mm: move_pages syscall can't return ENOENT when pages are not present

mm: move_pages syscall can't return ENOENT when pages are not present

[Zhouping Liu]

hi, all

Recently, I found an error in move_pages syscall:

depending on move_pages(2), when page is not present,
it should fail with ENOENT, in fact, it's ok without
any errno.

the following reproducer can easily reproduce
the issue, suggest you get more details by strace.
inside reproducer, I try to move a non-exist page from
node 1 to node 0.

I have tested it on the latest kernel 3.4-rc5 with 2 and 4 numa nodes.
[zliu@ZhoupingLiu ~]$ gcc -o reproducer reproducer.c -lnuma
[zliu@ZhoupingLiu ~]$ ./reproducer 
from_node is 1, to_node is 0
ERROR: move_pages expected FAIL.

I'm not in mail list, please CC me.

/*
 * Copyright (C) 2012  Red Hat, Inc.
 *
 * This work is licensed under the terms of the GNU GPL, version 2. See
 * the COPYING file in the top-level directory.
 *
 * Compiled: gcc -o reproducer reproducer.c -lnuma
 * Description:
 * it's designed to check move_pages syscall, when
 * page is not present, it should fail with ENOENT.
 */

#include <sys/mman.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <numa.h>
#include <numaif.h>

#define TEST_PAGES 4

int main(int argc, char **argv)
{
	void *pages[TEST_PAGES];
	int onepage;
	int nodes[TEST_PAGES];
	int status, ret;
	int i, from_node = 1, to_node = 0;

	onepage = getpagesize();

	for (i = 0; i < TEST_PAGES - 1; i++) {
		pages[i] = numa_alloc_onnode(onepage, from_node);
		nodes[i] = to_node;
	}

	nodes[TEST_PAGES - 1] = to_node;

	/*
	 * the follow page is not available, also not aligned,
	 * depend on move_pages(2), it can't be moved, and should
	 * return ENOENT errno.
	 */
	pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4 + 1;

	printf("from_node is %u, to_node is %u\n", from_node, to_node);
	ret = move_pages(0, TEST_PAGES, pages, nodes, &status, MPOL_MF_MOVE);
	if (ret == -1) {
		if (errno != ENOENT)
			perror("move_pages expected ENOENT errno, but it's");
		else
			printf("Succeed\n");
	} else {
		printf("ERROR: move_pages expected FAIL.\n");
	}

	for (i = 0; i < TEST_PAGES; i++)
		numa_free(pages[i], onepage);

	return 0;
}

-- 
Thanks,
Zhouping

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mm: move_pages syscall can't return ENOENT when pages are not present

[Zhouping Liu]

hi, all

Recently, I found an error in move_pages syscall:

depending on move_pages(2), when page is not present,
it should fail with ENOENT, in fact, it's ok without
any errno.

the following reproducer can easily reproduce
the issue, suggest you get more details by strace.
inside reproducer, I try to move a non-exist page from
node 1 to node 0.

I have tested it on the latest kernel 3.4-rc5 with 2 and 4 numa nodes.
[zliu@ZhoupingLiu ~]$ gcc -o reproducer reproducer.c -lnuma
[zliu@ZhoupingLiu ~]$ ./reproducer 
from_node is 1, to_node is 0
ERROR: move_pages expected FAIL.

I'm not in mail list, please CC me.

/*
 * Copyright (C) 2012  Red Hat, Inc.
 *
 * This work is licensed under the terms of the GNU GPL, version 2. See
 * the COPYING file in the top-level directory.
 *
 * Compiled: gcc -o reproducer reproducer.c -lnuma
 * Description:
 * it's designed to check move_pages syscall, when
 * page is not present, it should fail with ENOENT.
 */

#include <sys/mman.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <numa.h>
#include <numaif.h>

#define TEST_PAGES 4

int main(int argc, char **argv)
{
	void *pages[TEST_PAGES];
	int onepage;
	int nodes[TEST_PAGES];
	int status, ret;
	int i, from_node = 1, to_node = 0;

	onepage = getpagesize();

	for (i = 0; i < TEST_PAGES - 1; i++) {
		pages[i] = numa_alloc_onnode(onepage, from_node);
		nodes[i] = to_node;
	}

	nodes[TEST_PAGES - 1] = to_node;

	/*
	 * the follow page is not available, also not aligned,
	 * depend on move_pages(2), it can't be moved, and should
	 * return ENOENT errno.
	 */
	pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4 + 1;

	printf("from_node is %u, to_node is %u\n", from_node, to_node);
	ret = move_pages(0, TEST_PAGES, pages, nodes, &status, MPOL_MF_MOVE);
	if (ret == -1) {
		if (errno != ENOENT)
			perror("move_pages expected ENOENT errno, but it's");
		else
			printf("Succeed\n");
	} else {
		printf("ERROR: move_pages expected FAIL.\n");
	}

	for (i = 0; i < TEST_PAGES; i++)
		numa_free(pages[i], onepage);

	return 0;
}

-- 
Thanks,
Zhouping

Re: mm: move_pages syscall can't return ENOENT when pages are not present

[Xiaotian Feng]

On Wed, May 9, 2012 at 4:58 PM, Zhouping Liu <zliu@redhat.com> wrote:
> hi, all
>
> Recently, I found an error in move_pages syscall:
>
> depending on move_pages(2), when page is not present,
> it should fail with ENOENT, in fact, it's ok without
> any errno.
>
> the following reproducer can easily reproduce
> the issue, suggest you get more details by strace.
> inside reproducer, I try to move a non-exist page from
> node 1 to node 0.
>
> I have tested it on the latest kernel 3.4-rc5 with 2 and 4 numa nodes.
> [zliu@ZhoupingLiu ~]$ gcc -o reproducer reproducer.c -lnuma
> [zliu@ZhoupingLiu ~]$ ./reproducer
> from_node is 1, to_node is 0
> ERROR: move_pages expected FAIL.
>

" If nodes is not NULL, move_pages returns the number of valid
migration requests which could not currently be performed.  Otherwise
it returns 0."

> I'm not in mail list, please CC me.
>
> /*
>  * Copyright (C) 2012  Red Hat, Inc.
>  *
>  * This work is licensed under the terms of the GNU GPL, version 2. See
>  * the COPYING file in the top-level directory.
>  *
>  * Compiled: gcc -o reproducer reproducer.c -lnuma
>  * Description:
>  * it's designed to check move_pages syscall, when
>  * page is not present, it should fail with ENOENT.
>  */
>
> #include <sys/mman.h>
> #include <sys/types.h>
> #include <sys/wait.h>
> #include <stdio.h>
> #include <unistd.h>
> #include <errno.h>
> #include <numa.h>
> #include <numaif.h>
>
> #define TEST_PAGES 4
>
> int main(int argc, char **argv)
> {
>        void *pages[TEST_PAGES];
>        int onepage;
>        int nodes[TEST_PAGES];
>        int status, ret;
>        int i, from_node = 1, to_node = 0;
>
>        onepage = getpagesize();
>
>        for (i = 0; i < TEST_PAGES - 1; i++) {
>                pages[i] = numa_alloc_onnode(onepage, from_node);
>                nodes[i] = to_node;
>        }
>
>        nodes[TEST_PAGES - 1] = to_node;
>
>        /*
>         * the follow page is not available, also not aligned,
>         * depend on move_pages(2), it can't be moved, and should
>         * return ENOENT errno.
>         */
>        pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4 + 1;
>
>        printf("from_node is %u, to_node is %u\n", from_node, to_node);
>        ret = move_pages(0, TEST_PAGES, pages, nodes, &status, MPOL_MF_MOVE);
>        if (ret == -1) {
>                if (errno != ENOENT)
>                        perror("move_pages expected ENOENT errno, but it's");
>                else
>                        printf("Succeed\n");
>        } else {
>                printf("ERROR: move_pages expected FAIL.\n");
>        }
>
>        for (i = 0; i < TEST_PAGES; i++)
>                numa_free(pages[i], onepage);
>
>        return 0;
> }
>
> --
> Thanks,
> Zhouping
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

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Re: mm: move_pages syscall can't return ENOENT when pages are not present

[Xiaotian Feng]

On Wed, May 9, 2012 at 4:58 PM, Zhouping Liu <zliu@redhat.com> wrote:
> hi, all
>
> Recently, I found an error in move_pages syscall:
>
> depending on move_pages(2), when page is not present,
> it should fail with ENOENT, in fact, it's ok without
> any errno.
>
> the following reproducer can easily reproduce
> the issue, suggest you get more details by strace.
> inside reproducer, I try to move a non-exist page from
> node 1 to node 0.
>
> I have tested it on the latest kernel 3.4-rc5 with 2 and 4 numa nodes.
> [zliu@ZhoupingLiu ~]$ gcc -o reproducer reproducer.c -lnuma
> [zliu@ZhoupingLiu ~]$ ./reproducer
> from_node is 1, to_node is 0
> ERROR: move_pages expected FAIL.
>

" If nodes is not NULL, move_pages returns the number of valid
migration requests which could not currently be performed.  Otherwise
it returns 0."

