On Wed, 21 Oct 2015, Johannes Weiner wrote: > On Mon, Oct 19, 2015 at 02:13:01PM -0400, Johannes Weiner wrote: > > mm-increase-swap_cluster_max-to-batch-tlb-flushes.patch changed > > SWAP_CLUSTER_MAX from 32 pages to 256 pages, inadvertantly switching > > the scan window for vmpressure detection from 2MB to 16MB. Revert. > > > > Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> > > --- > > mm/vmpressure.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/mm/vmpressure.c b/mm/vmpressure.c > > index c5afd57..74f206b 100644 > > --- a/mm/vmpressure.c > > +++ b/mm/vmpressure.c > > @@ -38,7 +38,7 @@ > > * TODO: Make the window size depend on machine size, as we do for vmstat > > * thresholds. Currently we set it to 512 pages (2MB for 4KB pages). > > */ > > -static const unsigned long vmpressure_win = SWAP_CLUSTER_MAX * 16; > > +static const unsigned long vmpressure_win = SWAP_CLUSTER_MAX; > > Argh, Mel's patch sets SWAP_CLUSTER_MAX to 256, so this should be > SWAP_CLUSTER_MAX * 2 to retain the 512 pages scan window. > > Andrew could you please update this fix in-place? Otherwise I'll > resend a corrected version. > > Thanks, and sorry about that. I don't understand why "SWAP_CLUSTER_MAX * 2" is thought better than "512". Retaining a level of obscurity, that just bit us twice, is a good thing? Hugh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>