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b9c91c4341
Commit 71024cb4a0 ("frontswap: remove frontswap_tmem_exclusive_gets")
removed support for exclusive loads from frontswap as it was not used.
Bring back exclusive loads support to frontswap by adding an "exclusive"
output parameter to frontswap_ops->load.
On the zswap side, add a module parameter to enable/disable exclusive
loads, and a config option to control the boot default value. Refactor
zswap entry invalidation in zswap_frontswap_invalidate_page() into
zswap_invalidate_entry() to reuse it in zswap_frontswap_load() if
exclusive loads are enabled.
With exclusive loads, we avoid having two copies of the same page in
memory (compressed & uncompressed) after faulting it in from zswap. On
the other hand, if the page is to be reclaimed again without being
dirtied, it will be re-compressed. Compression is not usually slow, and a
page that was just faulted in is less likely to be reclaimed again soon.
Link: https://lkml.kernel.org/r/20230607195143.1473802-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Suggested-by: Yu Zhao <yuzhao@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
91 lines
2.2 KiB
C
91 lines
2.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_FRONTSWAP_H
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#define _LINUX_FRONTSWAP_H
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#include <linux/swap.h>
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#include <linux/mm.h>
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#include <linux/bitops.h>
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#include <linux/jump_label.h>
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struct frontswap_ops {
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void (*init)(unsigned); /* this swap type was just swapon'ed */
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int (*store)(unsigned, pgoff_t, struct page *); /* store a page */
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int (*load)(unsigned, pgoff_t, struct page *, bool *); /* load a page */
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void (*invalidate_page)(unsigned, pgoff_t); /* page no longer needed */
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void (*invalidate_area)(unsigned); /* swap type just swapoff'ed */
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};
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int frontswap_register_ops(const struct frontswap_ops *ops);
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extern void frontswap_init(unsigned type, unsigned long *map);
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extern int __frontswap_store(struct page *page);
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extern int __frontswap_load(struct page *page);
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extern void __frontswap_invalidate_page(unsigned, pgoff_t);
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extern void __frontswap_invalidate_area(unsigned);
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#ifdef CONFIG_FRONTSWAP
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extern struct static_key_false frontswap_enabled_key;
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static inline bool frontswap_enabled(void)
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{
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return static_branch_unlikely(&frontswap_enabled_key);
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}
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static inline void frontswap_map_set(struct swap_info_struct *p,
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unsigned long *map)
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{
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p->frontswap_map = map;
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}
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static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
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{
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return p->frontswap_map;
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}
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#else
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/* all inline routines become no-ops and all externs are ignored */
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static inline bool frontswap_enabled(void)
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{
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return false;
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}
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static inline void frontswap_map_set(struct swap_info_struct *p,
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unsigned long *map)
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{
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}
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static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
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{
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return NULL;
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}
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#endif
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static inline int frontswap_store(struct page *page)
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{
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if (frontswap_enabled())
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return __frontswap_store(page);
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return -1;
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}
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static inline int frontswap_load(struct page *page)
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{
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if (frontswap_enabled())
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return __frontswap_load(page);
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return -1;
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}
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static inline void frontswap_invalidate_page(unsigned type, pgoff_t offset)
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{
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if (frontswap_enabled())
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__frontswap_invalidate_page(type, offset);
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}
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static inline void frontswap_invalidate_area(unsigned type)
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{
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if (frontswap_enabled())
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__frontswap_invalidate_area(type);
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}
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#endif /* _LINUX_FRONTSWAP_H */
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