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    Subject[PATCH -mm 10/14] bootmem: factor out the marking of a PFN range
    Introduce new helpers that mark a range that resides completely on a
    node or node-agnostic ranges that might also span node boundaries.

    The free/reserve API functions will then directly use these helpers.

    Note that the free/reserve semantics become more strict: while the
    prior code took basically arbitrary range arguments and marked the
    PFNs that happen to fall into that range, the new code requires
    node-specific ranges to be completely on the node. The node-agnostic
    requests might span node boundaries as long as the nodes are
    contiguous.

    Passing ranges that do not satisfy these criteria is a bug.

    Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
    CC: Ingo Molnar <mingo@elte.hu>
    CC: Yinghai Lu <yhlu.kernel@gmail.com>
    CC: Andi Kleen <andi@firstfloor.org>
    ---

    Sorry, this diff is still not really readable. Any ideas how to split
    that stuff properly?

    include/linux/bootmem.h | 2
    mm/bootmem.c | 191 ++++++++++++++++++------------------------------
    2 files changed, 73 insertions(+), 120 deletions(-)

    --- a/mm/bootmem.c
    +++ b/mm/bootmem.c
    @@ -228,12 +228,16 @@ unsigned long __init free_all_bootmem(vo
    static void __init __free(bootmem_data_t *bdata,
    unsigned long sidx, unsigned long eidx)
    {
    - unsigned long idx;
    + unsigned long idx, start;

    bdebug("nid=%d start=%lx end=%lx\n", bdata - bootmem_node_data,
    sidx + PFN_DOWN(bdata->node_boot_start),
    eidx + PFN_DOWN(bdata->node_boot_start));

    + start = bdata->node_boot_start + PFN_PHYS(sidx);
    + if (bdata->last_success > start)
    + bdata->last_success = start;
    +
    for (idx = sidx; idx < eidx; idx++)
    if (!test_and_clear_bit(idx, bdata->node_bootmem_map))
    BUG();
    @@ -263,39 +267,57 @@ static int __init __reserve(bootmem_data
    return 0;
    }

    -static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
    - unsigned long size)
    +static int __init mark_bootmem_node(bootmem_data_t *bdata,
    + unsigned long start, unsigned long end,
    + int reserve, int flags)
    {
    unsigned long sidx, eidx;
    - unsigned long i;

    - BUG_ON(!size);
    + bdebug("nid=%d start=%lx end=%lx reserve=%d flags=%x\n",
    + bdata - bootmem_node_data, start, end, reserve, flags);

    - /* out range */
    - if (addr + size < bdata->node_boot_start ||
    - PFN_DOWN(addr) > bdata->node_low_pfn)
    - return;
    - /*
    - * round down end of usable mem, partially free pages are
    - * considered reserved.
    - */
    + BUG_ON(start < PFN_DOWN(bdata->node_boot_start));
    + BUG_ON(end > bdata->node_low_pfn);

    - if (addr >= bdata->node_boot_start && addr < bdata->last_success)
    - bdata->last_success = addr;
    + sidx = start - PFN_DOWN(bdata->node_boot_start);
    + eidx = end - PFN_DOWN(bdata->node_boot_start);

    - /*
    - * Round up to index to the range.
    - */
    - if (PFN_UP(addr) > PFN_DOWN(bdata->node_boot_start))
    - sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start);
    + if (reserve)
    + return __reserve(bdata, sidx, eidx, flags);
    else
    - sidx = 0;
    + __free(bdata, sidx, eidx);
    + return 0;
    +}
    +
    +static int __init mark_bootmem(unsigned long start, unsigned long end,
    + int reserve, int flags)
    +{
    + unsigned long pos;
    + bootmem_data_t *bdata;

    - eidx = PFN_DOWN(addr + size - bdata->node_boot_start);
    - if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
    - eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
    + pos = start;
    + list_for_each_entry(bdata, &bdata_list, list) {
    + int err;
    + unsigned long max;
    +
    + if (pos < PFN_DOWN(bdata->node_boot_start)) {
    + BUG_ON(pos != start);
    + continue;
    + }

    - __free(bdata, sidx, eidx);
    + max = min(bdata->node_low_pfn, end);
    +
    + err = mark_bootmem_node(bdata, pos, max, reserve, flags);
    + if (reserve && err) {
    + mark_bootmem(start, pos, 0, 0);
    + return err;
    + }
    +
    + if (max == end)
    + return 0;
    + pos = bdata->node_low_pfn;
    + }
    + BUG();
    }

    /**
    @@ -306,12 +328,17 @@ static void __init free_bootmem_core(boo
    *
    * Partial pages will be considered reserved and left as they are.
    *
    - * Only physical pages that actually reside on @pgdat are marked.
    + * The range must reside completely on the specified node.
    */
    void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
    unsigned long size)
    {
    - free_bootmem_core(pgdat->bdata, physaddr, size);
    + unsigned long start, end;
    +
    + start = PFN_UP(physaddr);
    + end = PFN_DOWN(physaddr + size);
    +
    + mark_bootmem_node(pgdat->bdata, start, end, 0, 0);
    }

