_xallocx​(@Nullable
                                      java.nio.ByteBuffer ptr,
                                      long size,
                                      long extra,
                                      int flags)
        Resizes the allocation at ptr in place to be at least size bytes, and returns the real size of the allocation. If extra is non-zero, an attempt is made to resize the allocation to be at least (size + extra) bytes, though inability to allocate the extra byte(s) will not by itself result in failure to resize. Behavior is undefined if size is 0, or if (size + extra > SIZE_T_MAX).
        Parameters:
        ptr - the previously allocated memory or NULL
        size - the number of bytes to allocate
        extra - the number of extra bytes to allocate
        flags - a bitfield of zero or more of the MALLOCX macros
      • nje_sallocx

        public static long nje_sallocx​(long ptr,
                                       int flags)
        Unsafe version of: sallocx
      • je_sallocx

        public static long je_sallocx​(java.nio.ByteBuffer ptr,
                                      int flags)
        Returns the real size of the allocation at ptr.
        Parameters:
        ptr - the allocated memory to query
        flags - a bitfield of zero or more of the MALLOCX macros
      • nje_dallocx

        public static void nje_dallocx​(long ptr,
                                       int flags)
        Unsafe version of: dallocx
      • je_dallocx

        public static void je_dallocx​(java.nio.ByteBuffer ptr,
                                      int flags)
        
        public static void je_dallocx​(java.nio.ShortBuffer ptr,
                                      int flags)
        
        public static void je_dallocx​(java.nio.IntBuffer ptr,
                                      int flags)
        
        public static void je_dallocx​(java.nio.LongBuffer ptr,
                                      int flags)
        
        public static void je_dallocx​(java.nio.FloatBuffer ptr,
                                      int flags)
        
        public static void je_dallocx​(java.nio.DoubleBuffer ptr,
                                      int flags)
        
        public static void je_dallocx​(PointerBuffer ptr,
                                      int flags)
        
        Causes the memory referenced by ptr to be made available for future allocations.
        Parameters:
        ptr - the allocated memory to deallocate
        flags - a bitfield of zero or more of the MALLOCX macros
      • nje_sdallocx

        public static void nje_sdallocx​(long ptr,
                                        long size,
                                        int flags)
        Unsafe version of: sdallocx
        Parameters:
        size - the number of bytes in ptr
      • je_sdallocx

        public static void je_sdallocx​(java.nio.ByteBuffer ptr,
                                       int flags)
        
        public static void je_sdallocx​(java.nio.ShortBuffer ptr,
                                       int flags)
        
        public static void je_sdallocx​(java.nio.IntBuffer ptr,
                                       int flags)
        
        public static void je_sdallocx​(java.nio.LongBuffer ptr,
                                       int flags)
        
        public static void je_sdallocx​(java.nio.FloatBuffer ptr,
                                       int flags)
        
        public static void je_sdallocx​(java.nio.DoubleBuffer ptr,
                                       int flags)
        
        public static void je_sdallocx​(PointerBuffer ptr,
                                       int flags)
        
        Sized version of dallocx. The primary optimization over dallocx() is the removal of a metadata read, which often suffers an L1 cache miss.
        Parameters:
        ptr - the allocated memory to deallocate
        flags - a bitfield of zero or more of the MALLOCX macros
      • nje_nallocx

        public static long nje_nallocx​(long size,
                                       int flags)
        Unsafe version of: nallocx
      • je_nallocx

        @Nullable
        public static java.nio.ByteBuffer je_nallocx​(long size,
                                                     int flags)
        Allocates no memory, but it performs the same size computation as the mallocx function, and returns the real size of the allocation that would result from the equivalent mallocx() function call. Behavior is undefined if size is 0, or if request size overflows due to size class and/or alignment constraints.
        Parameters:
        size - the number of bytes to allocate
        flags - a bitfield of zero or more of the MALLOCX macros
      • nje_mallctl

        public static int nje_mallctl​(long name,
                                      long oldp,
                                      long oldlenp,
                                      long newp,
                                      long newlen)
        Unsafe version of: mallctl
        Parameters:
        newlen - the new value length
      • je_mallctl

        public static int je_mallctl​(java.nio.ByteBuffer name,
                                     @Nullable
                                     java.nio.ByteBuffer oldp,
                                     @Nullable
                                     PointerBuffer oldlenp,
                                     @Nullable
                                     java.nio.ByteBuffer newp)
        
        public static int je_mallctl​(java.lang.CharSequence name,
                                     @Nullable
                                     java.nio.ByteBuffer oldp,
                                     @Nullable
                                     PointerBuffer oldlenp,
                                     @Nullable
                                     java.nio.ByteBuffer newp)
        
        Provides a general interface for introspecting the memory allocator, as well as setting modifiable parameters and triggering actions. The period-separated name argument specifies a location in a tree-structured namespace; see the MALLCTL NAMESPACE section for documentation on the tree contents. To read a value, pass a pointer via oldp to adequate space to contain the value, and a pointer to its length via oldlenp; otherwise pass NULL and NULL. Similarly, to write a value, pass a pointer to the value via newp, and its length via newlen; otherwise pass NULL and 0.
        Parameters:
        name - the namespace location
        oldp - returns a value
        oldlenp - returns the value length
        newp - the new value
      • nje_mallctlnametomib

        public static int nje_mallctlnametomib​(long name,
                                               long mibp,
                                               long miblenp)
        Unsafe version of: mallctlnametomib
        Parameters:
        miblenp - the number of components in mibp
      • je_mallctlnametomib

        public static int je_mallctlnametomib​(java.nio.ByteBuffer name,
                                              PointerBuffer mibp,
                                              PointerBuffer miblenp)
        
        public static int je_mallctlnametomib​(java.lang.CharSequence name,
                                              PointerBuffer mibp,
                                              PointerBuffer miblenp)
        