> I'm not in mail list, please CC me.
>
> /*
>  * Copyright (C) 2012  Red Hat, Inc.
>  *
>  * This work is licensed under the terms of the GNU GPL, version 2. See
>  * the COPYING file in the top-level directory.
>  *
>  * Compiled: gcc -o reproducer reproducer.c -lnuma
>  * Description:
>  * it's designed to check move_pages syscall, when
>  * page is not present, it should fail with ENOENT.
>  */
>
> #include <sys/mman.h>
> #include <sys/types.h>
> #include <sys/wait.h>
> #include <stdio.h>
> #include <unistd.h>
> #include <errno.h>
> #include <numa.h>
> #include <numaif.h>
>
> #define TEST_PAGES 4
>
> int main(int argc, char **argv)
> {
>        void *pages[TEST_PAGES];
>        int onepage;
>        int nodes[TEST_PAGES];
>        int status, ret;
>        int i, from_node = 1, to_node = 0;
>
>        onepage = getpagesize();
>
>        for (i = 0; i < TEST_PAGES - 1; i++) {
>                pages[i] = numa_alloc_onnode(onepage, from_node);
>                nodes[i] = to_node;
>        }
>
>        nodes[TEST_PAGES - 1] = to_node;
>
>        /*
>         * the follow page is not available, also not aligned,
>         * depend on move_pages(2), it can't be moved, and should
>         * return ENOENT errno.
>         */
>        pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4 + 1;
>
>        printf("from_node is %u, to_node is %u\n", from_node, to_node);
>        ret = move_pages(0, TEST_PAGES, pages, nodes, &status, MPOL_MF_MOVE);
>        if (ret == -1) {
>                if (errno != ENOENT)
>                        perror("move_pages expected ENOENT errno, but it's");
>                else
>                        printf("Succeed\n");
>        } else {
>                printf("ERROR: move_pages expected FAIL.\n");
>        }
>
>        for (i = 0; i < TEST_PAGES; i++)
>                numa_free(pages[i], onepage);
>
>        return 0;
> }
>
> --
> Thanks,
> Zhouping
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

Re: [LTP] mm: move_pages syscall can't return ENOENT when pages are not present

[Wanlong Gao]

On 05/09/2012 05:28 PM, Xiaotian Feng wrote:

> On Wed, May 9, 2012 at 4:58 PM, Zhouping Liu <zliu@redhat.com> wrote:
>> hi, all
>>
>> Recently, I found an error in move_pages syscall:
>>
>> depending on move_pages(2), when page is not present,
>> it should fail with ENOENT, in fact, it's ok without
>> any errno.
>>
>> the following reproducer can easily reproduce
>> the issue, suggest you get more details by strace.
>> inside reproducer, I try to move a non-exist page from
>> node 1 to node 0.
>>
>> I have tested it on the latest kernel 3.4-rc5 with 2 and 4 numa nodes.
>> [zliu@ZhoupingLiu ~]$ gcc -o reproducer reproducer.c -lnuma
>> [zliu@ZhoupingLiu ~]$ ./reproducer
>> from_node is 1, to_node is 0
>> ERROR: move_pages expected FAIL.
>>
> 
> " If nodes is not NULL, move_pages returns the number of valid
> migration requests which could not currently be performed.  Otherwise
> it returns 0."


FYI, actually, 
commit e78bbfa8262424417a29349a8064a535053912b9
Author: Brice Goglin <Brice.Goglin@inria.fr>
Date:   Sat Oct 18 20:27:15 2008 -0700

    mm: stop returning -ENOENT from sys_move_pages() if nothing got migrated

this commit changed the behaviour.

And the LTP has fixed to be consistent with this,
https://github.com/linux-test-project/ltp/commit/338299da1ff27c7815183c1b07eb91e705f117ce


Thanks,
Wanlong Gao

> 
>> I'm not in mail list, please CC me.
>>
>> /*
>>  * Copyright (C) 2012  Red Hat, Inc.
>>  *
>>  * This work is licensed under the terms of the GNU GPL, version 2. See
>>  * the COPYING file in the top-level directory.
>>  *
>>  * Compiled: gcc -o reproducer reproducer.c -lnuma
>>  * Description:
>>  * it's designed to check move_pages syscall, when
>>  * page is not present, it should fail with ENOENT.
>>  */
>>
>> #include <sys/mman.h>
>> #include <sys/types.h>
>> #include <sys/wait.h>
>> #include <stdio.h>
>> #include <unistd.h>
>> #include <errno.h>
>> #include <numa.h>
>> #include <numaif.h>
>>
>> #define TEST_PAGES 4
>>
>> int main(int argc, char **argv)
>> {
>>        void *pages[TEST_PAGES];
>>        int onepage;
>>        int nodes[TEST_PAGES];
>>        int status, ret;
>>        int i, from_node = 1, to_node = 0;
>>
>>        onepage = getpagesize();
>>
>>        for (i = 0; i < TEST_PAGES - 1; i++) {
>>                pages[i] = numa_alloc_onnode(onepage, from_node);
>>                nodes[i] = to_node;
>>        }
>>
>>        nodes[TEST_PAGES - 1] = to_node;
>>
>>        /*
>>         * the follow page is not available, also not aligned,
>>         * depend on move_pages(2), it can't be moved, and should
>>         * return ENOENT errno.
>>         */
>>        pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4 + 1;
>>
>>        printf("from_node is %u, to_node is %u\n", from_node, to_node);
>>        ret = move_pages(0, TEST_PAGES, pages, nodes, &status, MPOL_MF_MOVE);
>>        if (ret == -1) {
>>                if (errno != ENOENT)
>>                        perror("move_pages expected ENOENT errno, but it's");
>>                else
>>                        printf("Succeed\n");
>>        } else {
>>                printf("ERROR: move_pages expected FAIL.\n");
>>        }
>>
>>        for (i = 0; i < TEST_PAGES; i++)
>>                numa_free(pages[i], onepage);
>>
>>        return 0;
>> }
>>
>> --
>> Thanks,
>> Zhouping
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at  http://www.tux.org/lkml/
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
> 



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Re: mm: move_pages syscall can't return ENOENT when pages are not present

[Wanlong Gao]

On 05/09/2012 05:28 PM, Xiaotian Feng wrote:

> On Wed, May 9, 2012 at 4:58 PM, Zhouping Liu <zliu@redhat.com> wrote:
>> hi, all
>>
>> Recently, I found an error in move_pages syscall:
>>
>> depending on move_pages(2), when page is not present,
>> it should fail with ENOENT, in fact, it's ok without
>> any errno.
>>
>> the following reproducer can easily reproduce
>> the issue, suggest you get more details by strace.
>> inside reproducer, I try to move a non-exist page from
>> node 1 to node 0.
>>
>> I have tested it on the latest kernel 3.4-rc5 with 2 and 4 numa nodes.
>> [zliu@ZhoupingLiu ~]$ gcc -o reproducer reproducer.c -lnuma
>> [zliu@ZhoupingLiu ~]$ ./reproducer
>> from_node is 1, to_node is 0
>> ERROR: move_pages expected FAIL.
>>
> 
> " If nodes is not NULL, move_pages returns the number of valid
> migration requests which could not currently be performed.  Otherwise
> it returns 0."


FYI, actually, 
commit e78bbfa8262424417a29349a8064a535053912b9
Author: Brice Goglin <Brice.Goglin@inria.fr>
Date:   Sat Oct 18 20:27:15 2008 -0700

    mm: stop returning -ENOENT from sys_move_pages() if nothing got migrated

this commit changed the behaviour.

