From mboxrd@z Thu Jan 1 00:00:00 1970 From: Carlos Maiolino Subject: Re: [PATCH v2 2/2] vmscan: take at least one pass with shrinkers Date: Fri, 21 Dec 2012 09:10:13 -0200 Message-ID: <20121221111013.GB8852@andromeda.usersys.redhat.com> References: <1356086810-6950-1-git-send-email-glommer@parallels.com> <1356086810-6950-3-git-send-email-glommer@parallels.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, Dave Shrinnker , Mel Gorman , Johannes Weiner , Michal Hocko , kamezawa.hiroyu@jp.fujitsu.com, "Theodore Ts'o" , Al Viro To: Glauber Costa Return-path: Content-Disposition: inline In-Reply-To: <1356086810-6950-3-git-send-email-glommer@parallels.com> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Fri, Dec 21, 2012 at 02:46:50PM +0400, Glauber Costa wrote: > In very low free kernel memory situations, it may be the case that we > have less objects to free than our initial batch size. If this is the > case, it is better to shrink those, and open space for the new workload > then to keep them and fail the new allocations. > > More specifically, this happens because we encode this in a loop with > the condition: "while (total_scan >= batch_size)". So if we are in such > a case, we'll not even enter the loop. > > This patch modifies turns it into a do () while {} loop, that will > guarantee that we scan it at least once, while keeping the behaviour > exactly the same for the cases in which total_scan > batch_size. > > Signed-off-by: Glauber Costa > Acked-by: Dave Chinner > CC: "Theodore Ts'o" > CC: Al Viro > --- > mm/vmscan.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 7f30961..fcd1aa0 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -280,7 +280,7 @@ unsigned long shrink_slab(struct shrink_control *shrink, > nr_pages_scanned, lru_pages, > max_pass, delta, total_scan); > > - while (total_scan >= batch_size) { > + do { > int nr_before; > > nr_before = do_shrinker_shrink(shrinker, shrink, 0); > @@ -294,7 +294,7 @@ unsigned long shrink_slab(struct shrink_control *shrink, > total_scan -= batch_size; > > cond_resched(); > - } > + } while (total_scan >= batch_size); > > /* > * move the unused scan count back into the shrinker in a > -- > 1.7.11.7 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html Looks Good, Reviewed-by: Carlos Maiolino -- Carlos -- 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: email@kvack.org