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author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-07-24 13:15:25 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-07-24 13:15:25 -0700 |
commit | 2b849570264d9f802485e327b7a4b0c52991d26a (patch) | |
tree | 4f2f93a77f614877d4fc4a98a8b100fbe3dcebf0 /mm | |
parent | 62c4d9afa4bcf5315e2745a17a0228bf65b9ba40 (diff) | |
parent | 1d00015e268f9142de0b504b3e4a4905155276f2 (diff) | |
download | linux-2b849570264d9f802485e327b7a4b0c52991d26a.tar.bz2 |
Merge tag 'stable/for-linus-3.6-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/mm
Pull frontswap updates from Konrad Rzeszutek Wilk:
"Cleanups in code and documentation. Little bit of refactoring for
cleaner look."
* tag 'stable/for-linus-3.6-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/mm:
mm/frontswap: cleanup doc and comment error
mm: frontswap: remove unneeded headers
mm: frontswap: split out function to clear a page out
mm: frontswap: remove unnecessary check during initialization
mm: frontswap: make all branches of if statement in put page consistent
mm: frontswap: split frontswap_shrink further to simplify locking
mm: frontswap: split out __frontswap_unuse_pages
mm: frontswap: split out __frontswap_curr_pages
mm: frontswap: trivial coding convention issues
mm: frontswap: remove casting from function calls through ops structure
Diffstat (limited to 'mm')
-rw-r--r-- | mm/frontswap.c | 150 |
1 files changed, 90 insertions, 60 deletions
diff --git a/mm/frontswap.c b/mm/frontswap.c index e25025574a02..6b3e71a2cd48 100644 --- a/mm/frontswap.c +++ b/mm/frontswap.c @@ -11,15 +11,11 @@ * This work is licensed under the terms of the GNU GPL, version 2. */ -#include <linux/mm.h> #include <linux/mman.h> #include <linux/swap.h> #include <linux/swapops.h> -#include <linux/proc_fs.h> #include <linux/security.h> -#include <linux/capability.h> #include <linux/module.h> -#include <linux/uaccess.h> #include <linux/debugfs.h> #include <linux/frontswap.h> #include <linux/swapfile.h> @@ -110,16 +106,21 @@ void __frontswap_init(unsigned type) BUG_ON(sis == NULL); if (sis->frontswap_map == NULL) return; - if (frontswap_enabled) - (*frontswap_ops.init)(type); + frontswap_ops.init(type); } EXPORT_SYMBOL(__frontswap_init); +static inline void __frontswap_clear(struct swap_info_struct *sis, pgoff_t offset) +{ + frontswap_clear(sis, offset); + atomic_dec(&sis->frontswap_pages); +} + /* * "Store" data from a page to frontswap and associate it with the page's * swaptype and offset. Page must be locked and in the swap cache. * If frontswap already contains a page with matching swaptype and - * offset, the frontswap implmentation may either overwrite the data and + * offset, the frontswap implementation may either overwrite the data and * return success or invalidate the page from frontswap and return failure. */ int __frontswap_store(struct page *page) @@ -134,22 +135,21 @@ int __frontswap_store(struct page *page) BUG_ON(sis == NULL); if (frontswap_test(sis, offset)) dup = 1; - ret = (*frontswap_ops.store)(type, offset, page); + ret = frontswap_ops.store(type, offset, page); if (ret == 0) { frontswap_set(sis, offset); inc_frontswap_succ_stores(); if (!dup) atomic_inc(&sis->frontswap_pages); - } else if (dup) { + } else { /* failed dup always results in automatic invalidate of the (older) page from frontswap */ - frontswap_clear(sis, offset); - atomic_dec(&sis->frontswap_pages); - inc_frontswap_failed_stores(); - } else inc_frontswap_failed_stores(); + if (dup) + __frontswap_clear(sis, offset); + } if (frontswap_writethrough_enabled) /* report failure so swap also writes to swap device */ ret = -1; @@ -173,7 +173,7 @@ int __frontswap_load(struct page *page) BUG_ON(!PageLocked(page)); BUG_ON(sis == NULL); if (frontswap_test(sis, offset)) - ret = (*frontswap_ops.load)(type, offset, page); + ret = frontswap_ops.load(type, offset, page); if (ret == 0) inc_frontswap_loads(); return ret; @@ -190,9 +190,8 @@ void __frontswap_invalidate_page(unsigned type, pgoff_t offset) BUG_ON(sis == NULL); if (frontswap_test(sis, offset)) { - (*frontswap_ops.invalidate_page)(type, offset); - atomic_dec(&sis->frontswap_pages); - frontswap_clear(sis, offset); + frontswap_ops.invalidate_page(type, offset); + __frontswap_clear(sis, offset); inc_frontswap_invalidates(); } } @@ -209,67 +208,102 @@ void __frontswap_invalidate_area(unsigned type) BUG_ON(sis == NULL); if (sis->frontswap_map == NULL) return; - (*frontswap_ops.invalidate_area)(type); + frontswap_ops.invalidate_area(type); atomic_set(&sis->frontswap_pages, 