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@ -42,25 +42,26 @@ Cambridge, MA 02139, USA. */ |
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#if PAGE_COPY_THRESHOLD |
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#include <assert.h> |
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#define PAGE_COPY_FWD_MAYBE(dstp, srcp, nbytes_left, nbytes) \ |
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do \ |
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{ \ |
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if ((nbytes) >= PAGE_COPY_THRESHOLD && \ |
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PAGE_OFFSET (dstp) == PAGE_OFFSET (srcp)) \ |
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PAGE_OFFSET ((dstp) - (srcp)) == 0) \ |
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{ \ |
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/* The amount to copy is past the threshold for copying \
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pages virtually with kernel VM operations, and the \ |
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source and destination addresses have the same alignment. */ \ |
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size_t nbytes_before = PAGE_OFFSET (PAGE_SIZE - PAGE_OFFSET (dstp));\ |
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size_t nbytes_before = PAGE_OFFSET (-(dstp)); \ |
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if (nbytes_before != 0) \ |
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{ \ |
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/* First copy the words before the first page boundary. */ \ |
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WORD_COPY_FWD (dstp, srcp, nbytes_left, nbytes_before); \ |
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nbytes_before -= nbytes_left; \ |
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assert (nbytes_left == 0); \ |
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nbytes -= nbytes_before; \ |
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} \ |
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if (nbytes_before == 0) \ |
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PAGE_COPY_FWD (dstp, srcp, nbytes_left, nbytes); \ |
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PAGE_COPY_FWD (dstp, srcp, nbytes_left, nbytes); \ |
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} \ |
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} while (0) |
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