    /**
    @@ -321,83 +348,16 @@ void __init free_bootmem_node(pg_data_t
    *
    * Partial pages will be considered reserved and left as they are.
    *
    - * All physical pages within the range are marked, no matter what
    - * node they reside on.
    + * The range must be contiguous but may span node boundaries.
    */
    void __init free_bootmem(unsigned long addr, unsigned long size)
    {
    - bootmem_data_t *bdata;
    - list_for_each_entry(bdata, &bdata_list, list)
    - free_bootmem_core(bdata, addr, size);
    -}
    -
    -/*
    - * Marks a particular physical memory range as unallocatable. Usable RAM
    - * might be used for boot-time allocations - or it might get added
    - * to the free page pool later on.
    - */
    -static int __init can_reserve_bootmem_core(bootmem_data_t *bdata,
    - unsigned long addr, unsigned long size, int flags)
    -{
    - unsigned long sidx, eidx;
    - unsigned long i;
    -
    - BUG_ON(!size);
    + unsigned long start, end;

    - /* out of range, don't hold other */
    - if (addr + size < bdata->node_boot_start ||
    - PFN_DOWN(addr) > bdata->node_low_pfn)
    - return 0;
    + start = PFN_UP(addr);
    + end = PFN_DOWN(addr + size);

    - /*
    - * Round up to index to the range.
    - */
    - if (addr > bdata->node_boot_start)
    - sidx= PFN_DOWN(addr - bdata->node_boot_start);
    - else
    - sidx = 0;
    -
    - eidx = PFN_UP(addr + size - bdata->node_boot_start);
    - if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
    - eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
    -
    - for (i = sidx; i < eidx; i++) {
    - if (test_bit(i, bdata->node_bootmem_map)) {
    - if (flags & BOOTMEM_EXCLUSIVE)
    - return -EBUSY;
    - }
    - }
    -
    - return 0;
    -
    -}
    -
    -static void __init reserve_bootmem_core(bootmem_data_t *bdata,
    - unsigned long addr, unsigned long size, int flags)
    -{
    - unsigned long sidx, eidx;
    - unsigned long i;
    -
    - BUG_ON(!size);
    -
    - /* out of range */
    - if (addr + size < bdata->node_boot_start ||
    - PFN_DOWN(addr) > bdata->node_low_pfn)
    - return;
    -
    - /*
    - * Round up to index to the range.
    - */
    - if (addr > bdata->node_boot_start)
    - sidx= PFN_DOWN(addr - bdata->node_boot_start);
    - else
    - sidx = 0;
    -
    - eidx = PFN_UP(addr + size - bdata->node_boot_start);
    - if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
    - eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
    -
    - return __reserve(bdata, sidx, eidx, flags);
    + mark_bootmem(start, end, 0, 0);
    }

    /**
    @@ -407,17 +367,17 @@ static void __init reserve_bootmem_core(
    *
    * Partial pages will be reserved.
    *
    - * Only physical pages that actually reside on @pgdat are marked.
    + * The range must reside completely on the specified node.
    */
    -void __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
    +int __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
    unsigned long size, int flags)
    {
    - int ret;
    + unsigned long start, end;

    - ret = can_reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
    - if (ret < 0)
    - return;
    - reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
    + start = PFN_DOWN(physaddr);
    + end = PFN_UP(physaddr + size);
    +
    + return mark_bootmem_node(pgdat->bdata, start, end, 1, flags);
    }

    #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
    @@ -428,24 +388,17 @@ void __init reserve_bootmem_node(pg_data
    *
    * Partial pages will be reserved.
    *
    - * All physical pages within the range are marked, no matter what
    - * node they reside on.
    + * The range must be contiguous but may span node boundaries.
    */
    int __init reserve_bootmem(unsigned long addr, unsigned long size,
    int flags)
    {
    - bootmem_data_t *bdata;
    - int ret;
    + unsigned long start, end;

    - list_for_each_entry(bdata, &bdata_list, list) {
    - ret = can_reserve_bootmem_core(bdata, addr, size, flags);
    - if (ret < 0)
    - return ret;
    - }
    - list_for_each_entry(bdata, &bdata_list, list)
    - reserve_bootmem_core(bdata, addr, size, flags);
    + start = PFN_DOWN(addr);
    + end = PFN_UP(addr + size);

    - return 0;
    + return mark_bootmem(start, end, 1, flags);
    }
    #endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */

    @@ -716,7 +669,7 @@ void * __init alloc_bootmem_section(unsi
    if (start_nr != section_nr || end_nr != section_nr) {
    printk(KERN_WARNING "alloc_bootmem failed on section %ld.\n",
    section_nr);
    - free_bootmem_core(pgdat->bdata, __pa(ptr), size);
    + free_bootmem_node(pgdat, __pa(ptr), size);
    ptr = NULL;
    }

    --- a/include/linux/bootmem.h
    +++ b/include/linux/bootmem.h
    @@ -66,7 +66,7 @@ extern void free_bootmem(unsigned long a
    #define BOOTMEM_DEFAULT 0
    #define BOOTMEM_EXCLUSIVE (1<<0)

    -extern void reserve_bootmem_node(pg_data_t *pgdat,
    +extern int reserve_bootmem_node(pg_data_t *pgdat,
    unsigned long physaddr,
    unsigned long size,
    int flags);
    --



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