0); memset(sis->frontswap_map, 0, sis->max / sizeof(long)); } EXPORT_SYMBOL(__frontswap_invalidate_area); -/* - * Frontswap, like a true swap device, may unnecessarily retain pages - * under certain circumstances; "shrink" frontswap is essentially a - * "partial swapoff" and works by calling try_to_unuse to attempt to - * unuse enough frontswap pages to attempt to -- subject to memory - * constraints -- reduce the number of pages in frontswap to the - * number given in the parameter target_pages. - */ -void frontswap_shrink(unsigned long target_pages) +static unsigned long __frontswap_curr_pages(void) { - struct swap_info_struct *si = NULL; - int si_frontswap_pages; - unsigned long total_pages = 0, total_pages_to_unuse; - unsigned long pages = 0, pages_to_unuse = 0; int type; - bool locked = false; + unsigned long totalpages = 0; + struct swap_info_struct *si = NULL; - /* - * we don't want to hold swap_lock while doing a very - * lengthy try_to_unuse, but swap_list may change - * so restart scan from swap_list.head each time - */ - spin_lock(&swap_lock); - locked = true; - total_pages = 0; + assert_spin_locked(&swap_lock); for (type = swap_list.head; type >= 0; type = si->next) { si = swap_info[type]; - total_pages += atomic_read(&si->frontswap_pages); + totalpages += atomic_read(&si->frontswap_pages); } - if (total_pages <= target_pages) - goto out; - total_pages_to_unuse = total_pages - target_pages; + return totalpages; +} + +static int __frontswap_unuse_pages(unsigned long total, unsigned long *unused, + int *swapid) +{ + int ret = -EINVAL; + struct swap_info_struct *si = NULL; + int si_frontswap_pages; + unsigned long total_pages_to_unuse = total; + unsigned long pages = 0, pages_to_unuse = 0; + int type; + + assert_spin_locked(&swap_lock); for (type = swap_list.head; type >= 0; type = si->next) { si = swap_info[type]; si_frontswap_pages = atomic_read(&si->frontswap_pages); - if (total_pages_to_unuse < si_frontswap_pages) + if (total_pages_to_unuse < si_frontswap_pages) { pages = pages_to_unuse = total_pages_to_unuse; - else { + } else { pages = si_frontswap_pages; pages_to_unuse = 0; /* unuse all */ } /* ensure there is enough RAM to fetch pages from frontswap */ - if (security_vm_enough_memory_mm(current->mm, pages)) + if (security_vm_enough_memory_mm(current->mm, pages)) { + ret = -ENOMEM; continue; + } vm_unacct_memory(pages); + *unused = pages_to_unuse; + *swapid = type; + ret = 0; break; } - if (type < 0) - goto out; - locked = false; + + return ret; +} + +static int __frontswap_shrink(unsigned long target_pages, + unsigned long *pages_to_unuse, + int *type) +{ + unsigned long total_pages = 0, total_pages_to_unuse; + + assert_spin_locked(&swap_lock); + + total_pages = __frontswap_curr_pages(); + if (total_pages <= target_pages) { + /* Nothing to do */ + *pages_to_unuse = 0; + return 0; + } + total_pages_to_unuse = total_pages - target_pages; + return __frontswap_unuse_pages(total_pages_to_unuse, pages_to_unuse, type); +} + +/* + * Frontswap, like a true swap device, may unnecessarily retain pages + * under certain circumstances; "shrink" frontswap is essentially a + * "partial swapoff" and works by calling try_to_unuse to attempt to + * unuse enough frontswap pages to attempt to -- subject to memory + * constraints -- reduce the number of pages in frontswap to the + * number given in the parameter target_pages. + */ +void frontswap_shrink(unsigned long target_pages) +{ + unsigned long pages_to_unuse = 0; + int type, ret; + + /* + * we don't want to hold swap_lock while doing a very + * lengthy try_to_unuse, but swap_list may change + * so restart scan from swap_list.head each time + */ + spin_lock(&swap_lock); + ret = __frontswap_shrink(target_pages, &pages_to_unuse, &type); spin_unlock(&swap_lock); - try_to_unuse(type, true, pages_to_unuse); -out: - if (locked) - spin_unlock(&swap_lock); + if (ret == 0 && pages_to_unuse) + try_to_unuse(type, true, pages_to_unuse); return; } EXPORT_SYMBOL(frontswap_shrink); @@ -281,16 +315,12 @@ EXPORT_SYMBOL(frontswap_shrink); */ unsigned long frontswap_curr_pages(void) { - int type; unsigned long totalpages = 0; - struct swap_info_struct *si = NULL; spin_lock(&swap_lock); - for (type = swap_list.head; type >= 0; type = si->next) { - si = swap_info[type]; - totalpages += atomic_read(&si->frontswap_pages); - } + totalpages = __frontswap_curr_pages(); spin_unlock(&swap_lock); + return totalpages; } EXPORT_SYMBOL(frontswap_curr_pages); |