And the LTP has fixed to be consistent with this,
https://github.com/linux-test-project/ltp/commit/338299da1ff27c7815183c1b07eb91e705f117ce


Thanks,
Wanlong Gao

> 
>> I'm not in mail list, please CC me.
>>
>> /*
>>  * Copyright (C) 2012  Red Hat, Inc.
>>  *
>>  * This work is licensed under the terms of the GNU GPL, version 2. See
>>  * the COPYING file in the top-level directory.
>>  *
>>  * Compiled: gcc -o reproducer reproducer.c -lnuma
>>  * Description:
>>  * it's designed to check move_pages syscall, when
>>  * page is not present, it should fail with ENOENT.
>>  */
>>
>> #include <sys/mman.h>
>> #include <sys/types.h>
>> #include <sys/wait.h>
>> #include <stdio.h>
>> #include <unistd.h>
>> #include <errno.h>
>> #include <numa.h>
>> #include <numaif.h>
>>
>> #define TEST_PAGES 4
>>
>> int main(int argc, char **argv)
>> {
>>        void *pages[TEST_PAGES];
>>        int onepage;
>>        int nodes[TEST_PAGES];
>>        int status, ret;
>>        int i, from_node = 1, to_node = 0;
>>
>>        onepage = getpagesize();
>>
>>        for (i = 0; i < TEST_PAGES - 1; i++) {
>>                pages[i] = numa_alloc_onnode(onepage, from_node);
>>                nodes[i] = to_node;
>>        }
>>
>>        nodes[TEST_PAGES - 1] = to_node;
>>
>>        /*
>>         * the follow page is not available, also not aligned,
>>         * depend on move_pages(2), it can't be moved, and should
>>         * return ENOENT errno.
>>         */
>>        pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4 + 1;
>>
>>        printf("from_node is %u, to_node is %u\n", from_node, to_node);
>>        ret = move_pages(0, TEST_PAGES, pages, nodes, &status, MPOL_MF_MOVE);
>>        if (ret == -1) {
>>                if (errno != ENOENT)
>>                        perror("move_pages expected ENOENT errno, but it's");
>>                else
>>                        printf("Succeed\n");
>>        } else {
>>                printf("ERROR: move_pages expected FAIL.\n");
>>        }
>>
>>        for (i = 0; i < TEST_PAGES; i++)
>>                numa_free(pages[i], onepage);
>>
>>        return 0;
>> }
>>
>> --
>> Thanks,
>> Zhouping
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at  http://www.tux.org/lkml/
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
> 

Re: mm: move_pages syscall can't return ENOENT when pages are not present

[Wanlong Gao]

On 05/09/2012 05:28 PM, Xiaotian Feng wrote:

> On Wed, May 9, 2012 at 4:58 PM, Zhouping Liu <zliu@redhat.com> wrote:
>> hi, all
>>
>> Recently, I found an error in move_pages syscall:
>>
>> depending on move_pages(2), when page is not present,
>> it should fail with ENOENT, in fact, it's ok without
>> any errno.
>>
>> the following reproducer can easily reproduce
>> the issue, suggest you get more details by strace.
>> inside reproducer, I try to move a non-exist page from
>> node 1 to node 0.
>>
>> I have tested it on the latest kernel 3.4-rc5 with 2 and 4 numa nodes.
>> [zliu@ZhoupingLiu ~]$ gcc -o reproducer reproducer.c -lnuma
>> [zliu@ZhoupingLiu ~]$ ./reproducer
>> from_node is 1, to_node is 0
>> ERROR: move_pages expected FAIL.
>>
> 
> " If nodes is not NULL, move_pages returns the number of valid
> migration requests which could not currently be performed.  Otherwise
> it returns 0."


FYI, actually, 
commit e78bbfa8262424417a29349a8064a535053912b9
Author: Brice Goglin <Brice.Goglin@inria.fr>
Date:   Sat Oct 18 20:27:15 2008 -0700

    mm: stop returning -ENOENT from sys_move_pages() if nothing got migrated

this commit changed the behaviour.

And the LTP has fixed to be consistent with this,
https://github.com/linux-test-project/ltp/commit/338299da1ff27c7815183c1b07eb91e705f117ce


Thanks,
Wanlong Gao

> 
>> I'm not in mail list, please CC me.
>>
>> /*
>>  * Copyright (C) 2012  Red Hat, Inc.
>>  *
>>  * This work is licensed under the terms of the GNU GPL, version 2. See
>>  * the COPYING file in the top-level directory.
>>  *
>>  * Compiled: gcc -o reproducer reproducer.c -lnuma
>>  * Description:
>>  * it's designed to check move_pages syscall, when
>>  * page is not present, it should fail with ENOENT.
>>  */
>>
>> #include <sys/mman.h>
>> #include <sys/types.h>
>> #include <sys/wait.h>
>> #include <stdio.h>
>> #include <unistd.h>
>> #include <errno.h>
>> #include <numa.h>
>> #include <numaif.h>
>>
>> #define TEST_PAGES 4
>>
>> int main(int argc, char **argv)
>> {
>>        void *pages[TEST_PAGES];
>>        int onepage;
>>        int nodes[TEST_PAGES];
>>        int status, ret;
>>        int i, from_node = 1, to_node = 0;
>>
>>        onepage = getpagesize();
>>
>>        for (i = 0; i < TEST_PAGES - 1; i++) {
>>                pages[i] = numa_alloc_onnode(onepage, from_node);
>>                nodes[i] = to_node;
>>        }
>>
>>        nodes[TEST_PAGES - 1] = to_node;
>>
>>        /*
>>         * the follow page is not available, also not aligned,
>>         * depend on move_pages(2), it can't be moved, and should
>>         * return ENOENT errno.
>>         */
>>        pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4 + 1;
>>
>>        printf("from_node is %u, to_node is %u\n", from_node, to_node);
>>        ret = move_pages(0, TEST_PAGES, pages, nodes, &status, MPOL_MF_MOVE);
>>        if (ret == -1) {
>>                if (errno != ENOENT)
>>                        perror("move_pages expected ENOENT errno, but it's");
>>                else
>>                        printf("Succeed\n");
>>        } else {
>>                printf("ERROR: move_pages expected FAIL.\n");
>>        }
>>
>>        for (i = 0; i < TEST_PAGES; i++)
>>                numa_free(pages[i], onepage);
>>
>>        return 0;
>> }
>>
>> --
>> Thanks,
>> Zhouping
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at  http://www.tux.org/lkml/
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
> 


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Re: [LTP] mm: move_pages syscall can't return ENOENT when pages are not present

[Zhouping Liu]

----- Original Message -----
> From: "Wanlong Gao" <gaowanlong@cn.fujitsu.com>
> To: "Xiaotian Feng" <xtfeng@gmail.com>
> Cc: "Zhouping Liu" <zliu@redhat.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "LTP List"
> <ltp-list@lists.sourceforge.net>
> Sent: Wednesday, May 9, 2012 8:50:07 PM
> Subject: Re: mm: move_pages syscall can't return ENOENT when pages are not present
> 
> On 05/09/2012 05:28 PM, Xiaotian Feng wrote:
> 
> > On Wed, May 9, 2012 at 4:58 PM, Zhouping Liu <zliu@redhat.com>
> > wrote:
> >> hi, all
> >>
> >> Recently, I found an error in move_pages syscall:
> >>
> >> depending on move_pages(2), when page is not present,
> >> it should fail with ENOENT, in fact, it's ok without
> >> any errno.
> >>
> >> the following reproducer can easily reproduce
> >> the issue, suggest you get more details by strace.
> >> inside reproducer, I try to move a non-exist page from
> >> node 1 to node 0.
> >>
> >> I have tested it on the latest kernel 3.4-rc5 with 2 and 4 numa
> >> nodes.
> >> [zliu@ZhoupingLiu ~]$ gcc -o reproducer reproducer.c -lnuma
> >> [zliu@ZhoupingLiu ~]$ ./reproducer
> >> from_node is 1, to_node is 0
> >> ERROR: move_pages expected FAIL.
> >>
> > 
> > " If nodes is not NULL, move_pages returns the number of valid
> > migration requests which could not currently be performed.
> >  Otherwise
> > it returns 0."
> 
> 
> FYI, actually,
> commit e78bbfa8262424417a29349a8064a535053912b9
> Author: Brice Goglin <Brice.Goglin@inria.fr>
> Date:   Sat Oct 18 20:27:15 2008 -0700
> 
>     mm: stop returning -ENOENT from sys_move_pages() if nothing got
>     migrated

maybe you missed my thought :(
if I'm wrong, please correct me.

