Messages in this thread Patch in this message | | | Date | Sat, 26 Nov 2005 12:43:14 -0500 (EST) | From | Rik van Riel <> | Subject | [PATCH] temporarily disable swap token on memory pressure |
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Some users (hi Zwane) have seen a problem when running a workload that eats nearly all of physical memory - th system does an OOM kill, even when there is still a lot of swap free.
The problem appears to be a very big task that is holding the swap token, and the VM has a very hard time finding any other page in the system that is swappable.
Instead of ignoring the swap token when sc->priority reaches 0, we could simply take the swap token away from the memory hog and make sure we don't give it back to the memory hog for a few seconds.
This patch resolves the problem Zwane ran into.
This patch is against yesterday's git head.
Signed-off-by: Rik van Riel <riel@redhat.com>
Index: linux-2.6-token/mm/thrash.c =================================================================== --- linux-2.6-token.orig/mm/thrash.c +++ linux-2.6-token/mm/thrash.c @@ -57,14 +57,17 @@ void grab_swap_token(void) /* We have the token. Let others know we still need it. */ if (has_swap_token(current->mm)) { current->mm->recent_pagein = 1; + if (unlikely(!swap_token_default_timeout)) + disable_swap_token(); return; } if (time_after(jiffies, swap_token_check)) { - /* Can't get swapout protection if we exceed our RSS limit. */ - // if (current->mm->rss > current->mm->rlimit_rss) - // return; + if (!swap_token_default_timeout) { + swap_token_check = jiffies + SWAP_TOKEN_CHECK_INTERVAL; + return; + } /* ... or if we recently held the token. */ if (time_before(jiffies, current->mm->swap_token_time)) @@ -95,6 +98,7 @@ void __put_swap_token(struct mm_struct * { spin_lock(&swap_token_lock); if (likely(mm == swap_token_mm)) { + mm->swap_token_time = jiffies + SWAP_TOKEN_CHECK_INTERVAL; swap_token_mm = &init_mm; swap_token_check = jiffies; } Index: linux-2.6-token/include/linux/rmap.h =================================================================== --- linux-2.6-token.orig/include/linux/rmap.h +++ linux-2.6-token/include/linux/rmap.h @@ -89,7 +89,7 @@ static inline void page_dup_rmap(struct /* * Called from mm/vmscan.c to handle paging out */ -int page_referenced(struct page *, int is_locked, int ignore_token); +int page_referenced(struct page *, int is_locked); int try_to_unmap(struct page *); /* @@ -109,7 +109,7 @@ unsigned long page_address_in_vma(struct #define anon_vma_prepare(vma) (0) #define anon_vma_link(vma) do {} while (0) -#define page_referenced(page,l,i) TestClearPageReferenced(page) +#define page_referenced(page,l) TestClearPageReferenced(page) #define try_to_unmap(page) SWAP_FAIL #endif /* CONFIG_MMU */ Index: linux-2.6-token/include/linux/swap.h =================================================================== --- linux-2.6-token.orig/include/linux/swap.h +++ linux-2.6-token/include/linux/swap.h @@ -239,6 +239,11 @@ static inline void put_swap_token(struct __put_swap_token(mm); } +static inline void disable_swap_token(void) +{ + put_swap_token(swap_token_mm); +} + #else /* CONFIG_SWAP */ #define total_swap_pages 0 Index: linux-2.6-token/mm/vmscan.c =================================================================== --- linux-2.6-token.orig/mm/vmscan.c +++ linux-2.6-token/mm/vmscan.c @@ -407,7 +407,7 @@ static int shrink_list(struct list_head if (PageWriteback(page)) goto keep_locked; - referenced = page_referenced(page, 1, sc->priority <= 0); + referenced = page_referenced(page, 1); /* In active use or really unfreeable? Activate it. */ if (referenced && page_mapping_inuse(page)) goto activate_locked; @@ -756,7 +756,7 @@ refill_inactive_zone(struct zone *zone, if (page_mapped(page)) { if (!reclaim_mapped || (total_swap_pages == 0 && PageAnon(page)) || - page_referenced(page, 