Messages in this thread Patch in this message | | | Date | Sun, 26 Jun 2005 18:35:40 -0400 (EDT) | From | Rik Van Riel <> | Subject | [PATCH] 2/2 swap token tuning |
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It turns out that the original swap token implementation, by Song Jiang, only enforced the swap token while the task holding the token is handling a page fault. This patch approximates that, without adding an additional flag to the mm_struct, by checking whether the mm->mmap_sem is held for reading, like the page fault code does.
This patch should have the effect of automatically, and gradually, disabling the enforcement of the swap token when there is little or no paging going on, and "turning up" the intensity of the swap token code the more the task holding the token is thrashing.
Thanks to Song Jiang for pointing out this aspect of the token based thrashing control concept.
Signed-off-by: Rik van Riel
--- 2.6.12-swaptoken/mm/thrash.c.orig 2005-06-17 15:48:29.000000000 -0400 +++ 2.6.12-swaptoken/mm/thrash.c 2005-06-26 17:17:04.000000000 -0400 @@ -19,7 +19,7 @@ static unsigned long swap_token_check; struct mm_struct * swap_token_mm = &init_mm; #define SWAP_TOKEN_CHECK_INTERVAL (HZ * 2) -#define SWAP_TOKEN_TIMEOUT 0 +#define SWAP_TOKEN_TIMEOUT 300 /* * Currently disabled; Needs further code to work at HZ * 300. */ --- 2.6.12-swaptoken/mm/rmap.c.orig 2005-06-26 17:16:50.000000000 -0400 +++ 2.6.12-swaptoken/mm/rmap.c 2005-06-26 17:13:17.000000000 -0400 @@ -301,7 +301,11 @@ static int page_referenced_one(struct pa if (ptep_clear_flush_young(vma, address, pte)) referenced++; - if (mm != current->mm && !ignore_token && has_swap_token(mm)) + /* Pretend the page is referenced if the task has the + swap token and is in the middle of a page fault. */ + if (mm != current->mm && !ignore_token && + has_swap_token(mm) && + sem_is_read_locked(mm->mmap_sem)) referenced++; (*mapcount)--; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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