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From: Oleksandr Natalenko <oleksandr@redhat.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-mm <linux-mm@kvack.org>, Michal Hocko <mhocko@suse.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Tim Murray <timmurray@google.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	Suren Baghdasaryan <surenb@google.com>,
	Daniel Colascione <dancol@google.com>,
	Shakeel Butt <shakeelb@google.com>,
	Sonny Rao <sonnyrao@google.com>,
	Brian Geffon <bgeffon@google.com>
Subject: Re: [RFC 4/7] mm: factor out madvise's core functionality
Date: Mon, 20 May 2019 16:26:33 +0200
Message-ID: <20190520142633.x5d27gk454qruc4o@butterfly.localdomain> (raw)
In-Reply-To: <20190520035254.57579-5-minchan@kernel.org>

Hi.

On Mon, May 20, 2019 at 12:52:51PM +0900, Minchan Kim wrote:
> This patch factor out madvise's core functionality so that upcoming
> patch can reuse it without duplication.
> 
> It shouldn't change any behavior.
> 
> Signed-off-by: Minchan Kim <minchan@kernel.org>
> ---
>  mm/madvise.c | 168 +++++++++++++++++++++++++++------------------------
>  1 file changed, 89 insertions(+), 79 deletions(-)
> 
> diff --git a/mm/madvise.c b/mm/madvise.c
> index 9a6698b56845..119e82e1f065 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -742,7 +742,8 @@ static long madvise_dontneed_single_vma(struct vm_area_struct *vma,
>  	return 0;
>  }
>  
> -static long madvise_dontneed_free(struct vm_area_struct *vma,
> +static long madvise_dontneed_free(struct task_struct *tsk,
> +				  struct vm_area_struct *vma,
>  				  struct vm_area_struct **prev,
>  				  unsigned long start, unsigned long end,
>  				  int behavior)
> @@ -754,8 +755,8 @@ static long madvise_dontneed_free(struct vm_area_struct *vma,
>  	if (!userfaultfd_remove(vma, start, end)) {
>  		*prev = NULL; /* mmap_sem has been dropped, prev is stale */
>  
> -		down_read(&current->mm->mmap_sem);
> -		vma = find_vma(current->mm, start);
> +		down_read(&tsk->mm->mmap_sem);
> +		vma = find_vma(tsk->mm, start);
>  		if (!vma)
>  			return -ENOMEM;
>  		if (start < vma->vm_start) {
> @@ -802,7 +803,8 @@ static long madvise_dontneed_free(struct vm_area_struct *vma,
>   * Application wants to free up the pages and associated backing store.
>   * This is effectively punching a hole into the middle of a file.
>   */
> -static long madvise_remove(struct vm_area_struct *vma,
> +static long madvise_remove(struct task_struct *tsk,
> +				struct vm_area_struct *vma,
>  				struct vm_area_struct **prev,
>  				unsigned long start, unsigned long end)
>  {
> @@ -836,13 +838,13 @@ static long madvise_remove(struct vm_area_struct *vma,
>  	get_file(f);
>  	if (userfaultfd_remove(vma, start, end)) {
>  		/* mmap_sem was not released by userfaultfd_remove() */
> -		up_read(&current->mm->mmap_sem);
> +		up_read(&tsk->mm->mmap_sem);
>  	}
>  	error = vfs_fallocate(f,
>  				FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
>  				offset, end - start);
>  	fput(f);
> -	down_read(&current->mm->mmap_sem);
> +	down_read(&tsk->mm->mmap_sem);
>  	return error;
>  }
>  
> @@ -916,12 +918,13 @@ static int madvise_inject_error(int behavior,
>  #endif

What about madvise_inject_error() and get_user_pages_fast() in it
please?

>  
>  static long
> -madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
> -		unsigned long start, unsigned long end, int behavior)
> +madvise_vma(struct task_struct *tsk, struct vm_area_struct *vma,
> +		struct vm_area_struct **prev, unsigned long start,
> +		unsigned long end, int behavior)
>  {
>  	switch (behavior) {
>  	case MADV_REMOVE:
> -		return madvise_remove(vma, prev, start, end);
> +		return madvise_remove(tsk, vma, prev, start, end);
>  	case MADV_WILLNEED:
>  		return madvise_willneed(vma, prev, start, end);
>  	case MADV_COOL:
> @@ -930,7 +933,8 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
>  		return madvise_cold(vma, start, end);
>  	case MADV_FREE:
>  	case MADV_DONTNEED:
> -		return madvise_dontneed_free(vma, prev, start, end, behavior);
> +		return madvise_dontneed_free(tsk, vma, prev, start,
> +						end, behavior);
>  	default:
>  		return madvise_behavior(vma, prev, start, end, behavior);
>  	}
> @@ -974,68 +978,8 @@ madvise_behavior_valid(int behavior)
>  	}
>  }
>  
> -/*
> - * The madvise(2) system call.
