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| author | J. Bruce Fields <bfields@citi.umich.edu> | 2009-06-15 18:08:07 -0700 |
|---|---|---|
| committer | J. Bruce Fields <bfields@citi.umich.edu> | 2009-06-15 18:08:07 -0700 |
| commit | 7eef4091a653c243a87e5375c54504cc03bec4d8 (patch) | |
| tree | f65b77f830b2c8f7d014512badfef5df0d591ee9 /mm/page_alloc.c | |
| parent | 0a93a47f042c459f0f46942c3a920e3c81878031 (diff) | |
| parent | 07a2039b8eb0af4ff464efd3dfd95de5c02648c6 (diff) | |
Merge commit 'v2.6.30' into for-2.6.31
Diffstat (limited to 'mm/page_alloc.c')
| -rw-r--r-- | mm/page_alloc.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e2f26991fff1..fe753ecf2aa5 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2681,6 +2681,7 @@ static void __meminit zone_init_free_lists(struct zone *zone) static int zone_batchsize(struct zone *zone) { +#ifdef CONFIG_MMU int batch; /* @@ -2706,9 +2707,26 @@ static int zone_batchsize(struct zone *zone) * of pages of one half of the possible page colors * and the other with pages of the other colors. */ - batch = (1 << (fls(batch + batch/2)-1)) - 1; + batch = rounddown_pow_of_two(batch + batch/2) - 1; return batch; + +#else + /* The deferral and batching of frees should be suppressed under NOMMU + * conditions. + * + * The problem is that NOMMU needs to be able to allocate large chunks + * of contiguous memory as there's no hardware page translation to + * assemble apparent contiguous memory from discontiguous pages. + * + * Queueing large contiguous runs of pages for batching, however, + * causes the pages to actually be freed in smaller chunks. As there + * can be a significant delay between the individual batches being + * recycled, this leads to the once large chunks of space being + * fragmented and becoming unavailable for high-order allocations. + */ + return 0; +#endif } static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch) |