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From: Andrea Arcangeli <aarcange@redhat.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Michel Lespinasse <walken@google.com>,
	Andrew Jones <drjones@redhat.com>,
	Hugh Dickins <hughd@google.com>, Mel Gorman <mgorman@suse.de>,
	Andres Lagar-Cavilla <andreslc@google.com>,
	Minchan Kim <minchan@kernel.org>,
	KOSAKI Motohiro <kosaki.motohiro@gmail.com>,
	"\\\"Dr. David Alan Gilbert\\\"" <dgilbert@redhat.com>,
	Peter Feiner <pfeiner@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	James Bottomley <James.Bottomley@HansenPartnership.com>,
	David Miller <davem@davemloft.net>,
	Steve Capper <steve.capper@linaro.org>,
	Johannes Weiner <jweiner@redhat.com>
Subject: Re: [PATCH 2/5] mm: gup: add __get_user_pages_unlocked to customize gup_flags
Date: Thu, 30 Oct 2014 18:43:09 +0100	[thread overview]
Message-ID: <20141030174309.GL19606@redhat.com> (raw)
In-Reply-To: <20141030121737.GB31134@node.dhcp.inet.fi>

On Thu, Oct 30, 2014 at 02:17:37PM +0200, Kirill A. Shutemov wrote:
> On Wed, Oct 29, 2014 at 05:35:17PM +0100, Andrea Arcangeli wrote:
> > diff --git a/mm/gup.c b/mm/gup.c
> > index a8521f1..01534ff 100644
> > --- a/mm/gup.c
> > +++ b/mm/gup.c
> > @@ -591,9 +591,9 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
> >  						int write, int force,
> >  						struct page **pages,
> >  						struct vm_area_struct **vmas,
> > -						int *locked, bool notify_drop)
> > +						int *locked, bool notify_drop,
> > +						unsigned int flags)
> 
> Argument list getting too long. Should we consider packing them into a
> struct?

It's __always_inline, so it's certainly not a runtime concern. The
whole point of using __always_inline is to optimize away certain
branches at build time.

If this about cleaning it up and not for changing the runtime (which I
think couldn't get any better because of the __always_inline), we
should at least make certain gcc can still see through the structure
offsets to delete the same code blocks at build time if possible,
before doing the change.

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WARNING: multiple messages have this Message-ID (diff)
From: Andrea Arcangeli <aarcange@redhat.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Michel Lespinasse <walken@google.com>,
	Andrew Jones <drjones@redhat.com>,
	Hugh Dickins <hughd@google.com>, Mel Gorman <mgorman@suse.de>,
	Andres Lagar-Cavilla <andreslc@google.com>,
	Minchan Kim <minchan@kernel.org>,
	KOSAKI Motohiro <kosaki.motohiro@gmail.com>,
	"\\\"Dr. David Alan Gilbert\\\"" <dgilbert@redhat.com>,
	Peter Feiner <pfeiner@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	James Bottomley <James.Bottomley@HansenPartnership.com>,
	David Miller <davem@davemloft.net>,
	Steve Capper <steve.capper@linaro.org>,
	Johannes Weiner <jweiner@redhat.com>
Subject: Re: [PATCH 2/5] mm: gup: add __get_user_pages_unlocked to customize gup_flags
Date: Thu, 30 Oct 2014 18:43:09 +0100	[thread overview]
Message-ID: <20141030174309.GL19606@redhat.com> (raw)
In-Reply-To: <20141030121737.GB31134@node.dhcp.inet.fi>

On Thu, Oct 30, 2014 at 02:17:37PM +0200, Kirill A. Shutemov wrote:
> On Wed, Oct 29, 2014 at 05:35:17PM +0100, Andrea Arcangeli wrote:
> > diff --git a/mm/gup.c b/mm/gup.c
> > index a8521f1..01534ff 100644
> > --- a/mm/gup.c
> > +++ b/mm/gup.c
> > @@ -591,9 +591,9 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
> >  						int write, int force,
> >  						struct page **pages,
> >  						struct vm_area_struct **vmas,
> > -						int *locked, bool notify_drop)
> > +						int *locked, bool notify_drop,
> > +						unsigned int flags)
> 
> Argument list getting too long. Should we consider packing them into a
> struct?

It's __always_inline, so it's certainly not a runtime concern. The
whole point of using __always_inline is to optimize away certain
branches at build time.

If this about cleaning it up and not for changing the runtime (which I
think couldn't get any better because of the __always_inline), we
should at least make certain gcc can still see through the structure
offsets to delete the same code blocks at build time if possible,
before doing the change.

  reply	other threads:[~2014-10-30 17:43 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-29 16:35 [PATCH 0/5] get_user_pages_locked|unlocked v1 Andrea Arcangeli
2014-10-29 16:35 ` Andrea Arcangeli
2014-10-29 16:35 ` [PATCH 1/5] mm: gup: add get_user_pages_locked and get_user_pages_unlocked Andrea Arcangeli
2014-10-29 16:35   ` Andrea Arcangeli
2014-10-30 12:14   ` Kirill A. Shutemov
2014-10-30 12:14     ` Kirill A. Shutemov
2014-10-29 16:35 ` [PATCH 2/5] mm: gup: add __get_user_pages_unlocked to customize gup_flags Andrea Arcangeli
2014-10-29 16:35   ` Andrea Arcangeli
2014-10-30 12:17   ` Kirill A. Shutemov
2014-10-30 12:17     ` Kirill A. Shutemov
2014-10-30 17:43     ` Andrea Arcangeli [this message]
2014-10-30 17:43       ` Andrea Arcangeli
2014-10-31 16:58       ` Peter Zijlstra
2014-10-31 16:58         ` Peter Zijlstra
2014-10-31 19:15   ` Peter Feiner
2014-10-31 19:15     ` Peter Feiner
2014-10-29 16:35 ` [PATCH 3/5] mm: gup: use get_user_pages_unlocked within get_user_pages_fast Andrea Arcangeli
2014-10-29 16:35   ` Andrea Arcangeli
2014-10-30 12:21   ` Kirill A. Shutemov
2014-10-30 12:21     ` Kirill A. Shutemov
2014-10-31 19:13   ` Peter Feiner
2014-10-31 19:13     ` Peter Feiner
2014-10-29 16:35 ` [PATCH 4/5] mm: gup: use get_user_pages_unlocked Andrea Arcangeli
2014-10-29 16:35   ` Andrea Arcangeli
2014-10-30 12:28   ` Kirill A. Shutemov
2014-10-30 12:28     ` Kirill A. Shutemov
2014-10-31 19:06   ` Peter Feiner
2014-10-31 19:06     ` Peter Feiner
2014-10-29 16:35 ` [PATCH 5/5] mm: gup: kvm " Andrea Arcangeli
2014-10-29 16:35   ` Andrea Arcangeli
2014-10-29 17:14   ` Andres Lagar-Cavilla
2014-10-29 17:14     ` Andres Lagar-Cavilla
2014-10-31 19:16   ` Peter Feiner
2014-10-31 19:16     ` Peter Feiner
  -- strict thread matches above, loose matches on Subject: below --
2015-01-13 16:37 [PATCH 0/5] leverage FAULT_FOLL_ALLOW_RETRY in get_user_pages try#2 Andrea Arcangeli
2015-01-13 16:37 ` [PATCH 2/5] mm: gup: add __get_user_pages_unlocked to customize gup_flags Andrea Arcangeli
2015-01-13 16:37   ` Andrea Arcangeli
2015-01-16 12:51   ` Kirill A. Shutemov
2015-01-16 12:51     ` Kirill A. Shutemov

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