From 3d6035f136009f9cae380022754cba31f32570c5 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 21 Jan 2022 22:14:38 -0800 Subject: [PATCH 01/12] frontswap: remove frontswap_writethrough frontswap_writethrough is never called, so remove it. Link: https://lkml.kernel.org/r/20211224062246.1258487-3-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Juergen Gross Cc: Dan Streetman Cc: Geert Uytterhoeven Cc: Hugh Dickins Cc: Konrad Rzeszutek Wilk Cc: Matthew Wilcox (Oracle) Cc: Seth Jennings Cc: Vitaly Wool Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/vm/frontswap.rst | 6 ------ include/linux/frontswap.h | 1 - mm/frontswap.c | 23 +---------------------- 3 files changed, 1 insertion(+), 29 deletions(-) diff --git a/Documentation/vm/frontswap.rst b/Documentation/vm/frontswap.rst index e2e5ab3e375e..2ab660651d04 100644 --- a/Documentation/vm/frontswap.rst +++ b/Documentation/vm/frontswap.rst @@ -39,12 +39,6 @@ a disk write and, if the data is later read back, a disk read are avoided. If a store returns failure, transcendent memory has rejected the data, and the page can be written to swap as usual. -If a backend chooses, frontswap can be configured as a "writethrough -cache" by calling frontswap_writethrough(). In this mode, the reduction -in swap device writes is lost (and also a non-trivial performance advantage) -in order to allow the backend to arbitrarily "reclaim" space used to -store frontswap pages to more completely manage its memory usage. - Note that if a page is stored and the page already exists in transcendent memory (a "duplicate" store), either the store succeeds and the data is overwritten, or the store fails AND the page is invalidated. This ensures stale data may diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h index b07d88c92bb2..4a03fda41572 100644 --- a/include/linux/frontswap.h +++ b/include/linux/frontswap.h @@ -26,7 +26,6 @@ struct frontswap_ops { extern void frontswap_register_ops(struct frontswap_ops *ops); extern void frontswap_shrink(unsigned long); extern unsigned long frontswap_curr_pages(void); -extern void frontswap_writethrough(bool); #define FRONTSWAP_HAS_EXCLUSIVE_GETS extern void frontswap_tmem_exclusive_gets(bool); diff --git a/mm/frontswap.c b/mm/frontswap.c index 6bed12260dea..51a662a83955 100644 --- a/mm/frontswap.c +++ b/mm/frontswap.c @@ -32,16 +32,6 @@ static struct frontswap_ops *frontswap_ops __read_mostly; #define for_each_frontswap_ops(ops) \ for ((ops) = frontswap_ops; (ops); (ops) = (ops)->next) -/* - * If enabled, frontswap_store will return failure even on success. As - * a result, the swap subsystem will always write the page to swap, in - * effect converting frontswap into a writethrough cache. In this mode, - * there is no direct reduction in swap writes, but a frontswap backend - * can unilaterally "reclaim" any pages in use with no data loss, thus - * providing increases control over maximum memory usage due to frontswap. - */ -static bool frontswap_writethrough_enabled __read_mostly; - /* * If enabled, the underlying tmem implementation is capable of doing * exclusive gets, so frontswap_load, on a successful tmem_get must @@ -170,15 +160,6 @@ void frontswap_register_ops(struct frontswap_ops *ops) } EXPORT_SYMBOL(frontswap_register_ops); -/* - * Enable/disable frontswap writethrough (see above). - */ -void frontswap_writethrough(bool enable) -{ - frontswap_writethrough_enabled = enable; -} -EXPORT_SYMBOL(frontswap_writethrough); - /* * Enable/disable frontswap exclusive gets (see above). */ @@ -283,9 +264,7 @@ int __frontswap_store(struct page *page) } else { inc_frontswap_failed_stores(); } - if (frontswap_writethrough_enabled) - /* report failure so swap also writes to swap device */ - ret = -1; + return ret; } EXPORT_SYMBOL(__frontswap_store); From 71024cb4a0bfe7767aec7a128d0a1a13a37b7fcd Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 21 Jan 2022 22:14:41 -0800 Subject: [PATCH 02/12] frontswap: remove frontswap_tmem_exclusive_gets frontswap_tmem_exclusive_gets is never called, so remove it. Link: https://lkml.kernel.org/r/20211224062246.1258487-4-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Juergen Gross Cc: Dan Streetman Cc: Geert Uytterhoeven Cc: Hugh Dickins Cc: Konrad Rzeszutek Wilk Cc: Matthew Wilcox (Oracle) Cc: Seth Jennings Cc: Vitaly Wool Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/frontswap.h | 2 -- mm/frontswap.c | 23 +---------------------- 2 files changed, 1 insertion(+), 24 deletions(-) diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h index 4a03fda41572..83a56392cc7f 100644 --- a/include/linux/frontswap.h +++ b/include/linux/frontswap.h @@ -26,8 +26,6 @@ struct frontswap_ops { extern void frontswap_register_ops(struct frontswap_ops *ops); extern void frontswap_shrink(unsigned long); extern unsigned long frontswap_curr_pages(void); -#define FRONTSWAP_HAS_EXCLUSIVE_GETS -extern void frontswap_tmem_exclusive_gets(bool); extern bool __frontswap_test(struct swap_info_struct *, pgoff_t); extern void __frontswap_init(unsigned type, unsigned long *map); diff --git a/mm/frontswap.c b/mm/frontswap.c index 51a662a83955..dba7f087ee86 100644 --- a/mm/frontswap.c +++ b/mm/frontswap.c @@ -32,13 +32,6 @@ static struct frontswap_ops *frontswap_ops __read_mostly; #define for_each_frontswap_ops(ops) \ for ((ops) = frontswap_ops; (ops); (ops) = (ops)->next) -/* - * If enabled, the underlying tmem implementation is capable of doing - * exclusive gets, so frontswap_load, on a successful tmem_get must - * mark the page as no longer in frontswap AND mark it dirty. - */ -static