> - *
> - * Applications can use madvise() to advise the kernel how it should
> - * handle paging I/O in this VM area.  The idea is to help the kernel
> - * use appropriate read-ahead and caching techniques.  The information
> - * provided is advisory only, and can be safely disregarded by the
> - * kernel without affecting the correct operation of the application.
> - *
> - * behavior values:
> - *  MADV_NORMAL - the default behavior is to read clusters.  This
> - *		results in some read-ahead and read-behind.
> - *  MADV_RANDOM - the system should read the minimum amount of data
> - *		on any access, since it is unlikely that the appli-
> - *		cation will need more than what it asks for.
> - *  MADV_SEQUENTIAL - pages in the given range will probably be accessed
> - *		once, so they can be aggressively read ahead, and
> - *		can be freed soon after they are accessed.
> - *  MADV_WILLNEED - the application is notifying the system to read
> - *		some pages ahead.
> - *  MADV_DONTNEED - the application is finished with the given range,
> - *		so the kernel can free resources associated with it.
> - *  MADV_FREE - the application marks pages in the given range as lazy free,
> - *		where actual purges are postponed until memory pressure happens.
> - *  MADV_REMOVE - the application wants to free up the given range of
> - *		pages and associated backing store.
> - *  MADV_DONTFORK - omit this area from child's address space when forking:
> - *		typically, to avoid COWing pages pinned by get_user_pages().
> - *  MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking.
> - *  MADV_WIPEONFORK - present the child process with zero-filled memory in this
> - *              range after a fork.
> - *  MADV_KEEPONFORK - undo the effect of MADV_WIPEONFORK
> - *  MADV_HWPOISON - trigger memory error handler as if the given memory range
> - *		were corrupted by unrecoverable hardware memory failure.
> - *  MADV_SOFT_OFFLINE - try to soft-offline the given range of memory.
> - *  MADV_MERGEABLE - the application recommends that KSM try to merge pages in
> - *		this area with pages of identical content from other such areas.
> - *  MADV_UNMERGEABLE- cancel MADV_MERGEABLE: no longer merge pages with others.
> - *  MADV_HUGEPAGE - the application wants to back the given range by transparent
> - *		huge pages in the future. Existing pages might be coalesced and
> - *		new pages might be allocated as THP.
> - *  MADV_NOHUGEPAGE - mark the given range as not worth being backed by
> - *		transparent huge pages so the existing pages will not be
> - *		coalesced into THP and new pages will not be allocated as THP.
> - *  MADV_DONTDUMP - the application wants to prevent pages in the given range
> - *		from being included in its core dump.
> - *  MADV_DODUMP - cancel MADV_DONTDUMP: no longer exclude from core dump.
> - *
> - * return values:
> - *  zero    - success
> - *  -EINVAL - start + len < 0, start is not page-aligned,
> - *		"behavior" is not a valid value, or application
> - *		is attempting to release locked or shared pages,
> - *		or the specified address range includes file, Huge TLB,
> - *		MAP_SHARED or VMPFNMAP range.
> - *  -ENOMEM - addresses in the specified range are not currently
> - *		mapped, or are outside the AS of the process.
> - *  -EIO    - an I/O error occurred while paging in data.
> - *  -EBADF  - map exists, but area maps something that isn't a file.
> - *  -EAGAIN - a kernel resource was temporarily unavailable.
> - */
> -SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
> +static int madvise_core(struct task_struct *tsk, unsigned long start,
> +			size_t len_in, int behavior)
>  {
>  	unsigned long end, tmp;
>  	struct vm_area_struct *vma, *prev;
> @@ -1071,10 +1015,10 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
>  
>  	write = madvise_need_mmap_write(behavior);
>  	if (write) {
> -		if (down_write_killable(&current->mm->mmap_sem))
> +		if (down_write_killable(&tsk->mm->mmap_sem))
>  			return -EINTR;
>  	} else {
> -		down_read(&current->mm->mmap_sem);
> +		down_read(&tsk->mm->mmap_sem);
>  	}
>  
>  	/*
> @@ -1082,7 +1026,7 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
>  	 * ranges, just ignore them, but return -ENOMEM at the end.
