From: "Benjamin C.R. LaHaise" <blah@kvack.org>
To: Erik Corry <erik@arbat.com>
Cc: Kanoj Sarcar <kanoj@google.engr.sgi.com>,
ak-uu@muc.de, linux-mm@kvack.org
Subject: Re: Assumed Failure rates in Various o.s's ?
Date: Fri, 21 May 1999 10:25:42 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.3.95.990521101041.17710A-100000@as200.spellcast.com> (raw)
In-Reply-To: <19990521120725.A581384@daimi.au.dk>
On Fri, 21 May 1999, Erik Corry wrote:
> According to Andi you already fixed this with a read lock that
> prevents mmap and mmunmap from doing anything while the copy
> is running. This makes sense, since if you do it right with a
> readers/writers lock you can keep out mmap without serialising
> copy_to_user or copy_from_user.
I really like the cleanliness of this approach, but it's troublesome:
memory allocations in other threads would then get blocked during large
IOs -- very bad. What if we instead move from the mm level semaphore to a
per vma locking scheme? The mmap semaphore could become a spinlock for
fudging with list of vmas, and mmap/page faults/... could lock the
specific vma. Or would this be too heavy?
-ben
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next prev parent reply other threads:[~1999-05-21 14:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <199905191428.QAA1295681@beryllium.daimi.au.dk>
1999-05-19 17:37 ` Kanoj Sarcar
1999-05-21 10:07 ` Erik Corry
1999-05-21 14:25 ` Benjamin C.R. LaHaise [this message]
1999-05-21 14:54 ` Erik Corry
1999-05-21 16:02 ` Benjamin C.R. LaHaise
1999-05-21 17:06 ` Kanoj Sarcar
1999-05-21 17:23 ` Kanoj Sarcar
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