bool frontswap_tmem_exclusive_gets_enabled __read_mostly; - #ifdef CONFIG_DEBUG_FS /* * Counters available via /sys/kernel/debug/frontswap (if debugfs is @@ -160,15 +153,6 @@ void frontswap_register_ops(struct frontswap_ops *ops) } EXPORT_SYMBOL(frontswap_register_ops); -/* - * Enable/disable frontswap exclusive gets (see above). - */ -void frontswap_tmem_exclusive_gets(bool enable) -{ - frontswap_tmem_exclusive_gets_enabled = enable; -} -EXPORT_SYMBOL(frontswap_tmem_exclusive_gets); - /* * Called when a swap device is swapon'd. */ @@ -296,13 +280,8 @@ int __frontswap_load(struct page *page) if (!ret) /* successful load */ break; } - if (ret == 0) { + if (ret == 0) inc_frontswap_loads(); - if (frontswap_tmem_exclusive_gets_enabled) { - SetPageDirty(page); - __frontswap_clear(sis, offset); - } - } return ret; } EXPORT_SYMBOL(__frontswap_load); From 0b364446d734da76e421dbfb09e5268270cefaf0 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 21 Jan 2022 22:14:44 -0800 Subject: [PATCH 03/12] frontswap: remove frontswap_shrink frontswap_shrink is never called, so remove it. Link: https://lkml.kernel.org/r/20211224062246.1258487-5-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Juergen Gross Cc: Dan Streetman Cc: Geert Uytterhoeven Cc: Hugh Dickins Cc: Konrad Rzeszutek Wilk Cc: Matthew Wilcox (Oracle) Cc: Seth Jennings Cc: Vitaly Wool Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/vm/frontswap.rst | 13 ------ include/linux/frontswap.h | 1 - mm/frontswap.c | 83 ---------------------------------- 3 files changed, 97 deletions(-) diff --git a/Documentation/vm/frontswap.rst b/Documentation/vm/frontswap.rst index 2ab660651d04..feecc5e24477 100644 --- a/Documentation/vm/frontswap.rst +++ b/Documentation/vm/frontswap.rst @@ -255,19 +255,6 @@ the old data and ensure that it is no longer accessible. Since the swap subsystem then writes the new data to the read swap device, this is the correct course of action to ensure coherency. -* What is frontswap_shrink for? - -When the (non-frontswap) swap subsystem swaps out a page to a real -swap device, that page is only taking up low-value pre-allocated disk -space. But if frontswap has placed a page in transcendent memory, that -page may be taking up valuable real estate. The frontswap_shrink -routine allows code outside of the swap subsystem to force pages out -of the memory managed by frontswap and back into kernel-addressable memory. -For example, in RAMster, a "suction driver" thread will attempt -to "repatriate" pages sent to a remote machine back to the local machine; -this is driven using the frontswap_shrink mechanism when memory pressure -subsides. - * Why does the frontswap patch create the new include file swapfile.h? The frontswap code depends on some swap-subsystem-internal data diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h index 83a56392cc7f..d268d7bb6513 100644 --- a/include/linux/frontswap.h +++ b/include/linux/frontswap.h @@ -24,7 +24,6 @@ struct frontswap_ops { }; extern void frontswap_register_ops(struct frontswap_ops *ops); -extern void frontswap_shrink(unsigned long); extern unsigned long frontswap_curr_pages(void); extern bool __frontswap_test(struct swap_info_struct *, pgoff_t); diff --git a/mm/frontswap.c b/mm/frontswap.c index dba7f087ee86..a77ebba6101b 100644 --- a/mm/frontswap.c +++ b/mm/frontswap.c @@ -341,89 +341,6 @@ static unsigned long __frontswap_curr_pages(void) 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; - - assert_spin_locked(&swap_lock); - plist_for_each_entry(si, &swap_active_head, list) { - si_frontswap_pages = atomic_read(&si->frontswap_pages); - if (total_pages_to_unuse < si_frontswap_pages) { - pages = pages_to_unuse = total_pages_to_unuse; - } 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)) { - ret = -ENOMEM; - continue; - } - vm_unacct_memory(pages); - *unused = pages_to_unuse; - *swapid = si->type; - ret = 0; - break; - } - - return ret; -} - -/* - * Used to check if it's necessary and feasible to unuse pages. - * Return 1 when nothing to do, 0 when need to shrink pages, - * error code when there is an error. - */ -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 1; - } - 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_active_head each time - */ - spin_lock(&swap_lock); - ret = __frontswap_shrink(target_pages, &pages_to_unuse, &type); - spin_unlock(&swap_lock); - if (ret == 0) - try_to_unuse(type, true, pages_to_unuse); - return; -} -EXPORT_SYMBOL(frontswap_shrink); - /* * Count and return the number of frontswap pages across all * swap devices. This is exported so that backend drivers can From 3e8e1af63d7a831f576477c25d9b89049bd2d53d Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 21 Jan 2022 22:14:47 -0800 Subject: [PATCH 04/12] frontswap: remove frontswap_curr_pages frontswap_curr_pages is never called, so remove it. Link: https://lkml.kernel.org/r/20211224062246.1258487-6-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Juergen Gross Cc: Dan Streetman Cc: Geert Uytterhoeven Cc: Hugh Dickins Cc: Konrad Rzeszutek Wilk Cc: Matthew Wilcox (Oracle) Cc: Seth Jennings Cc: Vitaly Wool Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/frontswap.h | 1 - mm/frontswap.c | 28 ---------------------------- 2 files changed, 29 deletions(-) diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h index d268d7bb6513..5205c2977b20 100644 --- a/include/linux/frontswap.h +++ b/include/linux/frontswap.h @@ -24,7 +24,6 @@ struct frontswap_ops { }; extern void frontswap_register_ops(struct frontswap_ops *ops); -extern unsigned long frontswap_curr_pages(void); extern