On 18 May 2007 10:52:57 +0800 Zou Nan hai <[email protected]> wrote:
> On Fri, 2007-05-18 at 03:32, Andrew Morton wrote:
> > On 17 May 2007 10:40:07 +0800
> > Zou Nan hai <[email protected]> wrote:
> >
> > >
> > Please always prefer to use static inline functions rather than macros.
> > They are more readable, they are more likely to have comments attached to
> > them and they provide typechecking.
> >
> > Please prefer to uninline functions by default. One reason for this is
> > that adding inlines to headers increases include complexity. This code is
> > all __init anyway, so the possible few bytes of text will get removed.
> >
> >
> > Try to avoid using the ARCH_HAS_FOO thing. We have two alternatives:
> >
> > a) use __attribute__((weak))
> >
> > b) do:
> >
> > extern void foo(void);
> > #define foo foo
> >
> > then, elsewhere,
> >
> > #ifndef foo
> > #define foo() bar()
> > #endif
> >
> > Both tricks avoid the introduction of two new symbols into the global
> > namespace to solve a single problem.
> On systems with huge amount of physical memory, VFS cache and memory
> memmap may eat all available system memory under 4G, then the system may
> fail to allocate swiotlb bounce buffer.
> There was a fix for this issue in arch/x86_64/mm/numa.c, but that fix
> dose not cover sparsemem model.
> This patch add fix to sparsemem model by first try to allocate memmap
> above 4G.
>
> Signed-off-by: Zou Nan hai <[email protected]>
> Acked-by: Suresh Siddha <[email protected]>
> ---
> arch/x86_64/mm/init.c | 6 ++++++
> mm/sparse.c | 11 +++++++++++
> 2 files changed, 17 insertions(+)
>
> diff -Nraup a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
> --- a/arch/x86_64/mm/init.c 2007-05-19 16:54:46.000000000 +0800
> +++ b/arch/x86_64/mm/init.c 2007-05-19 17:43:47.000000000 +0800
> @@ -761,3 +761,9 @@ int in_gate_area_no_task(unsigned long a
> {
> return (addr >= VSYSCALL_START) && (addr < VSYSCALL_END);
> }
> +
> +void *alloc_bootmem_high_node(pg_data_t *pgdat, unsigned long size)
> +{
> + return __alloc_bootmem_core(pgdat->bdata, size,
> + SMP_CACHE_BYTES, (4UL*1024*1024*1024), 0);
> +}
> diff -Nraup a/mm/sparse.c b/mm/sparse.c
> --- a/mm/sparse.c 2007-05-19 16:54:48.000000000 +0800
> +++ b/mm/sparse.c 2007-05-19 17:44:01.000000000 +0800
> @@ -209,6 +209,12 @@ static int __meminit sparse_init_one_sec
> return 1;
> }
>
> +__attribute__((weak))
> +void *alloc_bootmem_high_node(pg_data_t *pgdat, unsigned long size)
> +{
> + return NULL;
> +}
> +
> static struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
> {
> struct page *map;
> @@ -219,6 +225,11 @@ static struct page __init *sparse_early_
> if (map)
> return map;
>
> + map = alloc_bootmem_high_node(NODE_DATA(nid),
> + sizeof(struct page) * PAGES_PER_SECTION);
> + if (map)
> + return map;
> +
> map = alloc_bootmem_node(NODE_DATA(nid),
> sizeof(struct page) * PAGES_PER_SECTION);
> if (map)
Fair enough. But we should ensure that there's a prototype in a header
file which is included by both definition sites and by all callers. So the
compiler checks that everything is consistent:
--- a/include/linux/bootmem.h~x86_64-allocate-sparsemem-memmap-above-4g-fix
+++ a/include/linux/bootmem.h
@@ -59,6 +59,7 @@ extern void *__alloc_bootmem_core(struct
unsigned long align,
unsigned long goal,
unsigned long limit);
+extern void *alloc_bootmem_high_node(pg_data_t *pgdat, unsigned long size);
#ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
extern void reserve_bootmem(unsigned long addr, unsigned long size);
_
Andi, does this all look OK for 2.6.22 and for 2.6.21?
-
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