>  	 * - different from the way of handling in mlock etc.
>  	 */
> -	vma = find_vma_prev(current->mm, start, &prev);
> +	vma = find_vma_prev(tsk->mm, start, &prev);
>  	if (vma && start > vma->vm_start)
>  		prev = vma;
>  
> @@ -1107,7 +1051,7 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
>  			tmp = end;
>  
>  		/* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */
> -		error = madvise_vma(vma, &prev, start, tmp, behavior);
> +		error = madvise_vma(tsk, vma, &prev, start, tmp, behavior);
>  		if (error)
>  			goto out;
>  		start = tmp;
> @@ -1119,14 +1063,80 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
>  		if (prev)
>  			vma = prev->vm_next;
>  		else	/* madvise_remove dropped mmap_sem */
> -			vma = find_vma(current->mm, start);
> +			vma = find_vma(tsk->mm, start);
>  	}
>  out:
>  	blk_finish_plug(&plug);
>  	if (write)
> -		up_write(&current->mm->mmap_sem);
> +		up_write(&tsk->mm->mmap_sem);
>  	else
> -		up_read(&current->mm->mmap_sem);
> +		up_read(&tsk->mm->mmap_sem);
>  
>  	return error;
>  }
> +
> +/*
> + * The madvise(2) system call.
> + *
> + * Applications can use madvise() to advise the kernel how it should
> + * handle paging I/O in this VM area.  The idea is to help the kernel
> + * use appropriate read-ahead and caching techniques.  The information
> + * provided is advisory only, and can be safely disregarded by the
> + * kernel without affecting the correct operation of the application.
> + *
> + * behavior values:
> + *  MADV_NORMAL - the default behavior is to read clusters.  This
> + *		results in some read-ahead and read-behind.
> + *  MADV_RANDOM - the system should read the minimum amount of data
> + *		on any access, since it is unlikely that the appli-
> + *		cation will need more than what it asks for.
> + *  MADV_SEQUENTIAL - pages in the given range will probably be accessed
> + *		once, so they can be aggressively read ahead, and
> + *		can be freed soon after they are accessed.
> + *  MADV_WILLNEED - the application is notifying the system to read
> + *		some pages ahead.
> + *  MADV_DONTNEED - the application is finished with the given range,
> + *		so the kernel can free resources associated with it.
> + *  MADV_FREE - the application marks pages in the given range as lazy free,
> + *		where actual purges are postponed until memory pressure happens.
> + *  MADV_REMOVE - the application wants to free up the given range of
> + *		pages and associated backing store.
> + *  MADV_DONTFORK - omit this area from child's address space when forking:
> + *		typically, to avoid COWing pages pinned by get_user_pages().
> + *  MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking.
> + *  MADV_WIPEONFORK - present the child process with zero-filled memory in this
> + *              range after a fork.
> + *  MADV_KEEPONFORK - undo the effect of MADV_WIPEONFORK
> + *  MADV_HWPOISON - trigger memory error handler as if the given memory range
> + *		were corrupted by unrecoverable hardware memory failure.
> + *  MADV_SOFT_OFFLINE - try to soft-offline the given range of memory.
> + *  MADV_MERGEABLE - the application recommends that KSM try to merge pages in
> + *		this area with pages of identical content from other such areas.
> + *  MADV_UNMERGEABLE- cancel MADV_MERGEABLE: no longer merge pages with others.
> + *  MADV_HUGEPAGE - the application wants to back the given range by transparent
> + *		huge pages in the future. Existing pages might be coalesced and
> + *		new pages might be allocated as THP.
> + *  MADV_NOHUGEPAGE - mark the given range as not worth being backed by
> + *		transparent huge pages so the existing pages will not be
> + *		coalesced into THP and new pages will not be allocated as THP.
> + *  MADV_DONTDUMP - the application wants to prevent pages in the given range
> + *		from being included in its core dump.
> + *  MADV_DODUMP - cancel MADV_DONTDUMP: no longer exclude from core dump.
> + *
> + * return values:
> + *  zero    - success
> + *  -EINVAL - start + len < 0, start is not page-aligned,
> + *		"behavior" is not a valid value, or application
> + *		is attempting to release locked or shared pages,
> + *		or the specified address range includes file, Huge TLB,
> + *		MAP_SHARED or VMPFNMAP range.
> + *  -ENOMEM - addresses in the specified range are not currently
> + *		mapped, or are outside the AS of the process.
