linux-4.4.1/flush_dcache_page()(arm) の履歴(No.1)

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• linux-4.4.1/flush_dcache_page()(arm) へ行く。
  • 1 (2016-02-23 (火) 13:25:23)

参照元†

• linux-4.4.1/flush_dcache_page()

説明†

• パス: linux-4.4.1/arch/arm/mm/flush.c

• FIXME: これは何？
  • 説明

引数†

• struct page *page
  • linux-4.4.1/page

返り値†

• なし

参考†

実装†

/*
 * Ensure cache coherency between kernel mapping and userspace mapping
 * of this page.
 *
 * We have three cases to consider:
 *  - VIPT non-aliasing cache: fully coherent so nothing required.
 *  - VIVT: fully aliasing, so we need to handle every alias in our
 *          current VM view.
 *  - VIPT aliasing: need to handle one alias in our current VM view.
 *
 * If we need to handle aliasing:
 *  If the page only exists in the page cache and there are no user
 *  space mappings, we can be lazy and remember that we may have dirty
 *  kernel cache lines for later.  Otherwise, we assume we have
 *  aliasing mappings.
 *
 * Note that we disable the lazy flush for SMP configurations where
 * the cache maintenance operations are not automatically broadcasted.
 */
void flush_dcache_page(struct page *page)
{
        struct address_space *mapping;

• • linux-4.4.1/address_space

        /*
         * The zero page is never written to, so never has any dirty
         * cache lines, and therefore never needs to be flushed.
         */
        if (page == ZERO_PAGE(0))
                return;

• • linux-4.4.1/ZERO_PAGE()

        mapping = page_mapping(page);

• • linux-4.4.1/page_mapping()

        if (!cache_ops_need_broadcast() &&
            mapping && !page_mapped(page))
                clear_bit(PG_dcache_clean, &page->flags);

• • linux-4.4.1/cache_ops_need_broadcast()
  • linux-4.4.1/page_mapped()
  • linux-4.4.1/clear_bit()

        else {
                __flush_dcache_page(mapping, page);

• • linux-4.4.1/__flush_dcache_page()

                if (mapping && cache_is_vivt())
                        __flush_dcache_aliases(mapping, page);

• • linux-4.4.1/cache_is_vivt()
  • linux-4.4.1/__flush_dcache_aliases()

                else if (mapping)
                        __flush_icache_all();

• • linux-4.4.1/__flush_icache_all()

                set_bit(PG_dcache_clean, &page->flags);

• • linux-4.4.1/set_bit()

        }
}
EXPORT_SYMBOL(flush_dcache_page);

• • linux-4.4.1/EXPORT_SYMBOL()

コメント†