Messages in this thread Patch in this message | | | From | Kairui Song <> | Subject | [PATCH 08/24] mm/swap: check readahead policy per entry | Date | Mon, 20 Nov 2023 03:47:24 +0800 |
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From: Kairui Song <kasong@tencent.com>
Currently VMA readahead is globally disabled when any rotate disk is used as swap backend. So multiple swap devices are enabled, if a slower hard disk is set as a low priority fallback, and a high performance SSD is used and high priority swap device, vma readahead is disabled globally. The SSD swap device performance will drop by a lot.
Check readahead policy per entry to avoid such problem.
Signed-off-by: Kairui Song <kasong@tencent.com> --- mm/swap_state.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/mm/swap_state.c b/mm/swap_state.c index ff6756f2e8e4..fb78f7f18ed7 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -321,9 +321,9 @@ static inline bool swap_use_no_readahead(struct swap_info_struct *si, swp_entry_ return data_race(si->flags & SWP_SYNCHRONOUS_IO) && __swap_count(entry) == 1; } -static inline bool swap_use_vma_readahead(void) +static inline bool swap_use_vma_readahead(struct swap_info_struct *si) { - return READ_ONCE(enable_vma_readahead) && !atomic_read(&nr_rotate_swap); + return data_race(si->flags & SWP_SOLIDSTATE) && READ_ONCE(enable_vma_readahead); } /* @@ -341,7 +341,7 @@ struct folio *swap_cache_get_folio(swp_entry_t entry, folio = filemap_get_folio(swap_address_space(entry), swp_offset(entry)); if (!IS_ERR(folio)) { - bool vma_ra = swap_use_vma_readahead(); + bool vma_ra = swap_use_vma_readahead(swp_swap_info(entry)); bool readahead; /* @@ -920,16 +920,18 @@ static struct page *swapin_no_readahead(swp_entry_t entry, gfp_t gfp_mask, struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask, struct vm_fault *vmf, bool *swapcached) { + struct swap_info_struct *si; struct mempolicy *mpol; struct page *page; pgoff_t ilx; bool cached; + si = swp_swap_info(entry); mpol = get_vma_policy(vmf->vma, vmf->address, 0, &ilx); - if (swap_use_no_readahead(swp_swap_info(entry), entry)) { + if (swap_use_no_readahead(si, entry)) { page = swapin_no_readahead(entry, gfp_mask, mpol, ilx, vmf->vma->vm_mm); cached = false; - } else if (swap_use_vma_readahead()) { + } else if (swap_use_vma_readahead(si)) { page = swap_vma_readahead(entry, gfp_mask, mpol, ilx, vmf); cached = true; } else { -- 2.42.0
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