> + *  -EIO    - an I/O error occurred while paging in data.
> + *  -EBADF  - map exists, but area maps something that isn't a file.
> + *  -EAGAIN - a kernel resource was temporarily unavailable.
> + */
> +SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
> +{
> +	return madvise_core(current, start, len_in, behavior);
> +}
> -- 
> 2.21.0.1020.gf2820cf01a-goog
> 

-- 
  Best regards,
    Oleksandr Natalenko (post-factum)
    Senior Software Maintenance Engineer


  reply index

Thread overview: 138+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-20  3:52 [RFC 0/7] introduce memory hinting API for external process Minchan Kim
2019-05-20  3:52 ` [RFC 1/7] mm: introduce MADV_COOL Minchan Kim
2019-05-20  8:16   ` Michal Hocko
2019-05-20  8:19     ` Michal Hocko
2019-05-20 15:08       ` Suren Baghdasaryan
2019-05-20 22:55       ` Minchan Kim
2019-05-20 22:54     ` Minchan Kim
2019-05-21  6:04       ` Michal Hocko
2019-05-21  9:11         ` Minchan Kim
2019-05-21 10:05           ` Michal Hocko
2019-05-28  8:53   ` Hillf Danton
2019-05-28 10:58   ` Minchan Kim
2019-05-20  3:52 ` [RFC 2/7] mm: change PAGEREF_RECLAIM_CLEAN with PAGE_REFRECLAIM Minchan Kim
2019-05-20 16:50   ` Johannes Weiner
2019-05-20 22:57     ` Minchan Kim
2019-05-20  3:52 ` [RFC 3/7] mm: introduce MADV_COLD Minchan Kim
2019-05-20  8:27   ` Michal Hocko
2019-05-20 23:00     ` Minchan Kim
2019-05-21  6:08       ` Michal Hocko
2019-05-21  9:13         ` Minchan Kim
2019-05-28 14:54   ` Hillf Danton
2019-05-30  0:45   ` Minchan Kim
2019-05-20  3:52 ` [RFC 4/7] mm: factor out madvise's core functionality Minchan Kim
2019-05-20 14:26   ` Oleksandr Natalenko [this message]
2019-05-21  1:26     ` Minchan Kim
2019-05-21  6:36       ` Oleksandr Natalenko
2019-05-21  6:50         ` Michal Hocko
2019-05-21  7:06           ` Oleksandr Natalenko
2019-05-21 10:52             ` Minchan Kim
2019-05-21 11:00               ` Michal Hocko
2019-05-21 11:24                 ` Minchan Kim
2019-05-21 11:32                   ` Michal Hocko
2019-05-21 10:49         ` Minchan Kim
2019-05-21 10:55           ` Michal Hocko
2019-05-20  3:52 ` [RFC 5/7] mm: introduce external memory hinting API Minchan Kim
2019-05-20  9:18   ` Michal Hocko
2019-05-21  2:41     ` Minchan Kim
2019-05-21  6:17       ` Michal Hocko
2019-05-21 10:32         ` Minchan Kim
2019-05-21  9:01   ` Christian Brauner
2019-05-21 11:35     ` Minchan Kim
2019-05-21 11:51       ` Christian Brauner
2019-05-21 15:31   ` Oleg Nesterov
2019-05-27  7:43     ` Minchan Kim
2019-05-27 15:12       ` Oleg Nesterov
2019-05-27 23:33         ` Minchan Kim
2019-05-28  7:23           ` Michal Hocko
2019-05-29  3:41   ` Hillf Danton
2019-05-30  0:38   ` Minchan Kim
2019-05-20  3:52 ` [RFC 6/7] mm: extend process_madvise syscall to support vector arrary Minchan Kim
2019-05-20  9:22   ` Michal Hocko
2019-05-21  2:48     ` Minchan Kim
2019-05-21  6:24       ` Michal Hocko
2019-05-21 10:26         ` Minchan Kim
2019-05-21 10:37           ` Michal Hocko
2019-05-27  7:49             ` Minchan Kim
2019-05-29 10:08               ` Daniel Colascione
2019-05-29 10:33                 ` Michal Hocko
2019-05-30  2:17                   ` Minchan Kim
2019-05-30  6:57                     ` Michal Hocko
2019-05-30  8:02                       ` Minchan Kim
2019-05-30 16:19                         ` Daniel Colascione
2019-05-30 18:47                         ` Michal Hocko
2019-05-29  4:14   ` Hillf Danton
2019-05-30  0:35   ` Minchan Kim
2019-05-20  3:52 ` [RFC 7/7] mm: madvise support MADV_ANONYMOUS_FILTER and MADV_FILE_FILTER Minchan Kim
2019-05-20  9:28   ` Michal Hocko
2019-05-21  2:55     ` Minchan Kim
2019-05-21  6:26       ` Michal Hocko
2019-05-27  7:58         ` Minchan Kim
2019-05-27 12:44           ` Michal Hocko
