From: Andrew Morton <akpm@zip.com.au>
To: William Lee Irwin III <wli@holomorphy.com>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: [patch] adjustments to dirty memory thresholds
Date: Wed, 28 Aug 2002 15:15:28 -0700 [thread overview]
Message-ID: <3D6D4B80.F84F71E4@zip.com.au> (raw)
In-Reply-To: 3D6D477C.F5116BA7@zip.com.au
Andrew Morton wrote:
>
> ...
> Well it's presumably the GFP_NOIO which has killed it - we can't wait
> on PG_writeback pages and we can't write out dirty pages. Taking a
> nap in mempool_alloc is appropriate.
Actually, it might be better to teach mempool_alloc to not call page reclaim
at all if __GFP_FS is not set. Just kick bdflush and go to sleep.
I really, really, really dislike the VM's tendency to go and scan hundreds
of thousands of pages. It's a clear sign of an inappropriate algorithm.
Test something like this, please?
--- 2.5.32/mm/mempool.c~wli Wed Aug 28 15:07:31 2002
+++ 2.5.32-akpm/mm/mempool.c Wed Aug 28 15:12:53 2002
@@ -196,10 +196,11 @@ repeat_alloc:
return element;
/*
- * If the pool is less than 50% full then try harder
- * to allocate an element:
+ * If the pool is less than 50% full and we can perform effective
+ * page reclaim then try harder to allocate an element:
*/
- if ((gfp_mask != gfp_nowait) && (pool->curr_nr <= pool->min_nr/2)) {
+ if ((gfp_mask & __GFP_FS) && (gfp_mask != gfp_nowait) &&
+ (pool->curr_nr <= pool->min_nr/2)) {
element = pool->alloc(gfp_mask, pool->pool_data);
if (likely(element != NULL))
return element;
.
next prev parent reply other threads:[~2002-08-28 22:13 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-08-28 4:39 [patch] adjustments to dirty memory thresholds Andrew Morton
2002-08-28 20:08 ` William Lee Irwin III
2002-08-28 20:27 ` Andrew Morton
2002-08-28 21:42 ` William Lee Irwin III
2002-08-28 21:58 ` Andrew Morton
2002-08-28 22:15 ` Andrew Morton [this message]
2002-08-29 0:26 ` Rik van Riel
2002-08-29 2:10 ` Andrew Morton
2002-08-29 2:10 ` Rik van Riel
2002-08-29 2:52 ` Andrew Morton
2002-09-01 1:37 ` William Lee Irwin III
2002-08-29 3:49 ` William Lee Irwin III
2002-08-29 12:37 ` Rik van Riel
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