From: Rik van Riel <riel@conectiva.com.br>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH] drop-behind fix for generic_file_write
Date: Wed, 3 Jan 2001 12:57:55 -0200 (BRDT) [thread overview]
Message-ID: <Pine.LNX.4.21.0101031256040.1403-100000@duckman.distro.conectiva> (raw)
Hi Linus, Alan,
the following (trivial) patch fixes drop-behind behaviour
in generic_file_write to only drop fully written pages.
This increases performance in dbench by about 8% (as
measured by Daniel Phillips) and should get rid of the
logfile bottleneck Ingo Molnar found with the drop-behind
call in generic_file_write in TUX tests.
Please apply this (trivial) patch for 2.4.0.
regards,
Rik
--
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Trailer at 11.
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--- linux-2.4.0-prerelease/mm/filemap.c.orig Wed Jan 3 12:52:13 2001
+++ linux-2.4.0-prerelease/mm/filemap.c Wed Jan 3 12:54:05 2001
@@ -2496,7 +2496,7 @@
}
while (count) {
- unsigned long bytes, index, offset;
+ unsigned long bytes, index, offset, partial = 0;
char *kaddr;
/*
@@ -2506,8 +2506,10 @@
offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
index = pos >> PAGE_CACHE_SHIFT;
bytes = PAGE_CACHE_SIZE - offset;
- if (bytes > count)
+ if (bytes > count) {
bytes = count;
+ partial = 1;
+ }
/*
* Bring in the user page that we will copy from _first_.
@@ -2549,9 +2551,17 @@
buf += status;
}
unlock:
- /* Mark it unlocked again and drop the page.. */
+ /*
+ * Mark it unlocked again and release the page.
+ * In order to prevent large (fast) file writes
+ * from causing too much memory pressure we move
+ * completely written pages to the inactive list.
+ * We do, however, try to keep the pages that may
+ * still be written to (ie. partially written pages).
+ */
UnlockPage(page);
- deactivate_page(page);
+ if (!partial)
+ deactivate_page(page);
page_cache_release(page);
if (status < 0)
-
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next reply other threads:[~2001-01-03 15:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-01-03 14:57 Rik van Riel [this message]
2001-01-03 15:21 ` [PATCH] drop-behind fix for generic_file_write Daniel Phillips
2001-01-03 15:21 ` Rik van Riel
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