0, sc->priority <= 0)) { + page_referenced(page, 0)) { list_add(&page->lru, &l_active); continue; } @@ -960,6 +960,8 @@ int try_to_free_pages(struct zone **zone sc.nr_reclaimed = 0; sc.priority = priority; sc.swap_cluster_max = SWAP_CLUSTER_MAX; + if (!priority) + disable_swap_token(); shrink_caches(zones, &sc); shrink_slab(sc.nr_scanned, gfp_mask, lru_pages); if (reclaim_state) { @@ -1056,6 +1058,10 @@ loop_again: int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */ unsigned long lru_pages = 0; + /* The swap token gets in the way of swapout... */ + if (!priority) + disable_swap_token(); + all_zones_ok = 1; if (nr_pages == 0) { @@ -1360,6 +1366,7 @@ int zone_reclaim(struct zone *zone, gfp_ sc.nr_reclaimed = 0; /* scan at the highest priority */ sc.priority = 0; + disable_swap_token(); if (nr_pages > SWAP_CLUSTER_MAX) sc.swap_cluster_max = nr_pages; Index: linux-2.6-token/mm/rmap.c =================================================================== --- linux-2.6-token.orig/mm/rmap.c +++ linux-2.6-token/mm/rmap.c @@ -292,7 +292,7 @@ pte_t *page_check_address(struct page *p * repeatedly from either page_referenced_anon or page_referenced_file. */ static int page_referenced_one(struct page *page, - struct vm_area_struct *vma, unsigned int *mapcount, int ignore_token) + struct vm_area_struct *vma, unsigned int *mapcount) { struct mm_struct *mm = vma->vm_mm; unsigned long address; @@ -313,7 +313,7 @@ static int page_referenced_one(struct pa /* 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) && + if (mm != current->mm && has_swap_token(mm) && rwsem_is_locked(&mm->mmap_sem)) referenced++; @@ -323,7 +323,7 @@ out: return referenced; } -static int page_referenced_anon(struct page *page, int ignore_token) +static int page_referenced_anon(struct page *page) { unsigned int mapcount; struct anon_vma *anon_vma; @@ -336,8 +336,7 @@ static int page_referenced_anon(struct p mapcount = page_mapcount(page); list_for_each_entry(vma, &anon_vma->head, anon_vma_node) { - referenced += page_referenced_one(page, vma, &mapcount, - ignore_token); + referenced += page_referenced_one(page, vma, &mapcount); if (!mapcount) break; } @@ -356,7 +355,7 @@ static int page_referenced_anon(struct p * * This function is only called from page_referenced for object-based pages. */ -static int page_referenced_file(struct page *page, int ignore_token) +static int page_referenced_file(struct page *page) { unsigned int mapcount; struct address_space *mapping = page->mapping; @@ -394,8 +393,7 @@ static int page_referenced_file(struct p referenced++; break; } - referenced += page_referenced_one(page, vma, &mapcount, - ignore_token); + referenced += page_referenced_one(page, vma, &mapcount); if (!mapcount) break; } @@ -412,13 +410,10 @@ static int page_referenced_file(struct p * Quick test_and_clear_referenced for all mappings to a page, * returns the number of ptes which referenced the page. */ -int page_referenced(struct page *page, int is_locked, int ignore_token) +int page_referenced(struct page *page, int is_locked) { int referenced = 0; - if (!swap_token_default_timeout) - ignore_token = 1; - if (page_test_and_clear_young(page)) referenced++; @@ -427,15 +422,14 @@ int page_referenced(struct page *page, i if (page_mapped(page) && page->mapping) { if (PageAnon(page)) - referenced += page_referenced_anon(page, ignore_token); + referenced += page_referenced_anon(page); else if (is_locked) - referenced += page_referenced_file(page, ignore_token); + referenced += page_referenced_file(page); else if (TestSetPageLocked(page)) referenced++; else { if (page->mapping) - referenced += page_referenced_file(page, - ignore_token); + referenced += page_referenced_file(page); unlock_page(page); } } - 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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