From: Andrea Arcangeli <andrea@suse.de>
To: James Simmons <jsimmons@edgeglobal.com>
Cc: "Stephen C. Tweedie" <sct@redhat.com>, linux-mm@kvack.org
Subject: Re: mm->mmap_sem
Date: Sun, 26 Sep 1999 16:07:17 +0200 (CEST) [thread overview]
Message-ID: <Pine.LNX.4.10.9909261602340.439-100000@laser.random> (raw)
In-Reply-To: <Pine.LNX.4.10.9909252050590.25425-100000@imperial.edgeglobal.com>
On Sat, 25 Sep 1999, James Simmons wrote:
>framebuffer while the accel engine is running. Since many low end cards
>lock if you access the framebuffer and accel engine at the same time.
I see your point.
>Note /dev/fb and /dev/gfx both can be opened by different processes.
If they are two threads and so if they are sharing the same process MM,
you can simply alloc the spinlock in the .data segment (trivial global
variable).
If the two process are not threads (so if they are not sharing the same
MM) then alloc the spinlock (or in general the memory you want to use as
an atomic lock) in a shared shm segment.
>Will this work for mmap regions as well?
Sure: you only need to always acquire the spinlock before accessing the
region of virtual memory. It doesn't metter which kind of memory you are
going to access.
Andrea
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next prev parent reply other threads:[~1999-09-26 14:07 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-09-22 21:02 mm->mmap_sem James Simmons
1999-09-24 0:07 ` mm->mmap_sem Stephen C. Tweedie
1999-09-24 14:59 ` mm->mmap_sem James Simmons
1999-09-24 18:09 ` mm->mmap_sem Stephen C. Tweedie
1999-09-25 1:24 ` mm->mmap_sem James Simmons
1999-09-25 14:55 ` mm->mmap_sem Andrea Arcangeli
1999-09-25 16:50 ` mm->mmap_sem James Simmons
1999-09-25 17:06 ` mm->mmap_sem Andrea Arcangeli
1999-09-26 1:19 ` mm->mmap_sem James Simmons
1999-09-26 14:07 ` Andrea Arcangeli [this message]
1999-09-27 8:55 ` mm->mmap_sem Marcus Sundberg
1999-09-27 19:31 ` mm->mmap_sem James Simmons
1999-09-29 23:00 ` mm->mmap_sem Stephen C. Tweedie
1999-09-30 0:17 ` mm->mmap_sem James Simmons
1999-09-30 0:23 ` mm->mmap_sem Benjamin C.R. LaHaise
1999-09-30 14:59 ` mm->mmap_sem James Simmons
1999-09-30 15:15 ` mm->mmap_sem Benjamin C.R. LaHaise
1999-09-30 16:05 ` mm->mmap_sem James Simmons
1999-09-30 14:54 ` mm->mmap_sem Stephen C. Tweedie
1999-09-27 14:16 ` mm->mmap_sem Stephen C. Tweedie
1999-09-27 20:22 ` mm->mmap_sem James Simmons
1999-09-27 14:13 ` mm->mmap_sem Stephen C. Tweedie
1999-09-27 8:08 ` mm->mmap_sem Neil Conway
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