From: William Lee Irwin III <wli@holomorphy.com>
To: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@digeo.com,
mjbligh@us.ibm.com
Subject: Re: [RFC][PATCH] Fix for latent bug in vmtruncate()
Date: Tue, 13 May 2003 15:06:26 -0700 [thread overview]
Message-ID: <20030513220626.GA29926@holomorphy.com> (raw)
In-Reply-To: <20030513135807.E2929@us.ibm.com>
On Tue, May 13, 2003 at 01:58:07PM -0700, Paul E. McKenney wrote:
> The vmtruncate() function shifts down by PAGE_CACHE_SHIFT, then
> calls vmtruncate_list(), which deals in terms of PAGE_SHIFT
> instead. Currently, no harm done, since PAGE_CACHE_SHIFT and
> PAGE_SHIFT are identical. Some day they might not be, hence
> this patch.
> I also took the liberty of modifying a hand-coded "if" that
> seems to optimize for files that are not mapped to instead
> use unlikely().
pgoff describes a file offset in the same units used to map files
with (the size of an area covered by a PTE), which is PAGE_SIZE (in
mainline; elsewhere it's called MMUPAGE_SIZE and I had to fix this
already for my tree). When they differ this would lose the offset into
the PAGE_CACHE_SIZE-sized file page; hence, well-spotted.
-- wli
WARNING: multiple messages have this Message-ID (diff)
From: William Lee Irwin III <wli@holomorphy.com>
To: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@digeo.com,
mjbligh@us.ibm.com
Subject: Re: [RFC][PATCH] Fix for latent bug in vmtruncate()
Date: Tue, 13 May 2003 15:06:26 -0700 [thread overview]
Message-ID: <20030513220626.GA29926@holomorphy.com> (raw)
In-Reply-To: <20030513135807.E2929@us.ibm.com>
On Tue, May 13, 2003 at 01:58:07PM -0700, Paul E. McKenney wrote:
> The vmtruncate() function shifts down by PAGE_CACHE_SHIFT, then
> calls vmtruncate_list(), which deals in terms of PAGE_SHIFT
> instead. Currently, no harm done, since PAGE_CACHE_SHIFT and
> PAGE_SHIFT are identical. Some day they might not be, hence
> this patch.
> I also took the liberty of modifying a hand-coded "if" that
> seems to optimize for files that are not mapped to instead
> use unlikely().
pgoff describes a file offset in the same units used to map files
with (the size of an area covered by a PTE), which is PAGE_SIZE (in
mainline; elsewhere it's called MMUPAGE_SIZE and I had to fix this
already for my tree). When they differ this would lose the offset into
the PAGE_CACHE_SIZE-sized file page; hence, well-spotted.
-- wli
--
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/ .
Don't email: <a href=mailto:"aart@kvack.org"> aart@kvack.org </a>
next prev parent reply other threads:[~2003-05-13 21:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-13 20:58 [RFC][PATCH] Fix for latent bug in vmtruncate() Paul E. McKenney
2003-05-13 20:58 ` Paul E. McKenney
2003-05-13 22:06 ` William Lee Irwin III [this message]
2003-05-13 22:06 ` William Lee Irwin III
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20030513220626.GA29926@holomorphy.com \
--to=wli@holomorphy.com \
--cc=akpm@digeo.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mjbligh@us.ibm.com \
--cc=paulmck@us.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.