linux-kernel - Re: [PATCH 11/12] mm: per device dirty threshold

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1177005854.2934.6.camel@lappy>
Date:	Thu, 19 Apr 2007 20:04:14 +0200
From:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	Miklos Szeredi <miklos@...redi.hu>
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org, neilb@...e.de, dgc@....com,
	tomoki.sekiyama.qu@...achi.com, nikita@...sterfs.com,
	trond.myklebust@....uio.no, yingchao.zhou@...il.com
Subject: Re: [PATCH 11/12] mm: per device dirty threshold

On Thu, 2007-04-19 at 19:49 +0200, Miklos Szeredi wrote:
> > +static inline unsigned long bdi_stat_delta(void)
> > +{
> > +#ifdef CONFIG_SMP
> > +	return NR_CPUS * FBC_BATCH;
> 
> Shouln't this be multiplied by the number of counters to sum?  I.e. 3
> if dirty and unstable are separate, and 2 if they are not.

Ah, yes, good catch. How about this:

---

Since we're adding 3 stat counters, tripple the per counter delta as
well.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
---
 mm/page-writeback.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6/mm/page-writeback.c
===================================================================
--- linux-2.6.orig/mm/page-writeback.c	2007-04-19 19:59:26.000000000 +0200
+++ linux-2.6/mm/page-writeback.c	2007-04-19 20:00:09.000000000 +0200
@@ -321,7 +321,7 @@ static void balance_dirty_pages(struct a
 			get_dirty_limits(&background_thresh, &dirty_thresh,
 				       &bdi_thresh, bdi);
 
-			if (bdi_thresh < bdi_stat_delta()) {
+			if (bdi_thresh < 3*bdi_stat_delta()) {
 				bdi_nr_reclaimable =
 					bdi_stat_sum(bdi, BDI_DIRTY) +
 					bdi_stat_sum(bdi, BDI_UNSTABLE);


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/