bool __frontswap_test(struct swap_info_struct *, pgoff_t); extern void __frontswap_init(unsigned type, unsigned long *map); diff --git a/mm/frontswap.c b/mm/frontswap.c index a77ebba6101b..af8f68d0e5cc 100644 --- a/mm/frontswap.c +++ b/mm/frontswap.c @@ -330,34 +330,6 @@ void __frontswap_invalidate_area(unsigned type) } EXPORT_SYMBOL(__frontswap_invalidate_area); -static unsigned long __frontswap_curr_pages(void) -{ - unsigned long totalpages = 0; - struct swap_info_struct *si = NULL; - - assert_spin_locked(&swap_lock); - plist_for_each_entry(si, &swap_active_head, list) - totalpages += atomic_read(&si->frontswap_pages); - return totalpages; -} - -/* - * Count and return the number of frontswap pages across all - * swap devices. This is exported so that backend drivers can - * determine current usage without reading debugfs. - */ -unsigned long frontswap_curr_pages(void) -{ - unsigned long totalpages = 0; - - spin_lock(&swap_lock); - totalpages = __frontswap_curr_pages(); - spin_unlock(&swap_lock); - - return totalpages; -} -EXPORT_SYMBOL(frontswap_curr_pages); - static int __init init_frontswap(void) { #ifdef CONFIG_DEBUG_FS From 1cf53c894d15dd4b73397a56fa055d76d3db66b4 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 21 Jan 2022 22:14:51 -0800 Subject: [PATCH 05/12] frontswap: simplify frontswap_init Just use IS_ENABLED() and remove the __frontswap_init indirection. Also remove the unused export. Link: https://lkml.kernel.org/r/20211224062246.1258487-7-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Juergen Gross Cc: Dan Streetman Cc: Geert Uytterhoeven Cc: Hugh Dickins Cc: Konrad Rzeszutek Wilk Cc: Matthew Wilcox (Oracle) Cc: Seth Jennings Cc: Vitaly Wool Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/frontswap.h | 9 +-------- mm/frontswap.c | 3 +-- mm/swapfile.c | 3 ++- 3 files changed, 4 insertions(+), 11 deletions(-) diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h index 5205c2977b20..73d7beb44f2b 100644 --- a/include/linux/frontswap.h +++ b/include/linux/frontswap.h @@ -26,7 +26,7 @@ struct frontswap_ops { extern void frontswap_register_ops(struct frontswap_ops *ops); extern bool __frontswap_test(struct swap_info_struct *, pgoff_t); -extern void __frontswap_init(unsigned type, unsigned long *map); +extern void frontswap_init(unsigned type, unsigned long *map); extern int __frontswap_store(struct page *page); extern int __frontswap_load(struct page *page); extern void __frontswap_invalidate_page(unsigned, pgoff_t); @@ -107,11 +107,4 @@ static inline void frontswap_invalidate_area(unsigned type) __frontswap_invalidate_area(type); } -static inline void frontswap_init(unsigned type, unsigned long *map) -{ -#ifdef CONFIG_FRONTSWAP - __frontswap_init(type, map); -#endif -} - #endif /* _LINUX_FRONTSWAP_H */ diff --git a/mm/frontswap.c b/mm/frontswap.c index af8f68d0e5cc..132d6ad6d70b 100644 --- a/mm/frontswap.c +++ b/mm/frontswap.c @@ -156,7 +156,7 @@ EXPORT_SYMBOL(frontswap_register_ops); /* * Called when a swap device is swapon'd. */ -void __frontswap_init(unsigned type, unsigned long *map) +void frontswap_init(unsigned type, unsigned long *map) { struct swap_info_struct *sis = swap_info[type]; struct frontswap_ops *ops; @@ -179,7 +179,6 @@ void __frontswap_init(unsigned type, unsigned long *map) for_each_frontswap_ops(ops) ops->init(type); } -EXPORT_SYMBOL(__frontswap_init); bool __frontswap_test(struct swap_info_struct *sis, pgoff_t offset) diff --git a/mm/swapfile.c b/mm/swapfile.c index caa9f81a0d15..df5930ccd93d 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2463,7 +2463,8 @@ static void enable_swap_info(struct swap_info_struct *p, int prio, struct swap_cluster_info *cluster_info, unsigned long *frontswap_map) { - frontswap_init(p->type, frontswap_map); + if (IS_ENABLED(CONFIG_FRONTSWAP)) + frontswap_init(p->type, frontswap_map); spin_lock(&swap_lock); spin_lock(&p->lock); setup_swap_info(p, prio, swap_map, cluster_info); From 360be5daa33fe74fc472195242ae2a2337c4320b Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 21 Jan 2022 22:14:54 -0800 Subject: [PATCH 06/12] frontswap: remove the frontswap exports None of the frontswap API is called from modular code. Link: https://lkml.kernel.org/r/20211224062246.1258487-8-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Juergen Gross Cc: Dan Streetman Cc: Geert Uytterhoeven Cc: Hugh Dickins Cc: Konrad Rzeszutek Wilk Cc: Matthew Wilcox (Oracle) Cc: Seth Jennings Cc: Vitaly Wool Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/frontswap.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/mm/frontswap.c b/mm/frontswap.c index 132d6ad6d70b..42d554da53bb 100644 --- a/mm/frontswap.c +++ b/mm/frontswap.c @@ -151,7 +151,6 @@ void frontswap_register_ops(struct frontswap_ops *ops) } } } -EXPORT_SYMBOL(frontswap_register_ops); /* * Called when a swap device is swapon'd. @@ -187,7 +186,6 @@ bool __frontswap_test(struct swap_info_struct *sis, return test_bit(offset, sis->frontswap_map); return false; } -EXPORT_SYMBOL(__frontswap_test); static inline void __frontswap_set(struct swap_info_struct *sis, pgoff_t offset) @@ -250,7 +248,6 @@ int __frontswap_store(struct page *page) return ret; } -EXPORT_SYMBOL(__frontswap_store); /* * "Get" data from frontswap associated with swaptype and offset that were @@ -283,7 +280,6 @@ int __frontswap_load(struct page *page) inc_frontswap_loads(); return ret; } -EXPORT_SYMBOL(__frontswap_load); /* * Invalidate any data from frontswap associated with the specified swaptype @@ -305,7 +301,6 @@ void __frontswap_invalidate_page(unsigned type, pgoff_t