IMO, the issue is different with the patch.
apparently, in the case(reproducer), I tried to move 4 pages from node 1 to node 0,
and the 4th page is an invalid page(absent and not aligned)
     pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4 + 1;
but the reproducer passed with any errors, I think it's not common.

in the case, numa_free() return EINVAL, but we can't catch the err:
[root@ZhoupingLiu zliu]# strace ./reproducer 
...
move_pages(0, 4, {0x7f029c459000, 0x7f029c458000, 0x7f029c457000, 0x7f029c453001}, {0, 0, 0, 0}, {0xfffffffe, 0xfffffffe, 0xfffffffe, 0xfffffff2}, MPOL_MF_MOVE) = 0
write(1, "ERROR: move_pages expected FAIL."..., 33ERROR: move_pages expected FAIL.
) = 33
munmap(0x7f029c459000, 4096)            = 0
munmap(0x7f029c458000, 4096)            = 0
munmap(0x7f029c457000, 4096)            = 0
munmap(0x7f029c453001, 4096)            = -1 EINVAL (Invalid argument)
...

so I suggest we check pages' validity before move pages, if they are invalid, it should return
relevant error number to userspace, maybe it's other errno, not ENOENT, correct?

I'm trying to make a patch, but I'm a newer to the part :(

> 
> this commit changed the behaviour.
> 
> And the LTP has fixed to be consistent with this,
> https://github.com/linux-test-project/ltp/commit/338299da1ff27c7815183c1b07eb91e705f117ce
> 
> 
> Thanks,
> Wanlong Gao
> 
> > 
> >> I'm not in mail list, please CC me.
> >>
> >> /*
> >>  * Copyright (C) 2012  Red Hat, Inc.
> >>  *
> >>  * This work is licensed under the terms of the GNU GPL, version
> >>  2. See
> >>  * the COPYING file in the top-level directory.
> >>  *
> >>  * Compiled: gcc -o reproducer reproducer.c -lnuma
> >>  * Description:
> >>  * it's designed to check move_pages syscall, when
> >>  * page is not present, it should fail with ENOENT.
> >>  */
> >>
> >> #include <sys/mman.h>
> >> #include <sys/types.h>
> >> #include <sys/wait.h>
> >> #include <stdio.h>
> >> #include <unistd.h>
> >> #include <errno.h>
> >> #include <numa.h>
> >> #include <numaif.h>
> >>
> >> #define TEST_PAGES 4
> >>
> >> int main(int argc, char **argv)
> >> {
> >>        void *pages[TEST_PAGES];
> >>        int onepage;
> >>        int nodes[TEST_PAGES];
> >>        int status, ret;
> >>        int i, from_node = 1, to_node = 0;
> >>
> >>        onepage = getpagesize();
> >>
> >>        for (i = 0; i < TEST_PAGES - 1; i++) {
> >>                pages[i] = numa_alloc_onnode(onepage, from_node);
> >>                nodes[i] = to_node;
> >>        }
> >>
> >>        nodes[TEST_PAGES - 1] = to_node;
> >>
> >>        /*
> >>         * the follow page is not available, also not aligned,
> >>         * depend on move_pages(2), it can't be moved, and should
> >>         * return ENOENT errno.
> >>         */
> >>        pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4
> >>        + 1;
> >>
> >>        printf("from_node is %u, to_node is %u\n", from_node,
> >>        to_node);
> >>        ret = move_pages(0, TEST_PAGES, pages, nodes, &status,
> >>        MPOL_MF_MOVE);
> >>        if (ret == -1) {
> >>                if (errno != ENOENT)
> >>                        perror("move_pages expected ENOENT errno,
> >>                        but it's");
> >>                else
> >>                        printf("Succeed\n");
> >>        } else {
> >>                printf("ERROR: move_pages expected FAIL.\n");
> >>        }
> >>
> >>        for (i = 0; i < TEST_PAGES; i++)
> >>                numa_free(pages[i], onepage);
> >>
> >>        return 0;
> >> }
> >>
> >> --
> >> Thanks,
> >> Zhouping
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe
> >> linux-kernel" in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >> Please read the FAQ at  http://www.tux.org/lkml/
> > --
> > To unsubscribe from this list: send the line "unsubscribe
> > linux-kernel" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > Please read the FAQ at  http://www.tux.org/lkml/
> > 
> 
> 
> 

-- 
Thanks,
Zhouping

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Re: mm: move_pages syscall can't return ENOENT when pages are not present

[Zhouping Liu]

----- Original Message -----
> From: "Wanlong Gao" <gaowanlong@cn.fujitsu.com>
> To: "Xiaotian Feng" <xtfeng@gmail.com>
> Cc: "Zhouping Liu" <zliu@redhat.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "LTP List"
> <ltp-list@lists.sourceforge.net>
> Sent: Wednesday, May 9, 2012 8:50:07 PM
> Subject: Re: mm: move_pages syscall can't return ENOENT when pages are not present
> 
> On 05/09/2012 05:28 PM, Xiaotian Feng wrote:
> 
> > On Wed, May 9, 2012 at 4:58 PM, Zhouping Liu <zliu@redhat.com>
> > wrote:
> >> hi, all
> >>
> >> Recently, I found an error in move_pages syscall:
> >>
> >> depending on move_pages(2), when page is not present,
> >> it should fail with ENOENT, in fact, it's ok without
> >> any errno.
> >>
> >> the following reproducer can easily reproduce
> >> the issue, suggest you get more details by strace.
> >> inside reproducer, I try to move a non-exist page from
> >> node 1 to node 0.
> >>
> >> I have tested it on the latest kernel 3.4-rc5 with 2 and 4 numa
> >> nodes.
> >> [zliu@ZhoupingLiu ~]$ gcc -o reproducer reproducer.c -lnuma
> >> [zliu@ZhoupingLiu ~]$ ./reproducer
> >> from_node is 1, to_node is 0
> >> ERROR: move_pages expected FAIL.
> >>
> > 
> > " If nodes is not NULL, move_pages returns the number of valid
> > migration requests which could not currently be performed.
> >  Otherwise
> > it returns 0."
> 
> 
> FYI, actually,
> commit e78bbfa8262424417a29349a8064a535053912b9
> Author: Brice Goglin <Brice.Goglin@inria.fr>
> Date:   Sat Oct 18 20:27:15 2008 -0700
> 
>     mm: stop returning -ENOENT from sys_move_pages() if nothing got
>     migrated

maybe you missed my thought :(
if I'm wrong, please correct me.

IMO, the issue is different with the patch.
apparently, in the case(reproducer), I tried to move 4 pages from node 1 to node 0,
and the 4th page is an invalid page(absent and not aligned)
     pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4 + 1;
but the reproducer passed with any errors, I think it's not common.

in the case, numa_free() return EINVAL, but we can't catch the err:
[root@ZhoupingLiu zliu]# strace ./reproducer 
...
move_pages(0, 4, {0x7f029c459000, 0x7f029c458000, 0x7f029c457000, 0x7f029c453001}, {0, 0, 0, 0}, {0xfffffffe, 0xfffffffe, 0xfffffffe, 0xfffffff2}, MPOL_MF_MOVE) = 0
write(1, "ERROR: move_pages expected FAIL."..., 33ERROR: move_pages expected FAIL.
) = 33
munmap(0x7f029c459000, 4096)            = 0
munmap(0x7f029c458000, 4096)            = 0
munmap(0x7f029c457000, 4096)            = 0
munmap(0x7f029c453001, 4096)            = -1 EINVAL (Invalid argument)
...

so I suggest we check pages' validity before move pages, if they are invalid, it should return
relevant error number to userspace, maybe it's other errno, not ENOENT, correct?