        Provides a way to avoid repeated name lookups for applications that repeatedly query the same portion of the namespace, by translating a name to a “Management Information Base” (MIB) that can be passed repeatedly to mallctlbymib. Upon successful return from mallctlnametomib(), mibp contains an array of *miblenp integers, where *miblenp is the lesser of the number of components in name and the input value of *miblenp. Thus it is possible to pass a *miblenp that is smaller than the number of period-separated name components, which results in a partial MIB that can be used as the basis for constructing a complete MIB. For name components that are integers (e.g. the 2 in "arenas.bin.2.size"), the corresponding MIB component will always be that integer. Therefore, it is legitimate to construct code like the following:
        
         unsigned nbins, i;
         size_t mib[4];
         size_t len, miblen;
         
         len = sizeof(nbins);
         mallctl("arenas.nbins", &nbins, &len, NULL, 0);
         
         miblen = 4;
         mallctlnametomib("arenas.bin.0.size", mib, &miblen);
         for (i = 0; i < nbins; i++) {
             size_t bin_size;
         
             mib[2] = i;
             len = sizeof(bin_size);
             mallctlbymib(mib, miblen, &bin_size, &len, NULL, 0);
             // Do something with bin_size...
         }
        Parameters:
        name - the namespace location
        mibp - an array of integers
        miblenp - the number of components in mibp
      • nje_mallctlbymib

        public static int nje_mallctlbymib​(long mib,
                                           long miblen,
                                           long oldp,
                                           long oldlenp,
                                           long newp,
                                           long newlen)
        Unsafe version of: mallctlbymib
        Parameters:
        miblen - the number of elements in mib
        newlen - the new value length
      • je_mallctlbymib

        public static int je_mallctlbymib​(PointerBuffer mib,
                                          @Nullable
                                          java.nio.ByteBuffer oldp,
                                          @Nullable
                                          PointerBuffer oldlenp,
                                          @Nullable
                                          java.nio.ByteBuffer newp)
        Similar to mallctl, but uses MIBs instead of names. See mallctlnametomib for details.
        Parameters:
        mib - a MIB
        oldp - returns a value
        oldlenp - returns the value length
        newp - the new value
      • nje_malloc_stats_print

        public static void nje_malloc_stats_print​(long write_cb,
                                                  long cbopaque,
                                                  long opts)
        Unsafe version of: malloc_stats_print
      • je_malloc_stats_print

        public static void je_malloc_stats_print​(@Nullable
                                                 MallocMessageCallbackI write_cb,
                                                 long cbopaque,
                                                 @Nullable
                                                 java.nio.ByteBuffer opts)
        
        public static void je_malloc_stats_print​(@Nullable
                                                 MallocMessageCallbackI write_cb,
                                                 long cbopaque,
                                                 @Nullable
                                                 java.lang.CharSequence opts)
        
        Writes human-readable summary statistics via the write_cb callback function pointer and cbopaque data passed to write_cb, or malloc_message() if write_cb is NULL. This function can be called repeatedly. General information that never changes during execution can be omitted by specifying "g" as a character within the opts string. Note that malloc_message() uses the mallctl*() functions internally, so inconsistent statistics can be reported if multiple threads use these functions simultaneously. If --enable-stats is specified during configuration, “m” and “a” can be specified to omit merged arena and per arena statistics, respectively; “b” and “l” can be specified to omit per size class statistics for bins and large objects, respectively. Unrecognized characters are silently ignored. Note that thread caching may prevent some statistics from being completely up to date, since extra locking would be required to merge counters that track thread cache operations.
        Parameters:
        write_cb - the print callback, or NULL to use malloc_message()
        cbopaque - an opaque pointer that will be passed to write_cb
        opts - an options string
      • nje_malloc_usable_size

        public static long nje_malloc_usable_size​(long ptr)
        Unsafe version of: malloc_usable_size
      • je_malloc_usable_size

        public static long je_malloc_usable_size​(java.nio.ByteBuffer ptr)
        Returns the usable size of the allocation pointed to by ptr. The return value may be larger than the size that was requested during allocation. The malloc_usable_size() function is not a mechanism for in-place realloc; rather it is provided solely as a tool for introspection purposes. Any discrepancy between the requested allocation size and the size reported by malloc_usable_size() should not be depended on, since such behavior is entirely implementation-dependent.
        Parameters:
        ptr - the allocated memory to query
      • MALLOCX_LG_ALIGN

        public static int MALLOCX_LG_ALIGN​(int la)
        Align the memory allocation to start at an address that is a multiple of (1 << la). This macro does not validate that la is within the valid range.
        Parameters:
        la - the alignment shift
      • MALLOCX_ALIGN

        public static int MALLOCX_ALIGN​(int a)
        Align the memory allocation to start at an address that is a multiple of a, where a is a power of two. This macro does not validate that a is a power of 2.
        Parameters:
        a - the alignment
      • MALLOCX_TCACHE

        public static int MALLOCX_TCACHE​(int tc)
        Use the thread-specific cache (tcache) specified by the identifier tc, which must have been acquired via the tcache.create mallctl. This macro does not validate that tc specifies a valid identifier.
        Parameters:
        tc - the thread-specific cache
      • MALLOCX_ARENA

        public static int MALLOCX_ARENA​(int a)
        Use the arena specified by the index a (and by necessity bypass the thread cache). This macro has no effect for huge regions, nor for regions that were allocated via an arena other than the one specified. This macro does not validate that a specifies an arena index in the valid range.
        Parameters:
        a - the arena index