offset) __frontswap_clear(sis, offset); inc_frontswap_invalidates(); } -EXPORT_SYMBOL(__frontswap_invalidate_page); /* * Invalidate all data from frontswap associated with all offsets for the @@ -327,7 +322,6 @@ void __frontswap_invalidate_area(unsigned type) atomic_set(&sis->frontswap_pages, 0); bitmap_zero(sis->frontswap_map, sis->max); } -EXPORT_SYMBOL(__frontswap_invalidate_area); static int __init init_frontswap(void) { From 10a9c496789fe2098bfc018650fc77b23ba08a54 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 21 Jan 2022 22:14:57 -0800 Subject: [PATCH 07/12] mm: simplify try_to_unuse Remove the unused frontswap and pages_to_unuse arguments, and mark the function static now that the caller in frontswap is gone. [akpm@linux-foundation.org: fix shmem_unuse() stub, per Matthew] Link: https://lkml.kernel.org/r/20211224062246.1258487-9-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Juergen Gross Cc: Dan Streetman Cc: Geert Uytterhoeven Cc: Hugh Dickins Cc: Konrad Rzeszutek Wilk Cc: Matthew Wilcox (Oracle) Cc: Seth Jennings Cc: Vitaly Wool Cc: Naresh Kamboju Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/frontswap.h | 7 ---- include/linux/shmem_fs.h | 3 +- include/linux/swapfile.h | 1 - mm/shmem.c | 33 +++------------- mm/swapfile.c | 83 +++++++++++---------------------------- 5 files changed, 30 insertions(+), 97 deletions(-) diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h index 73d7beb44f2b..a9817d4fa74c 100644 --- a/include/linux/frontswap.h +++ b/include/linux/frontswap.h @@ -7,13 +7,6 @@ #include #include -/* - * Return code to denote that requested number of - * frontswap pages are unused(moved to page cache). - * Used in shmem_unuse and try_to_unuse. - */ -#define FRONTSWAP_PAGES_UNUSED 2 - struct frontswap_ops { void (*init)(unsigned); /* this swap type was just swapon'ed */ int (*store)(unsigned, pgoff_t, struct page *); /* store a page */ diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index 166158b6e917..e65b80ed09e7 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -83,8 +83,7 @@ extern void shmem_unlock_mapping(struct address_space *mapping); extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, pgoff_t index, gfp_t gfp_mask); extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end); -extern int shmem_unuse(unsigned int type, bool frontswap, - unsigned long *fs_pages_to_unuse); +int shmem_unuse(unsigned int type); extern bool shmem_is_huge(struct vm_area_struct *vma, struct inode *inode, pgoff_t index); diff --git a/include/linux/swapfile.h b/include/linux/swapfile.h index e06febf62978..809cd01ef2c5 100644 --- a/include/linux/swapfile.h +++ b/include/linux/swapfile.h @@ -9,7 +9,6 @@ extern spinlock_t swap_lock; extern struct plist_head swap_active_head; extern struct swap_info_struct *swap_info[]; -extern int try_to_unuse(unsigned int, bool, unsigned long); extern unsigned long generic_max_swapfile_size(void); extern unsigned long max_swapfile_size(void); diff --git a/mm/shmem.c b/mm/shmem.c index 66909efd0a1b..a09b29ec2b45 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -36,7 +36,6 @@ #include #include #include -#include #include #include @@ -1152,7 +1151,7 @@ static void shmem_evict_inode(struct inode *inode) static int shmem_find_swap_entries(struct address_space *mapping, pgoff_t start, unsigned int nr_entries, struct page **entries, pgoff_t *indices, - unsigned int type, bool frontswap) + unsigned int type) { XA_STATE(xas, &mapping->i_pages, start); struct page *page; @@ -1173,9 +1172,6 @@ static int shmem_find_swap_entries(struct address_space *mapping, entry = radix_to_swp_entry(page); if (swp_type(entry) != type) continue; - if (frontswap && - !frontswap_test(swap_info[type], swp_offset(entry))) - continue; indices[ret] = xas.xa_index; entries[ret] = page; @@ -1228,26 +1224,20 @@ static int shmem_unuse_swap_entries(struct inode *inode, struct pagevec pvec, /* * If swap found in inode, free it and move page from swapcache to filecache. */ -static int shmem_unuse_inode(struct inode *inode, unsigned int type, - bool frontswap, unsigned long *fs_pages_to_unuse) +static int shmem_unuse_inode(struct inode *inode, unsigned int type) { struct address_space *mapping = inode->i_mapping; pgoff_t start = 0; struct pagevec pvec; pgoff_t indices[PAGEVEC_SIZE]; - bool frontswap_partial = (frontswap && *fs_pages_to_unuse > 0); int ret = 0; pagevec_init(&pvec); do { unsigned int nr_entries = PAGEVEC_SIZE; - if (frontswap_partial && *fs_pages_to_unuse < PAGEVEC_SIZE) - nr_entries = *fs_pages_to_unuse; - pvec.nr = shmem_find_swap_entries(mapping, start, nr_entries, - pvec.pages, indices, - type, frontswap); + pvec.pages, indices, type); if (pvec.nr == 0) { ret = 0; break; @@ -1257,14 +1247,6 @@ static int shmem_unuse_inode(struct inode *inode, unsigned int type, if (ret < 0) break; - if (frontswap_partial) { - *fs_pages_to_unuse -= ret; - if (*fs_pages_to_unuse == 0) { - ret = FRONTSWAP_PAGES_UNUSED; - break; - } - } - start = indices[pvec.nr - 1]; } while (true); @@ -1276,8 +1258,7 @@ static int shmem_unuse_inode(struct inode *inode, unsigned int type, * device 'type' back into memory, so the swap device can be * unused. */ -int shmem_unuse(unsigned int type, bool frontswap, - unsigned long *fs_pages_to_unuse) +int shmem_unuse(unsigned int type) { struct shmem_inode_info *info, *next; int error = 0; @@ -1300,8 +1281,7 @@ int shmem_unuse(unsigned int type, bool frontswap, atomic_inc(&info->stop_eviction); mutex_unlock(&shmem_swaplist_mutex); - error = shmem_unuse_inode(&info->vfs_inode, type, frontswap, - fs_pages_to_unuse); + error = shmem_unuse_inode(&info->vfs_inode, type); cond_resched(); mutex_lock(&shmem_swaplist_mutex); @@ -4015,8 +3995,7 @@ int __init shmem_init(void) return 0; } -int shmem_unuse(unsigned int type, bool frontswap, - unsigned long *fs_pages_to_unuse) +int shmem_unuse(unsigned int type) { return 0; } diff --git a/mm/swapfile.c b/mm/swapfile.c index df5930ccd93d..82342c77791b 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1923,8 +1923,7 @@ out: static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, unsigned long end, - unsigned int type, bool frontswap, - unsigned long *fs_pages_to_unuse) + unsigned int type) { struct page *page; swp_entry_t entry; @@ -1945,9 +1944,6 @@ static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, continue; offset = swp_offset(entry); - if (frontswap && !frontswap_test(si, offset)) - continue; - pte_unmap(pte); swap_map = &si->swap_map[offset]; page = lookup_swap_cache(entry, vma, addr); @@ -1979,11 +1975,6 @@ static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, try_to_free_swap(page); unlock_page(page); put_page(page); - - if (*fs_pages_to_unuse && !--(*fs_pages_to_unuse)) { - ret = FRONTSWAP_PAGES_UNUSED; - goto out; - } try_next: pte = pte_offset_map(pmd, addr); } while (pte++, addr += PAGE_SIZE, addr != end); @@ -1996,8 +1987,7 @@ out: static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, unsigned long addr, unsigned long end, - unsigned int type, bool frontswap, - unsigned long *fs_pages_to_unuse) + unsigned int type) { pmd_t *pmd; unsigned long next; @@ -2009,8 +1999,7 @@ static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, next = pmd_addr_end(addr, end); if (pmd_none_or_trans_huge_or_clear_bad(pmd)) continue; - ret = unuse_pte_range(vma, pmd, addr, next, type, - frontswap, fs_pages_to_unuse); + ret = unuse_pte_range(vma, pmd, addr, next, type); if (ret) return ret; } while (pmd++, addr = next, addr != end); @@ -2019,8 +2008,7 @@ static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, static inline int unuse_pud_range(struct vm_area_struct *vma, p4d_t *p4d, unsigned long addr, unsigned long end, - unsigned int type, bool frontswap, - unsigned long *fs_pages_to_unuse) + unsigned int type) { pud_t *pud; unsigned long next; @@ -2031,8 +2019,7 @@ static inline int unuse_pud_range(struct vm_area_struct *vma, p4d_t *p4d, next = pud_addr_end(addr, end); if (pud_none_or_clear_bad(pud)) continue; - ret = unuse_pmd_range(vma, pud, addr, next, type, - frontswap, fs_pages_to_unuse); + ret = unuse_pmd_range(vma, pud, addr, next, type); if (ret) return ret; } while (pud++, addr = next, addr != end); @@ -2041,8 +2028,7 @@ static inline int unuse_pud_range(struct vm_area_struct *vma, p4d_t *p4d, static inline int unuse_p4d_range(struct vm_area_struct *vma, pgd_t *pgd, unsigned long addr, unsigned long end, - unsigned int type, bool frontswap, - unsigned long *fs_pages_to_unuse) + unsigned int type) { p4d_t *p4d; unsigned long next; @@ -2053,16 +2039,14 @@ static inline int unuse_p4d_range(struct vm_area_struct *vma, pgd_t *pgd, next = p4d_addr_end(addr, end); if (p4d_none_or_clear_bad(p4d)) continue; - ret = unuse_pud_range(vma, p4d, addr, next, type, - frontswap, fs_pages_to_unuse); + ret = unuse_pud_range(vma, p4d, addr, next, type); if (ret) return ret; } while (p4d++, addr = next, addr != end); return 0; } -static int unuse_vma(struct vm_area_struct *vma, unsigned int type, - bool frontswap, unsigned long *fs_pages_to_unuse) +static int unuse_vma(struct vm_area_struct *vma, unsigned int type) { pgd_t *pgd; unsigned long addr, end, next; @@ -2076,16 +2060,14 @@ static int unuse_vma(struct vm_area_struct *vma, unsigned int type, next = pgd_addr_end(addr, end); if (pgd_none_or_clear_bad(pgd)) continue; - ret = unuse_p4d_range(vma, pgd, addr, next, type, - frontswap, fs_pages_to_unuse); + ret = unuse_p4d_range(vma, pgd, addr, next, type); if (ret) return ret; } while (pgd++, addr = next, addr != end); return 0; } -static int unuse_mm(struct mm_struct *mm, unsigned int type, - bool frontswap, unsigned long *fs_pages_to_unuse) +static int unuse_mm(struct mm_struct *mm, unsigned int type) { struct vm_area_struct *vma; int ret = 0; @@ -2093,8 +2075,7 @@ static int unuse_mm(struct mm_struct *mm, unsigned int type, mmap_read_lock(mm); for (vma = mm->mmap; vma; vma = vma->vm_next) { if (vma->anon_vma) { - ret = unuse_vma(vma, type, frontswap, - fs_pages_to_unuse); + ret = unuse_vma(vma, type); if (ret) break; } @@ -2110,7 +2091,7 @@ static int unuse_mm(struct mm_struct *mm, unsigned int type, * if there are no inuse entries after prev till end of the map. */ static unsigned int find_next_to_unuse(struct swap_info_struct *si, - unsigned int prev, bool frontswap) + unsigned int prev) { unsigned int i; unsigned char count; @@ -2124,8 +2105,7 @@ static unsigned int find_next_to_unuse(struct swap_info_struct *si, for (i = prev + 1; i < si->max; i++) { count = READ_ONCE(si->swap_map[i]); if (count && swap_count(count) != SWAP_MAP_BAD) - if (!frontswap || frontswap_test(si, i)) - break; + break; if ((i % LATENCY_LIMIT) == 0) cond_resched(); } @@ -2136,12 +2116,7 @@ static unsigned int find_next_to_unuse(struct swap_info_struct *si, return i; } -/* - * If the boolean frontswap is true, only unuse pages_to_unuse pages; - * pages_to_unuse==0 means all pages; ignored if frontswap is false - */ -int try_to_unuse(unsigned int type, bool frontswap, - unsigned long pages_to_unuse) +static int try_to_unuse(unsigned int type) { struct mm_struct *prev_mm; struct mm_struct *mm; @@ -2155,13 +2130,10 @@ int try_to_unuse(unsigned int