lkml.org 
[lkml]   [2010]   [Mar]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: [PATCH 05/11] Export unusable free space index via /proc/unusable_index
    On Fri, 12 Mar 2010 16:41:21 +0000
    Mel Gorman <mel@csn.ul.ie> wrote:

    > Unusable free space index is a measure of external fragmentation that
    > takes the allocation size into account. For the most part, the huge page
    > size will be the size of interest but not necessarily so it is exported
    > on a per-order and per-zone basis via /proc/unusable_index.
    >
    > The index is a value between 0 and 1. It can be expressed as a
    > percentage by multiplying by 100 as documented in
    > Documentation/filesystems/proc.txt.
    >
    > Signed-off-by: Mel Gorman <mel@csn.ul.ie>
    > Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
    > Acked-by: Rik van Riel <riel@redhat.com>
    > ---
    > Documentation/filesystems/proc.txt | 13 ++++-
    > mm/vmstat.c | 120 ++++++++++++++++++++++++++++++++++++
    > 2 files changed, 132 insertions(+), 1 deletions(-)
    >
    > diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
    > index 5e132b5..5c4b0fb 100644
    > --- a/Documentation/filesystems/proc.txt
    > +++ b/Documentation/filesystems/proc.txt
    > @@ -452,6 +452,7 @@ Table 1-5: Kernel info in /proc
    > sys See chapter 2
    > sysvipc Info of SysVIPC Resources (msg, sem, shm) (2.4)
    > tty Info of tty drivers
    > + unusable_index Additional page allocator information (see text)(2.5)
    > uptime System uptime
    > version Kernel version
    > video bttv info of video resources (2.4)
    > @@ -609,7 +610,7 @@ ZONE_DMA, 4 chunks of 2^1*PAGE_SIZE in ZONE_DMA, 101 chunks of 2^4*PAGE_SIZE
    > available in ZONE_NORMAL, etc...
    >
    > More information relevant to external fragmentation can be found in
    > -pagetypeinfo.
    > +pagetypeinfo and unusable_index
    >
    > > cat /proc/pagetypeinfo
    > Page block order: 9
    > @@ -650,6 +651,16 @@ unless memory has been mlock()'d. Some of the Reclaimable blocks should
    > also be allocatable although a lot of filesystem metadata may have to be
    > reclaimed to achieve this.
    >
    > +> cat /proc/unusable_index
    > +Node 0, zone DMA 0.000 0.000 0.000 0.001 0.005 0.013 0.021 0.037 0.037 0.101 0.230
    > +Node 0, zone Normal 0.000 0.000 0.000 0.001 0.002 0.002 0.005 0.015 0.028 0.028 0.054
    > +
    > +The unusable free space index measures how much of the available free
    > +memory cannot be used to satisfy an allocation of a given size and is a
    > +value between 0 and 1. The higher the value, the more of free memory is
    > +unusable and by implication, the worse the external fragmentation is. This
    > +can be expressed as a percentage by multiplying by 100.
    > +

    I'm sorry but how this information is different from buddyinfo ?