I'm trying to make a patch, but I'm a newer to the part :(

> 
> this commit changed the behaviour.
> 
> And the LTP has fixed to be consistent with this,
> https://github.com/linux-test-project/ltp/commit/338299da1ff27c7815183c1b07eb91e705f117ce
> 
> 
> Thanks,
> Wanlong Gao
> 
> > 
> >> I'm not in mail list, please CC me.
> >>
> >> /*
> >>  * Copyright (C) 2012  Red Hat, Inc.
> >>  *
> >>  * This work is licensed under the terms of the GNU GPL, version
> >>  2. See
> >>  * the COPYING file in the top-level directory.
> >>  *
> >>  * Compiled: gcc -o reproducer reproducer.c -lnuma
> >>  * Description:
> >>  * it's designed to check move_pages syscall, when
> >>  * page is not present, it should fail with ENOENT.
> >>  */
> >>
> >> #include <sys/mman.h>
> >> #include <sys/types.h>
> >> #include <sys/wait.h>
> >> #include <stdio.h>
> >> #include <unistd.h>
> >> #include <errno.h>
> >> #include <numa.h>
> >> #include <numaif.h>
> >>
> >> #define TEST_PAGES 4
> >>
> >> int main(int argc, char **argv)
> >> {
> >>        void *pages[TEST_PAGES];
> >>        int onepage;
> >>        int nodes[TEST_PAGES];
> >>        int status, ret;
> >>        int i, from_node = 1, to_node = 0;
> >>
> >>        onepage = getpagesize();
> >>
> >>        for (i = 0; i < TEST_PAGES - 1; i++) {
> >>                pages[i] = numa_alloc_onnode(onepage, from_node);
> >>                nodes[i] = to_node;
> >>        }
> >>
> >>        nodes[TEST_PAGES - 1] = to_node;
> >>
> >>        /*
> >>         * the follow page is not available, also not aligned,
> >>         * depend on move_pages(2), it can't be moved, and should
> >>         * return ENOENT errno.
> >>         */
> >>        pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4
> >>        + 1;
> >>
> >>        printf("from_node is %u, to_node is %u\n", from_node,
> >>        to_node);
> >>        ret = move_pages(0, TEST_PAGES, pages, nodes, &status,
> >>        MPOL_MF_MOVE);
> >>        if (ret == -1) {
> >>                if (errno != ENOENT)
> >>                        perror("move_pages expected ENOENT errno,
> >>                        but it's");
> >>                else
> >>                        printf("Succeed\n");
> >>        } else {
> >>                printf("ERROR: move_pages expected FAIL.\n");
> >>        }
> >>
> >>        for (i = 0; i < TEST_PAGES; i++)
> >>                numa_free(pages[i], onepage);
> >>
> >>        return 0;
> >> }
> >>
> >> --
> >> Thanks,
> >> Zhouping
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe
> >> linux-kernel" in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >> Please read the FAQ at  http://www.tux.org/lkml/
> > --
> > To unsubscribe from this list: send the line "unsubscribe
> > linux-kernel" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > Please read the FAQ at  http://www.tux.org/lkml/
> > 
> 
> 
> 

-- 
Thanks,
Zhouping

Re: mm: move_pages syscall can't return ENOENT when pages are not present

[Zhouping Liu]

----- Original Message -----
> From: "Wanlong Gao" <gaowanlong@cn.fujitsu.com>
> To: "Xiaotian Feng" <xtfeng@gmail.com>
> Cc: "Zhouping Liu" <zliu@redhat.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "LTP List"
> <ltp-list@lists.sourceforge.net>
> Sent: Wednesday, May 9, 2012 8:50:07 PM
> Subject: Re: mm: move_pages syscall can't return ENOENT when pages are not present
> 
> On 05/09/2012 05:28 PM, Xiaotian Feng wrote:
> 
> > On Wed, May 9, 2012 at 4:58 PM, Zhouping Liu <zliu@redhat.com>
> > wrote:
> >> hi, all
> >>
> >> Recently, I found an error in move_pages syscall:
> >>
> >> depending on move_pages(2), when page is not present,
> >> it should fail with ENOENT, in fact, it's ok without
> >> any errno.
> >>
> >> the following reproducer can easily reproduce
> >> the issue, suggest you get more details by strace.
> >> inside reproducer, I try to move a non-exist page from
> >> node 1 to node 0.
> >>
> >> I have tested it on the latest kernel 3.4-rc5 with 2 and 4 numa
> >> nodes.
> >> [zliu@ZhoupingLiu ~]$ gcc -o reproducer reproducer.c -lnuma
> >> [zliu@ZhoupingLiu ~]$ ./reproducer
> >> from_node is 1, to_node is 0
> >> ERROR: move_pages expected FAIL.
> >>
> > 
> > " If nodes is not NULL, move_pages returns the number of valid
> > migration requests which could not currently be performed.
> >  Otherwise
> > it returns 0."
> 
> 
> FYI, actually,
> commit e78bbfa8262424417a29349a8064a535053912b9
> Author: Brice Goglin <Brice.Goglin@inria.fr>
> Date:   Sat Oct 18 20:27:15 2008 -0700
> 
>     mm: stop returning -ENOENT from sys_move_pages() if nothing got
>     migrated

maybe you missed my thought :(
if I'm wrong, please correct me.

IMO, the issue is different with the patch.
apparently, in the case(reproducer), I tried to move 4 pages from node 1 to node 0,
and the 4th page is an invalid page(absent and not aligned)
     pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4 + 1;
but the reproducer passed with any errors, I think it's not common.

in the case, numa_free() return EINVAL, but we can't catch the err:
[root@ZhoupingLiu zliu]# strace ./reproducer 
...
move_pages(0, 4, {0x7f029c459000, 0x7f029c458000, 0x7f029c457000, 0x7f029c453001}, {0, 0, 0, 0}, {0xfffffffe, 0xfffffffe, 0xfffffffe, 0xfffffff2}, MPOL_MF_MOVE) = 0
write(1, "ERROR: move_pages expected FAIL."..., 33ERROR: move_pages expected FAIL.
) = 33
munmap(0x7f029c459000, 4096)            = 0
munmap(0x7f029c458000, 4096)            = 0
munmap(0x7f029c457000, 4096)            = 0
munmap(0x7f029c453001, 4096)            = -1 EINVAL (Invalid argument)
...

so I suggest we check pages' validity before move pages, if they are invalid, it should return
relevant error number to userspace, maybe it's other errno, not ENOENT, correct?

I'm trying to make a patch, but I'm a newer to the part :(

> 
> this commit changed the behaviour.
> 
> And the LTP has fixed to be consistent with this,
> https://github.com/linux-test-project/ltp/commit/338299da1ff27c7815183c1b07eb91e705f117ce
> 
> 
> Thanks,
> Wanlong Gao
> 
> > 
> >> I'm not in mail list, please CC me.
> >>
> >> /*
> >>  * Copyright (C) 2012  Red Hat, Inc.
> >>  *
> >>  * This work is licensed under the terms of the GNU GPL, version
> >>  2. See
> >>  * the COPYING file in the top-level directory.
> >>  *
> >>  * Compiled: gcc -o reproducer reproducer.c -lnuma
> >>  * Description:
> >>  * it's designed to check move_pages syscall, when
> >>  * page is not present, it should fail with ENOENT.
> >>  */
> >>
> >> #include <sys/mman.h>
> >> #include <sys/types.h>
> >> #include <sys/wait.h>
> >> #include <stdio.h>
> >> #include <unistd.h>
> >> #include <errno.h>
> >> #include <numa.h>
> >> #include <numaif.h>
> >>
> >> #define TEST_PAGES 4
> >>
> >> int main(int argc, char **argv)
> >> {
> >>        void *pages[TEST_PAGES];
> >>        int onepage;
> >>        int nodes[TEST_PAGES];
> >>        int status, ret;
> >>        int i, from_node = 1, to_node = 0;
> >>
> >>        onepage = getpagesize();
> >>
> >>        for (i = 0; i < TEST_PAGES - 1; i++) {
> >>                pages[i] = numa_alloc_onnode(onepage, from_node);
> >>                nodes[i] = to_node;
> >>        }
> >>
> >>        nodes[TEST_PAGES - 1] = to_node;
> >>
> >>        /*
> >>         * the follow page is not available, also not aligned,
> >>         * depend on move_pages(2), it can't be moved, and should
> >>         * return ENOENT errno.
> >>         */
> >>        pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4
> >>        + 1;
> >>
> >>        printf("from_node is %u, to_node is %u\n", from_node,
> >>        to_node);
> >>        ret = move_pages(0, TEST_PAGES, pages, nodes, &status,
> >>        MPOL_MF_MOVE);
> >>        if (ret == -1) {
> >>                if (errno != ENOENT)
> >>                        perror("move_pages expected ENOENT errno,
> >>                        but it's");
> >>                else
> >>                        printf("Succeed\n");
> >>        } else {
> >>                printf("ERROR: move_pages expected FAIL.\n");
> >>        }
> >>
> >>        for (i = 0; i < TEST_PAGES; i++)
> >>                numa_free(pages[i], onepage);
> >>
> >>        return 0;
> >> }
> >>
> >> --
> >> Thanks,
> >> Zhouping
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe
> >> linux-kernel" in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >> Please read the FAQ at  http://www.tux.org/lkml/
> > --
> > To unsubscribe from this list: send the line "unsubscribe
> > linux-kernel" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > Please read the FAQ at  http://www.tux.org/lkml/
> > 
> 
> 
> 

