"Martin J. Bligh" <[EMAIL PROTECTED]> wrote: > > > > It happens here, a bit. My machine goes up to 60% dirty when it should be > > clamping at 40%. > > > > The variable `total_pages' in page-writeback.c (from > > nr_free_pagecache_pages()) is too high. I trace it back to here: > > > > On node 0 totalpages: 1572864 > > DMA zone: 4096 pages, LIFO batch:1 > > Normal zone: 1568768 pages, LIFO batch:31 > > HighMem zone: 0 pages, LIFO batch:1 > > > > This machine only has 4G of memory, so the platform code is overestimating > > the number of pages by 50%. Can you please check your dmesg, see if your > > system is also getting this wrong? > > I think we're repeatedly iterating over the same zones by walking the > zonelists: > > static unsigned int nr_free_zone_pages(int offset) > { > pg_data_t *pgdat; > unsigned int sum = 0; > int i; > > for_each_pgdat(pgdat) { > struct zone *zone; > > for (i = 0; i < MAX_NR_ZONES; i++) { > unsigned long size, high; > > zone = pgdat->node_zones[i]; > size = zone->present_pages; > high = zone->pages_high; > > if (size > high) > sum += size - high; > } > } > }
I don't think so. We're getting the wrong answer out of calculate_zone_totalpages() which is an init-time thing. Maybe nr_free_zone_pages() is supposed to fix that up post-facto somehow, but calculate_zone_totalpages() sure as heck shouldn't be putting 1568768 into my ZONE_NORMAL's ->node_present_pages. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/