Re: realloc function

[Cliff Wickman <cpw@sgi.com>]

Hi Vasileios,

Thanks for the patch.
I'm putting in my to-do list for 2.0.7.
I'll let you know when it's in a release candidate tarball.

-Cliff

On Mon, Jan 03, 2011 at 11:56:42PM +0200, Vasileios Karakasis wrote:
> Hi,
> 
> I am sending you the updated patch (against the latest 2.0.6 version). I
> call numa_police_memory_int() only for the newly allocated pages, when
> the area is expanded. I also added a numa_realloc_onnode() function in
> the same fashion as that of the numa_alloc_onnode(), which sets a
> specific memory binding. I pass the MPOL_MF_MOVE flag to mbind(), but I
> am not sure if this is worth it, since  the call becomes too slow even
> in the case of no page migration. Without the MPOL_MF_MOVE flag, of
> course, if the policy changes between realloc's, previously allocated
> pages won't be affected.
> 
> Regards,
> 
> On 01/03/2011 01:42 AM, Andi Kleen wrote:
> > 
> >> I am submitting a patch for a realloc function that might be useful. The
> >> proposed numa_realloc() is merely a wrapper to mremap(), which it calls
> >> with the flag MREMAP_MAYMOVE. The policy of the vm area is copied by the
> >> kernel in case of moving. I am also submitting a test program, that
> >> keeps expanding an initial allocation until a limit is reached and
> >> checks the mempolicy of the expanded area in every iteration.
> >>
> >> My use case is a dynamic array implementation which uses realloc() to
> >> dynamically expand the array and I want to convert it to a numa-aware
> >> implementation.
> > 
> > You need to call numa_police_memory_int() in the function, otherwise
> > the policy won't be actually preserved.
> > 
> > -Andi
> > 
> > 
> 
> -- 
> V.K.

