From d791ea676b66489ef6dabd04cd655f5c77426e40 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 9 May 2022 18:20:48 -0700 Subject: mm: reclaim mustn't enter FS for SWP_FS_OPS swap-space If swap-out is using filesystem operations (SWP_FS_OPS), then it is not safe to enter the FS for reclaim. So only down-grade the requirement for swap pages to __GFP_IO after checking that SWP_FS_OPS are not being used. This makes the calculation of "may_enter_fs" slightly more complex, so move it into a separate function. with that done, there is little value in maintaining the bool variable any more. So replace the may_enter_fs variable with a may_enter_fs() function. This removes any risk for the variable becoming out-of-date. Link: https://lkml.kernel.org/r/164859778124.29473.16176717935781721855.stgit@noble.brown Signed-off-by: NeilBrown Reviewed-by: Christoph Hellwig Tested-by: David Howells Tested-by: Geert Uytterhoeven Cc: Hugh Dickins Cc: Mel Gorman Cc: Trond Myklebust Cc: Miaohe Lin Signed-off-by: Andrew Morton --- mm/swap.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'mm/swap.h') diff --git a/mm/swap.h b/mm/swap.h index f8265bf0ce00..e19f185df5e2 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -50,6 +50,10 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag, struct page *swapin_readahead(swp_entry_t entry, gfp_t flag, struct vm_fault *vmf); +static inline unsigned int page_swap_flags(struct page *page) +{ + return page_swap_info(page)->flags; +} #else /* CONFIG_SWAP */ static inline int swap_readpage(struct page *page, bool do_poll) { @@ -129,5 +133,9 @@ static inline void clear_shadow_from_swap_cache(int type, unsigned long begin, { } +static inline unsigned int page_swap_flags(struct page *page) +{ + return 0; +} #endif /* CONFIG_SWAP */ #endif /* _MM_SWAP_H */ -- cgit v1.2.3