-- 
Thanks,
Zhouping

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Re: [LTP] mm: move_pages syscall can't return ENOENT when pages are not present

[Wanlong Gao]

On 05/09/2012 09:33 PM, Zhouping Liu wrote:

> 
> 
> ----- Original Message -----
>> From: "Wanlong Gao" <gaowanlong@cn.fujitsu.com>
>> To: "Xiaotian Feng" <xtfeng@gmail.com>
>> Cc: "Zhouping Liu" <zliu@redhat.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "LTP List"
>> <ltp-list@lists.sourceforge.net>
>> Sent: Wednesday, May 9, 2012 8:50:07 PM
>> Subject: Re: mm: move_pages syscall can't return ENOENT when pages are not present
>>
>> On 05/09/2012 05:28 PM, Xiaotian Feng wrote:
>>
>>> On Wed, May 9, 2012 at 4:58 PM, Zhouping Liu <zliu@redhat.com>
>>> wrote:
>>>> hi, all
>>>>
>>>> Recently, I found an error in move_pages syscall:
>>>>
>>>> depending on move_pages(2), when page is not present,
>>>> it should fail with ENOENT, in fact, it's ok without
>>>> any errno.
>>>>
>>>> the following reproducer can easily reproduce
>>>> the issue, suggest you get more details by strace.
>>>> inside reproducer, I try to move a non-exist page from
>>>> node 1 to node 0.
>>>>
>>>> I have tested it on the latest kernel 3.4-rc5 with 2 and 4 numa
>>>> nodes.
>>>> [zliu@ZhoupingLiu ~]$ gcc -o reproducer reproducer.c -lnuma
>>>> [zliu@ZhoupingLiu ~]$ ./reproducer
>>>> from_node is 1, to_node is 0
>>>> ERROR: move_pages expected FAIL.
>>>>
>>>
>>> " If nodes is not NULL, move_pages returns the number of valid
>>> migration requests which could not currently be performed.
>>>  Otherwise
>>> it returns 0."
>>
>>
>> FYI, actually,
>> commit e78bbfa8262424417a29349a8064a535053912b9
>> Author: Brice Goglin <Brice.Goglin@inria.fr>
>> Date:   Sat Oct 18 20:27:15 2008 -0700
>>
>>     mm: stop returning -ENOENT from sys_move_pages() if nothing got
>>     migrated
> 
> maybe you missed my thought :(
> if I'm wrong, please correct me.
> 
> IMO, the issue is different with the patch.
> apparently, in the case(reproducer), I tried to move 4 pages from node 1 to node 0,
> and the 4th page is an invalid page(absent and not aligned)
>      pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4 + 1;
> but the reproducer passed with any errors, I think it's not common.
> 
> in the case, numa_free() return EINVAL, but we can't catch the err:


So, as Brice said, if you want to catch error, you should check your status array after
doing move_pages.


Thanks,
Wanlong Gao

> [root@ZhoupingLiu zliu]# strace ./reproducer 
> ...
> move_pages(0, 4, {0x7f029c459000, 0x7f029c458000, 0x7f029c457000, 0x7f029c453001}, {0, 0, 0, 0}, {0xfffffffe, 0xfffffffe, 0xfffffffe, 0xfffffff2}, MPOL_MF_MOVE) = 0
> write(1, "ERROR: move_pages expected FAIL."..., 33ERROR: move_pages expected FAIL.
> ) = 33
> munmap(0x7f029c459000, 4096)            = 0
> munmap(0x7f029c458000, 4096)            = 0
> munmap(0x7f029c457000, 4096)            = 0
> munmap(0x7f029c453001, 4096)            = -1 EINVAL (Invalid argument)
> ...
> 
> so I suggest we check pages' validity before move pages, if they are invalid, it should return
> relevant error number to userspace, maybe it's other errno, not ENOENT, correct?
> 
> I'm trying to make a patch, but I'm a newer to the part :(
> 
>>
>> this commit changed the behaviour.
>>
>> And the LTP has fixed to be consistent with this,
>> https://github.com/linux-test-project/ltp/commit/338299da1ff27c7815183c1b07eb91e705f117ce
>>
>>
>> Thanks,
>> Wanlong Gao
>>
>>>
>>>> I'm not in mail list, please CC me.
>>>>
>>>> /*
>>>>  * Copyright (C) 2012  Red Hat, Inc.
>>>>  *
>>>>  * This work is licensed under the terms of the GNU GPL, version
>>>>  2. See
>>>>  * the COPYING file in the top-level directory.
>>>>  *
>>>>  * Compiled: gcc -o reproducer reproducer.c -lnuma
>>>>  * Description:
>>>>  * it's designed to check move_pages syscall, when
>>>>  * page is not present, it should fail with ENOENT.
>>>>  */
>>>>
>>>> #include <sys/mman.h>
>>>> #include <sys/types.h>
>>>> #include <sys/wait.h>
>>>> #include <stdio.h>
>>>> #include <unistd.h>
>>>> #include <errno.h>
>>>> #include <numa.h>
>>>> #include <numaif.h>
>>>>
>>>> #define TEST_PAGES 4
>>>>
>>>> int main(int argc, char **argv)
>>>> {
>>>>        void *pages[TEST_PAGES];
>>>>        int onepage;
>>>>        int nodes[TEST_PAGES];
>>>>        int status, ret;
>>>>        int i, from_node = 1, to_node = 0;
>>>>
>>>>        onepage = getpagesize();
>>>>
>>>>        for (i = 0; i < TEST_PAGES - 1; i++) {
>>>>                pages[i] = numa_alloc_onnode(onepage, from_node);
>>>>                nodes[i] = to_node;
>>>>        }
>>>>
>>>>        nodes[TEST_PAGES - 1] = to_node;
>>>>
>>>>        /*
>>>>         * the follow page is not available, also not aligned,
>>>>         * depend on move_pages(2), it can't be moved, and should
>>>>         * return ENOENT errno.
>>>>         */
>>>>        pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4
>>>>        + 1;
>>>>
>>>>        printf("from_node is %u, to_node is %u\n", from_node,
>>>>        to_node);
>>>>        ret = move_pages(0, TEST_PAGES, pages, nodes, &status,
>>>>        MPOL_MF_MOVE);
>>>>        if (ret == -1) {
>>>>                if (errno != ENOENT)
>>>>                        perror("move_pages expected ENOENT errno,
>>>>                        but it's");
>>>>                else
>>>>                        printf("Succeed\n");
>>>>        } else {
>>>>                printf("ERROR: move_pages expected FAIL.\n");
>>>>        }
>>>>
>>>>        for (i = 0; i < TEST_PAGES; i++)
>>>>                numa_free(pages[i], onepage);
>>>>
>>>>        return 0;
>>>> }
>>>>
>>>> --
>>>> Thanks,
>>>> Zhouping
>>>> --
>>>> To unsubscribe from this list: send the line "unsubscribe
>>>> linux-kernel" in
>>>> the body of a message to majordomo@vger.kernel.org
>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>> Please read the FAQ at  http://www.tux.org/lkml/
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe
>>> linux-kernel" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>> Please read the FAQ at  http://www.tux.org/lkml/
>>>
>>
>>
>>
> 