> diff -urN numactl-2.0.6-orig/libnuma.c numactl-2.0.6/libnuma.c
> --- numactl-2.0.6-orig/libnuma.c	2011-01-03 15:09:23.000000000 +0200
> +++ numactl-2.0.6/libnuma.c	2011-01-03 23:15:14.000000000 +0200
> @@ -871,6 +871,17 @@
>  	return mem;
>  } 
>  
> +void *numa_realloc(void *old_addr, size_t old_size, size_t new_size)
> +{
> +	char *mem;
> +	mem = mremap(old_addr, old_size, new_size, MREMAP_MAYMOVE);
> +	if (mem == (char *)-1)
> +		return NULL;
> +	if (new_size > old_size)
> +		numa_police_memory_int(mem + old_size, new_size - old_size);
> +	return mem;
> +}
> +
>  void *numa_alloc_interleaved_subset_v1(size_t size, const nodemask_t *mask)
>  {
>  	char *mem;
> @@ -997,6 +1008,28 @@
>  	return mem; 	
>  } 
>  
> +void *numa_realloc_onnode(void *old_addr, size_t old_size, size_t new_size,
> +						  int node)
> +{
> +	char *mem;
> +	struct bitmask *bmp;
> +
> +	bmp = numa_allocate_nodemask();
> +	numa_bitmask_setbit(bmp, node);
> +	mem = mremap(old_addr, old_size, new_size, MREMAP_MAYMOVE);
> +	if (mem == (char *)-1) {
> +		mem = NULL;
> +	} else {
> +		unsigned int mbind_flags_save = mbind_flags;
> +		mbind_flags |= MPOL_MF_MOVE;
> +		dombind(mem, new_size, bind_policy, bmp);
> +		mbind_flags = mbind_flags_save;
> +	}
> +
> +	numa_bitmask_free(bmp);
> +	return mem;
> +}
> +
>  void *numa_alloc_local(size_t size) 
>  { 
>  	char *mem; 
> diff -urN numactl-2.0.6-orig/Makefile numactl-2.0.6/Makefile
> --- numactl-2.0.6-orig/Makefile	2011-01-03 15:09:23.000000000 +0200
> +++ numactl-2.0.6/Makefile	2011-01-03 23:22:57.000000000 +0200
> @@ -31,7 +31,7 @@
>  	      test/after test/before threadtest test_move_pages \
>  	      test/mbind_mig_pages test/migrate_pages \
>  	      migratepages migspeed migspeed.o libnuma.a \
> -	      test/move_pages
> +	      test/move_pages test/realloc_test
>  SOURCES := bitops.c libnuma.c distance.c memhog.c numactl.c numademo.c \
>  	numamon.c shm.c stream_lib.c stream_main.c syscall.c util.c mt.c \
>  	clearcache.c test/*.c
> @@ -43,7 +43,7 @@
>  all: numactl migratepages migspeed libnuma.so numademo numamon memhog \
>       test/tshared stream test/mynode test/pagesize test/ftok test/prefered \
>       test/randmap test/nodemap test/distance test/tbitmap test/move_pages \
> -     test/mbind_mig_pages test/migrate_pages libnuma.a
> +     test/mbind_mig_pages test/migrate_pages test/realloc_test libnuma.a
>  
>  numactl: numactl.o util.o shm.o bitops.o libnuma.so
>  
> @@ -123,6 +123,8 @@
>  
>  test/migrate_pages: test/migrate_pages.c libnuma.so
>  
> +test/realloc_test: test/realloc_test.c libnuma.so
> +
>  .PHONY: install all clean html depend
>  
>  MANPAGES := numa.3 numactl.8 numastat.8 migratepages.8 migspeed.8
> diff -urN numactl-2.0.6-orig/numa.h numactl-2.0.6/numa.h
> --- numactl-2.0.6-orig/numa.h	2011-01-03 15:09:23.000000000 +0200
> +++ numactl-2.0.6/numa.h	2011-01-03 21:06:08.000000000 +0200
> @@ -208,10 +208,14 @@
>  void *numa_alloc_interleaved(size_t size);
>  /* Alloc memory located on node */
>  void *numa_alloc_onnode(size_t size, int node);
> +/* Realloc memory located on node */
> +void *numa_realloc_onnode(void *old_addr, size_t old_size, size_t new_size, int node);
>  /* Alloc memory on local node */
>  void *numa_alloc_local(size_t size);
>  /* Allocation with current policy */
>  void *numa_alloc(size_t size);
> +/* Realloc memory, binding properties are preserved. */
> +void *numa_realloc(void *old_addr, size_t old_size, size_t new_size);
>  /* Free memory allocated by the functions above */
>  void numa_free(void *mem, size_t size);
>  
> Binary files numactl-2.0.6-orig/test/move_pages and numactl-2.0.6/test/move_pages differ
> diff -urN numactl-2.0.6-orig/test/realloc_test.c numactl-2.0.6/test/realloc_test.c
> --- numactl-2.0.6-orig/test/realloc_test.c	1970-01-01 02:00:00.000000000 +0200