2019-05-28  3:26             ` Minchan Kim
2019-05-28  6:29               ` Michal Hocko
2019-05-28  8:13                 ` Minchan Kim
2019-05-28  8:31                   ` Daniel Colascione
2019-05-28  8:49                     ` Minchan Kim
2019-05-28  9:08                       ` Michal Hocko
2019-05-28  9:39                         ` Daniel Colascione
2019-05-28 10:33                           ` Michal Hocko
2019-05-28 11:21                             ` Daniel Colascione
2019-05-28 11:49                               ` Michal Hocko
2019-05-28 12:11                                 ` Daniel Colascione
2019-05-28 12:32                                   ` Michal Hocko
2019-05-28 10:32                         ` Minchan Kim
2019-05-28 10:41                           ` Michal Hocko
2019-05-28 11:12                             ` Minchan Kim
2019-05-28 11:28                               ` Michal Hocko
2019-05-28 11:42                                 ` Daniel Colascione
2019-05-28 11:56                                   ` Michal Hocko
2019-05-28 12:18                                     ` Daniel Colascione
2019-05-28 12:38                                       ` Michal Hocko
2019-05-28 12:10                                   ` Minchan Kim
2019-05-28 11:44                                 ` Minchan Kim
2019-05-28 11:51                                   ` Daniel Colascione
2019-05-28 12:06                                   ` Michal Hocko
2019-05-28 12:22                                     ` Minchan Kim
2019-05-28 11:28                             ` Daniel Colascione
2019-05-21 15:33       ` Johannes Weiner
2019-05-22  1:50         ` Minchan Kim
2019-05-29  4:36   ` Hillf Danton
2019-05-30  1:00   ` Minchan Kim
2019-05-20  6:37 ` [RFC 0/7] introduce memory hinting API for external process Anshuman Khandual
2019-05-20 16:59   ` Tim Murray
2019-05-21  2:55     ` Anshuman Khandual
2019-05-21  5:14       ` Minchan Kim
2019-05-21 10:34       ` Michal Hocko
2019-05-28 10:50         ` Anshuman Khandual
2019-05-21 12:56       ` Shakeel Butt
2019-05-22  4:15         ` Brian Geffon
2019-05-22  4:23         ` Brian Geffon
2019-05-20  9:28 ` Michal Hocko
2019-05-20 14:42 ` Oleksandr Natalenko
2019-05-21  2:56   ` Minchan Kim
2019-05-20 16:46 ` Johannes Weiner
2019-05-21  4:39   ` Minchan Kim
2019-05-21  6:32     ` Michal Hocko
2019-05-21  1:44 ` Matthew Wilcox
2019-05-21  5:01   ` Minchan Kim
2019-05-21  6:34   ` Michal Hocko
2019-05-21  8:42 ` Christian Brauner
2019-05-21 11:05   ` Minchan Kim
2019-05-21 11:30     ` Christian Brauner
2019-05-21 11:39       ` Christian Brauner
2019-05-22  5:11         ` Daniel Colascione
2019-05-22  8:22           ` Christian Brauner
2019-05-22 13:16             ` Daniel Colascione
2019-05-22 14:52               ` Christian Brauner
2019-05-22 15:17                 ` Daniel Colascione
2019-05-22 15:48                   ` Christian Brauner
2019-05-22 15:57                     ` Daniel Colascione
2019-05-22 16:01                       ` Christian Brauner
2019-05-22 16:01                         ` Daniel Colascione
2019-05-23 13:07                           ` Minchan Kim
2019-05-27  8:06                             ` Minchan Kim
2019-05-21 11:41       ` Minchan Kim
2019-05-21 12:04         ` Christian Brauner
2019-05-21 12:15           ` Oleksandr Natalenko
2019-05-21 12:53 ` Shakeel Butt

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Linux-mm Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-mm/0 linux-mm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-mm linux-mm/ https://lore.kernel.org/linux-mm \
		linux-mm@kvack.org
	public-inbox-index linux-mm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kvack.linux-mm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git