type, bool frontswap, if (!READ_ONCE(si->inuse_pages)) return 0; - if (!frontswap) - pages_to_unuse = 0; - retry: - retval = shmem_unuse(type, frontswap, &pages_to_unuse); + retval = shmem_unuse(type); if (retval) - goto out; + return retval; prev_mm = &init_mm; mmget(prev_mm); @@ -2178,11 +2150,10 @@ retry: spin_unlock(&mmlist_lock); mmput(prev_mm); prev_mm = mm; - retval = unuse_mm(mm, type, frontswap, &pages_to_unuse); - + retval = unuse_mm(mm, type); if (retval) { mmput(prev_mm); - goto out; + return retval; } /* @@ -2199,7 +2170,7 @@ retry: i = 0; while (READ_ONCE(si->inuse_pages) && !signal_pending(current) && - (i = find_next_to_unuse(si, i, frontswap)) != 0) { + (i = find_next_to_unuse(si, i)) != 0) { entry = swp_entry(type, i); page = find_get_page(swap_address_space(entry), i); @@ -2217,14 +2188,6 @@ retry: try_to_free_swap(page); unlock_page(page); put_page(page); - - /* - * For frontswap, we just need to unuse pages_to_unuse, if - * it was specified. Need not check frontswap again here as - * we already zeroed out pages_to_unuse if not frontswap. - */ - if (pages_to_unuse && --pages_to_unuse == 0) - goto out; } /* @@ -2242,10 +2205,10 @@ retry: if (READ_ONCE(si->inuse_pages)) { if (!signal_pending(current)) goto retry; - retval = -EINTR; + return -EINTR; } -out: - return (retval == FRONTSWAP_PAGES_UNUSED) ? 0 : retval; + + return 0; } /* @@ -2577,7 +2540,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) disable_swap_slots_cache_lock(); set_current_oom_origin(); - err = try_to_unuse(p->type, false, 0); /* force unuse all pages */ + err = try_to_unuse(p->type); clear_current_oom_origin(); if (err) { From bd9cd521496ba8d537d8f46f4167bf4221aba9a3 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 21 Jan 2022 22:15:01 -0800 Subject: [PATCH 08/12] frontswap: remove frontswap_test frontswap_test is unused now, remove it. Link: https://lkml.kernel.org/r/20211224062246.1258487-10-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Juergen Gross Cc: Dan Streetman Cc: Geert Uytterhoeven Cc: Hugh Dickins Cc: Konrad Rzeszutek Wilk Cc: Matthew Wilcox (Oracle) Cc: Seth Jennings Cc: Vitaly Wool Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/frontswap.h | 11 ----------- mm/frontswap.c | 2 +- 2 files changed, 1 insertion(+), 12 deletions(-) diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h index a9817d4fa74c..c5b2848d2240 100644 --- a/include/linux/frontswap.h +++ b/include/linux/frontswap.h @@ -18,7 +18,6 @@ struct frontswap_ops { extern void frontswap_register_ops(struct frontswap_ops *ops); -extern bool __frontswap_test(struct swap_info_struct *, pgoff_t); extern void frontswap_init(unsigned type, unsigned long *map); extern int __frontswap_store(struct page *page); extern int __frontswap_load(struct page *page); @@ -33,11 +32,6 @@ static inline bool frontswap_enabled(void) return static_branch_unlikely(&frontswap_enabled_key); } -static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset) -{ - return __frontswap_test(sis, offset); -} - static inline void frontswap_map_set(struct swap_info_struct *p, unsigned long *map) { @@ -56,11 +50,6 @@ static inline bool frontswap_enabled(void) return false; } -static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset) -{ - return false; -} - static inline void frontswap_map_set(struct swap_info_struct *p, unsigned long *map) { diff --git a/mm/frontswap.c b/mm/frontswap.c index 42d554da53bb..f51159f0d75d 100644 --- a/mm/frontswap.c +++ b/mm/frontswap.c @@ -179,7 +179,7 @@ void frontswap_init(unsigned type, unsigned long *map) ops->init(type); } -bool __frontswap_test(struct swap_info_struct *sis, +static bool __frontswap_test(struct swap_info_struct *sis, pgoff_t offset) { if (sis->frontswap_map) From f328c1d16e4c764992895ac9c9425cea861b2ca0 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 21 Jan 2022 22:15:04 -0800 Subject: [PATCH 09/12] frontswap: simplify frontswap_register_ops Given that frontswap_register_ops must be called from built-in code, there is no need to handle the case of swapfiles coming online before or during it, so delete the code that deals with that case. Link: https://lkml.kernel.org/r/20211224062246.1258487-11-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Juergen Gross Cc: Dan Streetman Cc: Geert Uytterhoeven Cc: Hugh Dickins Cc: Konrad Rzeszutek Wilk Cc: Matthew Wilcox (Oracle) Cc: Seth Jennings Cc: Vitaly Wool Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/frontswap.c | 41 ----------------------------------------- 1 file changed, 41 deletions(-) diff --git a/mm/frontswap.c b/mm/frontswap.c index f51159f0d75d..35040fa4eba8 100644 --- a/mm/frontswap.c +++ b/mm/frontswap.c @@ -99,25 +99,6 @@ static inline void inc_frontswap_invalidates(void) { } */ void frontswap_register_ops(struct frontswap_ops *ops) { - DECLARE_BITMAP(a, MAX_SWAPFILES); - DECLARE_BITMAP(b, MAX_SWAPFILES); - struct swap_info_struct *si; - unsigned int i; - - bitmap_zero(a, MAX_SWAPFILES); - bitmap_zero(b, MAX_SWAPFILES); - - spin_lock(&swap_lock); - plist_for_each_entry(si, &swap_active_head, list) { - if (!WARN_ON(!si->frontswap_map)) - __set_bit(si->type, a); - } - spin_unlock(&swap_lock); - - /* the new ops needs to know the currently active swap devices */ - for_each_set_bit(i, a, MAX_SWAPFILES) - ops->init(i); - /* * Setting frontswap_ops must happen after the ops->init() calls * above; cmpxchg implies smp_mb() which will ensure the init is @@ -128,28 +109,6 @@ void frontswap_register_ops(struct frontswap_ops *ops) } while (cmpxchg(&frontswap_ops, ops->next, ops) != ops->next); static_branch_inc(&frontswap_enabled_key); - - spin_lock(&swap_lock); - plist_for_each_entry(si, &swap_active_head, list) { - if (si->frontswap_map) - __set_bit(si->type, b); - } - spin_unlock(&swap_lock); - - /* - * On the very unlikely chance that a swap device was added or - * removed between setting the "a" list bits and the ops init - * calls, we re-check and do init or invalidate for any changed - * bits. - */ - if (unlikely(!bitmap_equal(a, b, MAX_SWAPFILES))) { - for (i = 0; i < MAX_SWAPFILES; i++) { - if (!test_bit(i, a) && test_bit(i, b)) - ops->init(i); - else if (test_bit(i, a) && !test_bit(i, b)) - ops->invalidate_area(i); - } - } } /* From 633423a09cb5cfe61438283e1ce49c23cf4a0611 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 21 Jan 2022 22:15:07 -0800 Subject: [PATCH 10/12] mm: mark swap_lock and swap_active_head static swap_lock and swap_active_head are only used in swapfile.c, so mark them static. Link: https://lkml.kernel.org/r/20211224062246.1258487-12-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Juergen Gross Cc: Dan Streetman Cc: Geert Uytterhoeven Cc: Hugh Dickins Cc: Konrad Rzeszutek Wilk Cc: Matthew Wilcox (Oracle) Cc: Seth Jennings Cc: Vitaly Wool Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/swapfile.h | 2 -- mm/swapfile.c | 4 ++-- 2 files changed, 2 insertions(+), 4 deletions(-) diff --git a/include/linux/swapfile.h b/include/linux/swapfile.h index 809cd01ef2c5..54078542134c 100644 --- a/include/linux/swapfile.h +++ b/include/linux/swapfile.h @@ -6,8 +6,6 @@ * these were static in swapfile.c but frontswap.c needs them and we don't * want to expose them to the dozens of source files that include swap.h */ -extern spinlock_t swap_lock; -extern struct plist_head swap_active_head; extern struct swap_info_struct *swap_info[]; extern unsigned long generic_max_swapfile_size(void); extern unsigned long max_swapfile_size(void); diff --git a/mm/swapfile.c b/mm/swapfile.c index 82342c77791b..bf0df7aa7158 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -49,7 +49,7 @@ static bool swap_count_continued(struct swap_info_struct *, pgoff_t, unsigned char); static void free_swap_count_continuations(struct swap_info_struct *); -DEFINE_SPINLOCK(swap_lock); +static DEFINE_SPINLOCK(swap_lock); static unsigned int nr_swapfiles; atomic_long_t nr_swap_pages; /* @@ -71,7 +71,7 @@ static const char Unused_offset[] = "Unused swap offset entry "; * all active swap_info_structs * protected with swap_lock, and ordered by priority. */ -PLIST_HEAD(swap_active_head); +static PLIST_HEAD(swap_active_head); /* * all available (active, not full) swap_info_structs From 1da0d94a3ec8c5f3793b7be8538b55e60ebeefe3 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 21 Jan 2022 22:15:10 -0800 Subject: [PATCH 11/12] frontswap: remove support for multiple ops There is only a single instance of frontswap ops in the kernel, so simplify the frontswap code by removing support for multiple operations. Link: https://lkml.kernel.org/r/20211224062246.1258487-13-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Juergen Gross Cc: Dan Streetman Cc: Geert Uytterhoeven Cc: Hugh Dickins Cc: Konrad Rzeszutek Wilk Cc: Matthew Wilcox (Oracle) Cc: Seth Jennings Cc: Vitaly Wool Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/frontswap.h | 3 +-- mm/frontswap.c | 50 ++++++++++----------------------------- mm/zswap.c | 8 +++++-- 3 files changed, 19 insertions(+), 42 deletions(-) diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h index c5b2848d2240..a631bac12220 100644 --- a/include/linux/frontswap.h +++ b/include/linux/frontswap.h @@ -13,10 +13,9 @@ struct frontswap_ops { int (*load)(unsigned, pgoff_t, struct page *); /* load a page */ void (*invalidate_page)(unsigned, pgoff_t); /* page no longer needed */ void (*invalidate_area)(unsigned); /* swap type just swapoff'ed */ - struct frontswap_ops *next; /* private pointer to next ops */ }; -extern void frontswap_register_ops(struct frontswap_ops *ops); +int frontswap_register_ops(const struct frontswap_ops *ops); extern void frontswap_init(unsigned type, unsigned long *map); extern int __frontswap_store(struct page *page); diff --git a/mm/frontswap.c b/mm/frontswap.c index 35040fa4eba8..6f69b044a8cc 100644 --- a/mm/frontswap.c +++ b/mm/frontswap.c @@ -27,10 +27,7 @@ DEFINE_STATIC_KEY_FALSE(frontswap_enabled_key); * may be registered, but implementations can never deregister. This * is a simple singly-linked list of all registered implementations. */ -static struct frontswap_ops *frontswap_ops __read_mostly; - -#define for_each_frontswap_ops(ops) \ - for ((ops) = frontswap_ops; (ops); (ops) = (ops)->next) +static const struct frontswap_ops *frontswap_ops __read_mostly; #ifdef CONFIG_DEBUG_FS /* @@ -97,18 +94,14 @@ static inline void inc_frontswap_invalidates(void) { } /* * Register operations for frontswap */ -void frontswap_register_ops(struct frontswap_ops *ops) +int frontswap_register_ops(const struct frontswap_ops *ops) { - /* - * Setting frontswap_ops must happen after the ops->init() calls - * above; cmpxchg implies smp_mb() which will ensure the init is - * complete at this point. - */ - do { - ops->next = frontswap_ops; - } while (cmpxchg(&frontswap_ops, ops->next, ops) != ops->next); + if (frontswap_ops) + return -EINVAL; + frontswap_ops = ops; static_branch_inc(&frontswap_enabled_key); + return 0; } /* @@ -117,7 +110,6 @@ void frontswap_register_ops(struct frontswap_ops *ops) void frontswap_init(unsigned type, unsigned long *map) { struct swap_info_struct *sis = swap_info[type]; - struct frontswap_ops *ops; VM_BUG_ON(sis == NULL); @@ -133,9 +125,7 @@ void frontswap_init(unsigned type, unsigned long *map) * p->frontswap set to something valid to work properly. */ frontswap_map_set(sis, map); - - for_each_frontswap_ops(ops) - ops->init(type); + frontswap_ops->init(type); } static bool __frontswap_test(struct swap_info_struct *sis, @@ -174,7 +164,6 @@ int __frontswap_store(struct page *page) int type = swp_type(entry); struct swap_info_struct *sis = swap_info[type]; pgoff_t offset = swp_offset(entry); - struct frontswap_ops *ops; VM_BUG_ON(!frontswap_ops); VM_BUG_ON(!PageLocked(page)); @@ -188,16 +177,10 @@ int __frontswap_store(struct page *page) */ if (__frontswap_test(sis, offset)) { __frontswap_clear(sis, offset); - for_each_frontswap_ops(ops) - ops->invalidate_page(type, offset); + frontswap_ops->invalidate_page(type, offset); } - /* Try to store in each implementation, until one succeeds. */ - for_each_frontswap_ops(ops) { - ret = ops->store(type, offset, page); - if (!ret) /* successful store */ - break; - } + ret = frontswap_ops->store(type, offset, page); if (ret == 0) { __frontswap_set(sis, offset); inc_frontswap_succ_stores(); @@ -220,7 +203,6 @@ int __frontswap_load(struct page *page) int type = swp_type(entry); struct swap_info_struct *sis = swap_info[type]; pgoff_t offset = swp_offset(entry); - struct frontswap_ops *ops; VM_BUG_ON(!frontswap_ops); VM_BUG_ON(!PageLocked(page)); @@ -230,11 +212,7 @@ int __frontswap_load(struct page *page) return -1; /* Try loading from each implementation, until one succeeds. */ - for_each_frontswap_ops(ops) { - ret = ops->load(type, offset, page); - if (!ret) /* successful load */ - break; - } + ret = frontswap_ops->load(type, offset, page); if (ret == 0) inc_frontswap_loads(); return ret; @@ -247,7 +225,6 @@ int __frontswap_load(struct page *page) void __frontswap_invalidate_page(unsigned type, pgoff_t offset) { struct swap_info_struct *sis = swap_info[type]; - struct frontswap_ops *ops; VM_BUG_ON(!frontswap_ops); VM_BUG_ON(sis == NULL); @@ -255,8 +232,7 @@ void __frontswap_invalidate_page(unsigned type, pgoff_t offset) if (!__frontswap_test(sis, offset)) return; - for_each_frontswap_ops(ops) - ops->invalidate_page(type, offset); + frontswap_ops->invalidate_page(type, offset); __frontswap_clear(sis, offset); inc_frontswap_invalidates(); } @@ -268,7 +244,6 @@ void __frontswap_invalidate_page(unsigned type, pgoff_t offset) void __frontswap_invalidate_area(unsigned type) { struct swap_info_struct *sis = swap_info[type]; - struct frontswap_ops *ops; VM_BUG_ON(!frontswap_ops); VM_BUG_ON(sis == NULL); @@ -276,8 +251,7 @@ void __frontswap_invalidate_area(unsigned type) if (sis->frontswap_map == NULL) return; - for_each_frontswap_ops(ops) - ops->invalidate_area(type); + frontswap_ops->invalidate_area(type); atomic_set(&sis->frontswap_pages, 0); bitmap_zero(sis->frontswap_map, sis->max); } diff --git a/mm/zswap.c b/mm/zswap.c index 7944e3e57e78..cdf6950fcb2e 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -1378,7 +1378,7 @@ static void zswap_frontswap_init(unsigned type) zswap_trees[type] = tree; } -static struct frontswap_ops zswap_frontswap_ops = { +static const struct frontswap_ops zswap_frontswap_ops = { .store = zswap_frontswap_store, .load = zswap_frontswap_load, .invalidate_page = zswap_frontswap_invalidate_page, @@ -1475,11 +1475,15 @@ static int __init init_zswap(void) if (!shrink_wq) goto fallback_fail; - frontswap_register_ops(&zswap_frontswap_ops); + ret = frontswap_register_ops(&zswap_frontswap_ops); + if (ret) + goto destroy_wq; if (zswap_debugfs_init()) pr_warn("debugfs initialization failed\n"); return 0; +destroy_wq: + destroy_workqueue(shrink_wq); fallback_fail: if (pool) zswap_pool_destroy(pool); From 6e61dde82e8bfe65e8ebbe43da45e615bc529236 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 21 Jan 2022 22:15:14 -0800 Subject: [PATCH 12/12] mm: hide the FRONTSWAP Kconfig symbol Select FRONTSWAP from ZSWAP instead of prompting for it. Link: https://lkml.kernel.org/r/20211224062246.1258487-14-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Juergen Gross Cc: Dan Streetman Cc: Geert Uytterhoeven Cc: Hugh Dickins Cc: Konrad Rzeszutek Wilk Cc: Matthew Wilcox (Oracle) Cc: Seth Jennings Cc: Vitaly Wool Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/Kconfig | 18 +++--------------- 1 file changed, 3 insertions(+), 15 deletions(-) diff --git a/mm/Kconfig b/mm/Kconfig index 430240289b02..3326ee3903f3 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -445,20 +445,7 @@ config HAVE_SETUP_PER_CPU_AREA bool config FRONTSWAP - bool "Enable frontswap to cache swap pages if tmem is present" - depends on SWAP - help - Frontswap is so named because it can be thought of as the opposite - of a "backing" store for a swap device. The data is stored into - "transcendent memory", memory that is not directly accessible or - addressable by the kernel and is of unknown and possibly - time-varying size. When space in transcendent memory is available, - a significant swap I/O reduction may be achieved. When none is - available, all frontswap calls are reduced to a single pointer- - compare-against-NULL resulting in a negligible performance hit - and swap data is stored as normal on the matching swap device. - - If unsure, say Y to enable frontswap. + bool config CMA bool "Contiguous Memory Allocator" @@ -523,7 +510,8 @@ config MEM_SOFT_DIRTY config ZSWAP bool "Compressed cache for swap pages (EXPERIMENTAL)" - depends on FRONTSWAP && CRYPTO=y + depends on SWAP && CRYPTO=y + select FRONTSWAP select ZPOOL help A lightweight compressed cache for swap pages. It takes