> +++ numactl-2.0.6/test/realloc_test.c	2011-01-03 23:19:31.000000000 +0200
> @@ -0,0 +1,119 @@
> +#include <assert.h>
> +#include <errno.h>
> +#include <limits.h>
> +#include <unistd.h>
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <sys/mman.h>
> +#include "numa.h"
> +#include "numaif.h"
> +
> +#define DEFAULT_NR_PAGES	1024
> +
> +static int parse_int(const char *str)
> +{
> +	char	*endptr;
> +	long	ret = strtol(str, &endptr, 0);
> +	if (*endptr != '\0') {
> +		fprintf(stderr, "[error] strtol() failed: parse error: %s\n", endptr);
> +		exit(1);
> +	}
> +
> +	if (errno == ERANGE)
> +		fprintf(stderr, "[warning] strtol() out of range\n");
> +
> +	if (ret > INT_MAX || ret < INT_MIN) {
> +		fprintf(stderr, "[warning] parse_int() out of range\n");
> +		ret = (ret > 0) ? INT_MAX : INT_MIN;
> +	}
> +
> +	return (int) ret;
> +}
> +
> +int main(int argc, char **argv)
> +{
> +	char	*mem;
> +	int		page_size = numa_pagesize();
> +	int		node = 0;
> +	int		nr_pages = DEFAULT_NR_PAGES;
> +
> +	if (numa_available() < 0) {
> +		fprintf(stderr, "numa is not available");
> +		exit(1);
> +	}
> +
> +	if (argc > 1)
> +		node = parse_int(argv[1]);
> +	if (argc > 2)
> +		nr_pages = parse_int(argv[2]);
> +	
> +	mem = numa_alloc_onnode(page_size, node);
> +
> +	/* Store the policy of the newly allocated area */
> +	unsigned long	nodemask;
> +	int				mode;
> +	int				nr_nodes = numa_num_possible_nodes();
> +	if (get_mempolicy(&mode, &nodemask, nr_nodes, mem,
> +					  MPOL_F_NODE | MPOL_F_ADDR) < 0) {
> +		perror("get_mempolicy() failed");
> +		exit(1);
> +	}
> +
> +	/* Print some info */
> +	printf("Page size: %d\n", page_size);
> +	printf("Pages realloc'ed: %d\n", nr_pages);
> +	printf("Allocate data in node: %d\n", node);
> +
> +	/* Request pages until a realloc moves the data */
> +	int i;
> +	int nr_inplace = 0;
> +	int nr_moved   = 0;
> +	for (i = 0; i < nr_pages; i++) {
> +		/* Enlarge mem with one more page */
> +#ifdef TEST_REALLOC_ONNODE
> +		char	*new_mem = numa_realloc_onnode(mem,
> +											   (i+1)*page_size,
> +											   (i+2)*page_size, node);
> +#else
> +		char	*new_mem = numa_realloc(mem, (i+1)*page_size, (i+2)*page_size);
> +#endif
> +		if (!new_mem) {
> +			perror("numa_realloc() failed");
> +			exit(1);
> +		}
> +
> +		if (new_mem == mem)
> +			++nr_inplace;
> +		else
> +			++nr_moved;
> +		mem = new_mem;
> +
> +		/* Check the policy of the realloc'ed area */
> +		unsigned long	realloc_nodemask;
> +		int				realloc_mode;
> +		if (get_mempolicy(&realloc_mode, &realloc_nodemask,
> +						  nr_nodes, mem, MPOL_F_NODE | MPOL_F_ADDR) < 0) {
> +			perror("get_mempolicy() failed");
> +			exit(1);
> +		}
> +
> +		assert(realloc_nodemask == nodemask &&
> +			   realloc_mode == mode && "policy changed");
> +	}
> +
> +	/* Shrink to the original size */
> +#ifdef TEST_REALLOC_ONNODE
> +	mem = numa_realloc_onnode(mem, (nr_pages + 1)*page_size, page_size, node);
> +#else
> +	mem = numa_realloc(mem, (nr_pages + 1)*page_size, page_size);
> +#endif	
> +	if (!mem) {
> +		perror("numa_realloc() failed");
> +		exit(1);
> +	}
> +
> +	numa_free(mem, page_size);
> +	printf("In-place reallocs: %d\n", nr_inplace);
> +	printf("Moved reallocs: %d\n", nr_moved);
> +	return 0;
> +}
> diff -urN numactl-2.0.6-orig/versions.ldscript numactl-2.0.6/versions.ldscript
> --- numactl-2.0.6-orig/versions.ldscript	2011-01-03 15:09:23.000000000 +0200
> +++ numactl-2.0.6/versions.ldscript	2011-01-03 21:09:13.000000000 +0200
> @@ -87,6 +87,8 @@
>      numa_alloc_interleaved_subset;
>      numa_alloc_local;
>      numa_alloc_onnode;
> +    numa_realloc_onnode;
> +    numa_realloc;
>      numa_allocate_cpumask;
>      numa_allocate_nodemask;
>      numa_available;




-- 
Cliff Wickman
SGI
cpw@sgi.com
(651) 683-3824