Hi, On 1/15/08, KOSAKI Motohiro <[EMAIL PROTECTED]> wrote: > the notification point to happen whenever the VM moves an > anonymous page to the inactive list - this is a pretty good indication > that there are unused anonymous pages present which will be very likely > swapped out soon.
> + /* deal with the case where there is no > + * swap but an anonymous page would be > + * moved to the inactive list. > + */ > + if (!total_swap_pages && reclaim_mapped && > + PageAnon(page)) > + inactivated_anon = 1; As you know I have had some concerns regarding a too early notification in a swapless system. I did a test with a populated page cache in a swapless system: $ cat /bigfile > /dev/null # populate page cache $ cat /proc/meminfo MemTotal: 1037040 kB MemFree: 113976 kB Buffers: 1068 kB Cached: 907552 kB SwapCached: 0 kB Active: 11116 kB Inactive: 903968 kB HighTotal: 130992 kB HighFree: 252 kB LowTotal: 906048 kB LowFree: 113724 kB SwapTotal: 0 kB SwapFree: 0 kB Dirty: 36 kB Writeback: 0 kB AnonPages: 6484 kB Mapped: 1216 kB Slab: 4024 kB SReclaimable: 864 kB SUnreclaim: 3160 kB PageTables: 444 kB NFS_Unstable: 0 kB Bounce: 0 kB CommitLimit: 518520 kB Committed_AS: 18816 kB VmallocTotal: 114680 kB VmallocUsed: 904 kB VmallocChunk: 113672 kB Start to allocate memory, 10 MB every second, exit on notification. $ cat /proc/meminfo # just after notification MemTotal: 1037040 kB MemFree: 123468 kB Buffers: 876 kB Cached: 897976 kB SwapCached: 0 kB Active: 12984 kB Inactive: 892332 kB HighTotal: 130992 kB HighFree: 1064 kB LowTotal: 906048 kB LowFree: 122404 kB SwapTotal: 0 kB SwapFree: 0 kB Dirty: 0 kB Writeback: 0 kB AnonPages: 6484 kB Mapped: 1220 kB Slab: 4012 kB SReclaimable: 864 kB SUnreclaim: 3148 kB PageTables: 448 kB NFS_Unstable: 0 kB Bounce: 0 kB CommitLimit: 518520 kB Committed_AS: 18816 kB VmallocTotal: 114680 kB VmallocUsed: 904 kB VmallocChunk: 113672 kB The notification fires after only ~100 MB allocated, i.e., when page reclaim is beginning to nag from page cache. Isn't this a bit early? Repeating the test with swap enabled results in a notification after ~600 MB allocated, which is more reasonable and just before the system starts to swap. Cheers, Daniel -- 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/