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Re: mm: move_pages syscall can't return ENOENT when pages are not present

[Wanlong Gao]

On 05/09/2012 09:33 PM, Zhouping Liu wrote:

> 
> 
> ----- Original Message -----
>> From: "Wanlong Gao" <gaowanlong@cn.fujitsu.com>
>> To: "Xiaotian Feng" <xtfeng@gmail.com>
>> Cc: "Zhouping Liu" <zliu@redhat.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "LTP List"
>> <ltp-list@lists.sourceforge.net>
>> Sent: Wednesday, May 9, 2012 8:50:07 PM
>> Subject: Re: mm: move_pages syscall can't return ENOENT when pages are not present
>>
>> On 05/09/2012 05:28 PM, Xiaotian Feng wrote:
>>
>>> On Wed, May 9, 2012 at 4:58 PM, Zhouping Liu <zliu@redhat.com>
>>> wrote:
>>>> hi, all
>>>>
>>>> Recently, I found an error in move_pages syscall:
>>>>
>>>> depending on move_pages(2), when page is not present,
>>>> it should fail with ENOENT, in fact, it's ok without
>>>> any errno.
>>>>
>>>> the following reproducer can easily reproduce
>>>> the issue, suggest you get more details by strace.
>>>> inside reproducer, I try to move a non-exist page from
>>>> node 1 to node 0.
>>>>
>>>> I have tested it on the latest kernel 3.4-rc5 with 2 and 4 numa
>>>> nodes.
>>>> [zliu@ZhoupingLiu ~]$ gcc -o reproducer reproducer.c -lnuma
>>>> [zliu@ZhoupingLiu ~]$ ./reproducer
>>>> from_node is 1, to_node is 0
>>>> ERROR: move_pages expected FAIL.
>>>>
>>>
>>> " If nodes is not NULL, move_pages returns the number of valid
>>> migration requests which could not currently be performed.
>>>  Otherwise
>>> it returns 0."
>>
>>
>> FYI, actually,
>> commit e78bbfa8262424417a29349a8064a535053912b9
>> Author: Brice Goglin <Brice.Goglin@inria.fr>
>> Date:   Sat Oct 18 20:27:15 2008 -0700
>>
>>     mm: stop returning -ENOENT from sys_move_pages() if nothing got
>>     migrated
> 
> maybe you missed my thought :(
> if I'm wrong, please correct me.
> 
> IMO, the issue is different with the patch.
> apparently, in the case(reproducer), I tried to move 4 pages from node 1 to node 0,
> and the 4th page is an invalid page(absent and not aligned)
>      pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4 + 1;
> but the reproducer passed with any errors, I think it's not common.
> 
> in the case, numa_free() return EINVAL, but we can't catch the err:


So, as Brice said, if you want to catch error, you should check your status array after
doing move_pages.


Thanks,
Wanlong Gao

> [root@ZhoupingLiu zliu]# strace ./reproducer 
> ...
> move_pages(0, 4, {0x7f029c459000, 0x7f029c458000, 0x7f029c457000, 0x7f029c453001}, {0, 0, 0, 0}, {0xfffffffe, 0xfffffffe, 0xfffffffe, 0xfffffff2}, MPOL_MF_MOVE) = 0
> write(1, "ERROR: move_pages expected FAIL."..., 33ERROR: move_pages expected FAIL.
> ) = 33
> munmap(0x7f029c459000, 4096)            = 0
> munmap(0x7f029c458000, 4096)            = 0
> munmap(0x7f029c457000, 4096)            = 0
> munmap(0x7f029c453001, 4096)            = -1 EINVAL (Invalid argument)
> ...
> 
> so I suggest we check pages' validity before move pages, if they are invalid, it should return
> relevant error number to userspace, maybe it's other errno, not ENOENT, correct?
> 
> I'm trying to make a patch, but I'm a newer to the part :(
> 
>>
>> this commit changed the behaviour.
>>
>> And the LTP has fixed to be consistent with this,
>> https://github.com/linux-test-project/ltp/commit/338299da1ff27c7815183c1b07eb91e705f117ce
>>
>>
>> Thanks,
>> Wanlong Gao
>>
>>>
>>>> I'm not in mail list, please CC me.
>>>>
>>>> /*
>>>>  * Copyright (C) 2012  Red Hat, Inc.
>>>>  *
>>>>  * This work is licensed under the terms of the GNU GPL, version
>>>>  2. See
>>>>  * the COPYING file in the top-level directory.
>>>>  *
>>>>  * Compiled: gcc -o reproducer reproducer.c -lnuma
>>>>  * Description:
>>>>  * it's designed to check move_pages syscall, when
>>>>  * page is not present, it should fail with ENOENT.
>>>>  */
>>>>
>>>> #include <sys/mman.h>
>>>> #include <sys/types.h>
>>>> #include <sys/wait.h>
>>>> #include <stdio.h>
>>>> #include <unistd.h>
>>>> #include <errno.h>
>>>> #include <numa.h>
>>>> #include <numaif.h>
>>>>
>>>> #define TEST_PAGES 4
>>>>
>>>> int main(int argc, char **argv)
>>>> {
>>>>        void *pages[TEST_PAGES];
>>>>        int onepage;
>>>>        int nodes[TEST_PAGES];
>>>>        int status, ret;
>>>>        int i, from_node = 1, to_node = 0;
>>>>
>>>>        onepage = getpagesize();
>>>>
>>>>        for (i = 0; i < TEST_PAGES - 1; i++) {
>>>>                pages[i] = numa_alloc_onnode(onepage, from_node);
>>>>                nodes[i] = to_node;
>>>>        }
>>>>
>>>>        nodes[TEST_PAGES - 1] = to_node;
>>>>
>>>>        /*
>>>>         * the follow page is not available, also not aligned,
>>>>         * depend on move_pages(2), it can't be moved, and should
>>>>         * return ENOENT errno.
>>>>         */
>>>>        pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4
>>>>        + 1;
>>>>
>>>>        printf("from_node is %u, to_node is %u\n", from_node,
>>>>        to_node);
>>>>        ret = move_pages(0, TEST_PAGES, pages, nodes, &status,
>>>>        MPOL_MF_MOVE);
>>>>        if (ret == -1) {
>>>>                if (errno != ENOENT)
>>>>                        perror("move_pages expected ENOENT errno,
>>>>                        but it's");
>>>>                else
>>>>                        printf("Succeed\n");
>>>>        } else {
>>>>                printf("ERROR: move_pages expected FAIL.\n");
>>>>        }
>>>>
>>>>        for (i = 0; i < TEST_PAGES; i++)
>>>>                numa_free(pages[i], onepage);
>>>>
>>>>        return 0;
>>>> }
>>>>
>>>> --
>>>> Thanks,
>>>> Zhouping
>>>> --
>>>> To unsubscribe from this list: send the line "unsubscribe
>>>> linux-kernel" in
>>>> the body of a message to majordomo@vger.kernel.org
>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>> Please read the FAQ at  http://www.tux.org/lkml/
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe
>>> linux-kernel" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>> Please read the FAQ at  http://www.tux.org/lkml/
>>>
>>
>>
>>
> 

Re: mm: move_pages syscall can't return ENOENT when pages are not present

[Wanlong Gao]

On 05/09/2012 09:33 PM, Zhouping Liu wrote:

> 
> 
> ----- Original Message -----
>> From: "Wanlong Gao" <gaowanlong@cn.fujitsu.com>
>> To: "Xiaotian Feng" <xtfeng@gmail.com>
>> Cc: "Zhouping Liu" <zliu@redhat.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "LTP List"
>> <ltp-list@lists.sourceforge.net>
>> Sent: Wednesday, May 9, 2012 8:50:07 PM
>> Subject: Re: mm: move_pages syscall can't return ENOENT when pages are not present
>>
>> On 05/09/2012 05:28 PM, Xiaotian Feng wrote:
>>
>>> On Wed, May 9, 2012 at 4:58 PM, Zhouping Liu <zliu@redhat.com>
>>> wrote:
>>>> hi, all
>>>>
>>>> Recently, I found an error in move_pages syscall:
>>>>
>>>> depending on move_pages(2), when page is not present,
>>>> it should fail with ENOENT, in fact, it's ok without
>>>> any errno.
>>>>
>>>> the following reproducer can easily reproduce
>>>> the issue, suggest you get more details by strace.
>>>> inside reproducer, I try to move a non-exist page from
>>>> node 1 to node 0.
>>>>
>>>> I have tested it on the latest kernel 3.4-rc5 with 2 and 4 numa
>>>> nodes.
>>>> [zliu@ZhoupingLiu ~]$ gcc -o reproducer reproducer.c -lnuma
>>>> [zliu@ZhoupingLiu ~]$ ./reproducer
>>>> from_node is 1, to_node is 0
>>>> ERROR: move_pages expected FAIL.
>>>>
>>>
>>> " If nodes is not NULL, move_pages returns the number of valid
>>> migration requests which could not currently be performed.
>>>  Otherwise
>>> it returns 0."
>>
>>
>> FYI, actually,
>> commit e78bbfa8262424417a29349a8064a535053912b9
>> Author: Brice Goglin <Brice.Goglin@inria.fr>
>> Date:   Sat Oct 18 20:27:15 2008 -0700
>>
>>     mm: stop returning -ENOENT from sys_move_pages() if nothing got
>>     migrated
> 
> maybe you missed my thought :(
> if I'm wrong, please correct me.
> 
> IMO, the issue is different with the patch.
> apparently, in the case(reproducer), I tried to move 4 pages from node 1 to node 0,
> and the 4th page is an invalid page(absent and not aligned)
>      pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4 + 1;
> but the reproducer passed with any errors, I think it's not common.
> 
> in the case, numa_free() return EINVAL, but we can't catch the err:


So, as Brice said, if you want to catch error, you should check your status array after
doing move_pages.


Thanks,
Wanlong Gao

> [root@ZhoupingLiu zliu]# strace ./reproducer 
> ...
> move_pages(0, 4, {0x7f029c459000, 0x7f029c458000, 0x7f029c457000, 0x7f029c453001}, {0, 0, 0, 0}, {0xfffffffe, 0xfffffffe, 0xfffffffe, 0xfffffff2}, MPOL_MF_MOVE) = 0
> write(1, "ERROR: move_pages expected FAIL."..., 33ERROR: move_pages expected FAIL.
> ) = 33
> munmap(0x7f029c459000, 4096)            = 0
> munmap(0x7f029c458000, 4096)            = 0
> munmap(0x7f029c457000, 4096)            = 0
> munmap(0x7f029c453001, 4096)            = -1 EINVAL (Invalid argument)
> ...
> 
> so I suggest we check pages' validity before move pages, if they are invalid, it should return
> relevant error number to userspace, maybe it's other errno, not ENOENT, correct?
> 
> I'm trying to make a patch, but I'm a newer to the part :(
> 
>>
>> this commit changed the behaviour.
>>
>> And the LTP has fixed to be consistent with this,
>> https://github.com/linux-test-project/ltp/commit/338299da1ff27c7815183c1b07eb91e705f117ce
>>
>>
>> Thanks,
>> Wanlong Gao
>>
>>>
>>>> I'm not in mail list, please CC me.
>>>>
>>>> /*
>>>>  * Copyright (C) 2012  Red Hat, Inc.
>>>>  *
>>>>  * This work is licensed under the terms of the GNU GPL, version
>>>>  2. See
>>>>  * the COPYING file in the top-level directory.
>>>>  *
>>>>  * Compiled: gcc -o reproducer reproducer.c -lnuma
>>>>  * Description:
>>>>  * it's designed to check move_pages syscall, when
>>>>  * page is not present, it should fail with ENOENT.
>>>>  */
>>>>
>>>> #include <sys/mman.h>
>>>> #include <sys/types.h>
>>>> #include <sys/wait.h>
>>>> #include <stdio.h>
>>>> #include <unistd.h>
>>>> #include <errno.h>
>>>> #include <numa.h>
>>>> #include <numaif.h>
>>>>
>>>> #define TEST_PAGES 4
>>>>
>>>> int main(int argc, char **argv)
>>>> {
>>>>        void *pages[TEST_PAGES];
>>>>        int onepage;
>>>>        int nodes[TEST_PAGES];
>>>>        int status, ret;
>>>>        int i, from_node = 1, to_node = 0;
>>>>
>>>>        onepage = getpagesize();
>>>>
>>>>        for (i = 0; i < TEST_PAGES - 1; i++) {
>>>>                pages[i] = numa_alloc_onnode(onepage, from_node);
>>>>                nodes[i] = to_node;
>>>>        }
>>>>
>>>>        nodes[TEST_PAGES - 1] = to_node;
>>>>
>>>>        /*
>>>>         * the follow page is not available, also not aligned,
>>>>         * depend on move_pages(2), it can't be moved, and should
>>>>         * return ENOENT errno.
>>>>         */
>>>>        pages[TEST_PAGES - 1] = pages[TEST_PAGES - 2] - onepage * 4
>>>>        + 1;
>>>>
>>>>        printf("from_node is %u, to_node is %u\n", from_node,
>>>>        to_node);
>>>>        ret = move_pages(0, TEST_PAGES, pages, nodes, &status,
>>>>        MPOL_MF_MOVE);
>>>>        if (ret == -1) {
>>>>                if (errno != ENOENT)
>>>>                        perror("move_pages expected ENOENT errno,
>>>>                        but it's");
>>>>                else
>>>>                        printf("Succeed\n");
>>>>        } else {
>>>>                printf("ERROR: move_pages expected FAIL.\n");
>>>>        }
>>>>
>>>>        for (i = 0; i < TEST_PAGES; i++)
>>>>                numa_free(pages[i], onepage);
>>>>
>>>>        return 0;
>>>> }
>>>>
>>>> --
>>>> Thanks,
>>>> Zhouping
>>>> --
>>>> To unsubscribe from this list: send the line "unsubscribe
>>>> linux-kernel" in
>>>> the body of a message to majordomo@vger.kernel.org
>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>> Please read the FAQ at  http://www.tux.org/lkml/
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe
>>> linux-kernel" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>> Please read the FAQ at  http://www.tux.org/lkml/
>>>
>>
>>
>>
> 


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Re: mm: move_pages syscall can't return ENOENT when pages are not present

[Brice Goglin]

Le 09/05/2012 10:58, Zhouping Liu a A(C)crit :
> hi, all
>
> Recently, I found an error in move_pages syscall:
>
> depending on move_pages(2), when page is not present,
> it should fail with ENOENT, in fact, it's ok without
> any errno.
>
> the following reproducer can easily reproduce
> the issue, suggest you get more details by strace.
> inside reproducer, I try to move a non-exist page from
> node 1 to node 0.
>

If I understand correctly, 3 pages should migrate properly but the last
one cannot migrate because it's not present. In this case, move_pages
returns success. -ENOENT is set in the status array, not in the return
value/errno.

In the past, if *all* pages failed to migrate, move_pages would return
ENOENT instead of success, but the behavior was inconsistent so I
changed that in commit e78bbfa8262424417a29349a8064a535053912b9 as
Wanlong Gao said. But that should not matter here since 3 pages out of 4
are successfully migrated from what I understand.

The manpage should be updated (remove ENOENT from the ERRORS section,
but keep it in the "Page states in the status array" section).

Brice

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
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Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: mm: move_pages syscall can't return ENOENT when pages are not present

[Brice Goglin]

Le 09/05/2012 10:58, Zhouping Liu a écrit :
> hi, all
>
> Recently, I found an error in move_pages syscall:
>
> depending on move_pages(2), when page is not present,
> it should fail with ENOENT, in fact, it's ok without
> any errno.
>
> the following reproducer can easily reproduce
> the issue, suggest you get more details by strace.
> inside reproducer, I try to move a non-exist page from
> node 1 to node 0.
>

If I understand correctly, 3 pages should migrate properly but the last
one cannot migrate because it's not present. In this case, move_pages
returns success. -ENOENT is set in the status array, not in the return
value/errno.

In the past, if *all* pages failed to migrate, move_pages would return
ENOENT instead of success, but the behavior was inconsistent so I
changed that in commit e78bbfa8262424417a29349a8064a535053912b9 as
Wanlong Gao said. But that should not matter here since 3 pages out of 4
are successfully migrated from what I understand.

The manpage should be updated (remove ENOENT from the ERRORS section,
but keep it in the "Page states in the status array" section).

Brice