[PATCH RFC v2 10/27] mm: Call arch_swap_prepare_to_restore() before arch_swap_restore()
From: Alexandru Elisei <hidden>
Date: 2023-11-19 16:58:32
Also in:
kvmarm, linux-arch, linux-arm-kernel, linux-fsdevel, linux-mm, lkml
Subsystem:
memory management, memory management - core, memory management - swap, the rest, tmpfs (shmem filesystem) · Maintainers:
Andrew Morton, David Hildenbrand, Chris Li, Kairui Song, Linus Torvalds, Hugh Dickins
arm64 uses arch_swap_restore() to restore saved tags before the page is swapped in and it's called in atomic context (with the ptl lock held). Introduce arch_swap_prepare_to_restore() that will allow an architecture to perform extra work during swap in and outside of a critical section. Signed-off-by: Alexandru Elisei <redacted> --- include/linux/pgtable.h | 7 +++++++ mm/memory.c | 4 ++++ mm/shmem.c | 9 +++++++++ mm/swapfile.c | 7 +++++++ 4 files changed, 27 insertions(+)
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index b1001ce361ac..ffdb9b6bed6c 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h@@ -938,6 +938,13 @@ static inline void arch_swap_invalidate_area(int type) } #endif +#ifndef __HAVE_ARCH_SWAP_PREPARE_TO_RESTORE +static inline vm_fault_t arch_swap_prepare_to_restore(swp_entry_t entry, struct folio *folio) +{ + return 0; +} +#endif + #ifndef __HAVE_ARCH_SWAP_RESTORE static inline void arch_swap_restore(swp_entry_t entry, struct folio *folio) {
diff --git a/mm/memory.c b/mm/memory.c
index 1f18ed4a5497..e137f7673749 100644
--- a/mm/memory.c
+++ b/mm/memory.c@@ -3957,6 +3957,10 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) folio_throttle_swaprate(folio, GFP_KERNEL); + ret = arch_swap_prepare_to_restore(entry, folio); + if (ret) + goto out_page; + /* * Back out if somebody else already faulted in this pte. */
diff --git a/mm/shmem.c b/mm/shmem.c
index 71ce5fe5c779..0449c03dbdfd 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c@@ -1840,6 +1840,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, struct swap_info_struct *si; struct folio *folio = NULL; swp_entry_t swap; + vm_fault_t ret; int error; VM_BUG_ON(!*foliop || !xa_is_value(*foliop));
@@ -1888,6 +1889,14 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, } folio_wait_writeback(folio); + ret = arch_swap_prepare_to_restore(swap, folio); + if (ret) { + if (fault_type) + *fault_type = ret; + error = -EINVAL; + goto unlock; + } + /* * Some architectures may have to restore extra metadata to the * folio after reading from swap.
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 4bc70f459164..9983dffce47b 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c@@ -1746,6 +1746,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, spinlock_t *ptl; pte_t *pte, new_pte, old_pte; bool hwpoisoned = PageHWPoison(page); + vm_fault_t err; int ret = 1; swapcache = page;
@@ -1779,6 +1780,12 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, goto setpte; } + err = arch_swap_prepare_to_restore(entry, page_folio(page)); + if (err) { + ret = -EINVAL; + goto out; + } + /* * Some architectures may have to restore extra metadata to the page * when reading from swap. This metadata may be indexed by swap entry
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2.42.1