    Thanks,
    -Kame



    > ..............................................................................
    > meminfo:
    > diff --git a/mm/vmstat.c b/mm/vmstat.c
    > index 7f760cb..ca42e10 100644
    > --- a/mm/vmstat.c
    > +++ b/mm/vmstat.c
    > @@ -453,6 +453,106 @@ static int frag_show(struct seq_file *m, void *arg)
    > return 0;
    > }
    >
    > +
    > +struct contig_page_info {
    > + unsigned long free_pages;
    > + unsigned long free_blocks_total;
    > + unsigned long free_blocks_suitable;
    > +};
    > +
    > +/*
    > + * Calculate the number of free pages in a zone, how many contiguous
    > + * pages are free and how many are large enough to satisfy an allocation of
    > + * the target size. Note that this function makes to attempt to estimate
    > + * how many suitable free blocks there *might* be if MOVABLE pages were
    > + * migrated. Calculating that is possible, but expensive and can be
    > + * figured out from userspace
    > + */
    > +static void fill_contig_page_info(struct zone *zone,
    > + unsigned int suitable_order,
    > + struct contig_page_info *info)
    > +{
    > + unsigned int order;
    > +
    > + info->free_pages = 0;
    > + info->free_blocks_total = 0;
    > + info->free_blocks_suitable = 0;
    > +
    > + for (order = 0; order < MAX_ORDER; order++) {
    > + unsigned long blocks;
    > +
    > + /* Count number of free blocks */
    > + blocks = zone->free_area[order].nr_free;
    > + info->free_blocks_total += blocks;
    > +
    > + /* Count free base pages */
    > + info->free_pages += blocks << order;
    > +
    > + /* Count the suitable free blocks */
    > + if (order >= suitable_order)
    > + info->free_blocks_suitable += blocks <<
    > + (order - suitable_order);
    > + }
    > +}
    > +
    > +/*
    > + * Return an index indicating how much of the available free memory is
    > + * unusable for an allocation of the requested size.
    > + */
    > +static int unusable_free_index(unsigned int order,
    > + struct contig_page_info *info)
    > +{
    > + /* No free memory is interpreted as all free memory is unusable */
    > + if (info->free_pages == 0)
    > + return 1000;
    > +
    > + /*
    > + * Index should be a value between 0 and 1. Return a value to 3
    > + * decimal places.
    > + *
    > + * 0 => no fragmentation
    > + * 1 => high fragmentation
    > + */
    > + return ((info->free_pages - (info->free_blocks_suitable << order)) * 1000) / info->free_pages;
    > +
    > +}
    > +
    > +static void unusable_show_print(struct seq_file *m,
    > + pg_data_t *pgdat, struct zone *zone)
    > +{
    > + unsigned int order;
    > + int index;
    > + struct contig_page_info info;
    > +
    > + seq_printf(m, "Node %d, zone %8s ",
    > + pgdat->node_id,
    > + zone->name);
    > + for (order = 0; order < MAX_ORDER; ++order) {
    > + fill_contig_page_info(zone, order, &info);
    > + index = unusable_free_index(order, &info);
    > + seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
    > + }
    > +
    > + seq_putc(m, '\n');
    > +}
    > +
    > +/*
    > + * Display unusable free space index
    > + * XXX: Could be a lot more efficient, but it's not a critical path
    > + */
    > +static int unusable_show(struct seq_file *m, void *arg)
    > +{
    > + pg_data_t *pgdat = (pg_data_t *)arg;
    > +
    > + /* check memoryless node */
    > + if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
    > + return 0;
    > +
    > + walk_zones_in_node(m, pgdat, unusable_show_print);
    > +
    > + return 0;
    > +}
    > +
    > static void pagetypeinfo_showfree_print(struct seq_file *m,
    > pg_data_t *pgdat, struct zone *zone)
    > {
    > @@ -603,6 +703,25 @@ static const struct file_operations pagetypeinfo_file_ops = {
    > .release = seq_release,
    > };
    >
    > +static const struct seq_operations unusable_op = {
    > + .start = frag_start,
    > + .next = frag_next,
    > + .stop = frag_stop,
    > + .show = unusable_show,
    > +};
    > +
    > +static int unusable_open(struct inode *inode, struct file *file)
    > +{
    > + return seq_open(file, &unusable_op);
    > +}
    > +
    > +static const struct file_operations unusable_file_ops = {
    > + .open = unusable_open,
    > + .read = seq_read,
    > + .llseek = seq_lseek,
    > + .release = seq_release,
    > +};
    > +
    > #ifdef CONFIG_ZONE_DMA
    > #define TEXT_FOR_DMA(xx) xx "_dma",
    > #else
    > @@ -947,6 +1066,7 @@ static int __init setup_vmstat(void)
    > #ifdef CONFIG_PROC_FS
    > proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
    > proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
    > + proc_create("unusable_index", S_IRUGO, NULL, &unusable_file_ops);
    > proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
    > proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
    > #endif
    > --
    > 1.6.5
    >
    > --
    > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    > the body of a message to majordomo@vger.kernel.org
    > More majordomo info at http://vger.kernel.org/majordomo-info.html
    > Please read the FAQ at http://www.tux.org/lkml/
    >



    \
     
     \ /
      Last update: 2010-03-15 06:47    [W:0.037 / U:30.612 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site