| Message ID | 20200624175244.25837-22-catalin.marinas@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: Memory Tagging Extension user-space support | expand |
On Wed, 24 Jun 2020 18:52:40 +0100 Catalin Marinas <catalin.marinas@arm.com> wrote: > From: Steven Price <steven.price@arm.com> > > Arm's Memory Tagging Extension (MTE) adds some metadata (tags) to > every physical page, when swapping pages out to disk it is necessary to > save these tags, and later restore them when reading the pages back. > > Add some hooks along with dummy implementations to enable the > arch code to handle this. > > Three new hooks are added to the swap code: > * arch_prepare_to_swap() and > * arch_swap_invalidate_page() / arch_swap_invalidate_area(). > One new hook is added to shmem: > * arch_swap_restore_tags() > > ... > > --- a/include/linux/pgtable.h > +++ b/include/linux/pgtable.h > @@ -631,6 +631,29 @@ static inline int arch_unmap_one(struct mm_struct *mm, > } > #endif > > +#ifndef __HAVE_ARCH_PREPARE_TO_SWAP > +static inline int arch_prepare_to_swap(struct page *page) > +{ > + return 0; > +} > +#endif > + > +#ifndef __HAVE_ARCH_SWAP_INVALIDATE > +static inline void arch_swap_invalidate_page(int type, pgoff_t offset) > +{ > +} > + > +static inline void arch_swap_invalidate_area(int type) > +{ > +} > +#endif > + > +#ifndef __HAVE_ARCH_SWAP_RESTORE_TAGS > +static inline void arch_swap_restore_tags(swp_entry_t entry, struct page *page) > +{ > +} > +#endif Presumably these three __HAVE_ARCH_ macros are to be defined in asm/pgtable.h? Acked-by: Andrew Morton <akpm@linux-foundation.org>
On 24/06/2020 19:45, Andrew Morton wrote: > On Wed, 24 Jun 2020 18:52:40 +0100 Catalin Marinas <catalin.marinas@arm.com> wrote: > >> From: Steven Price <steven.price@arm.com> >> >> Arm's Memory Tagging Extension (MTE) adds some metadata (tags) to >> every physical page, when swapping pages out to disk it is necessary to >> save these tags, and later restore them when reading the pages back. >> >> Add some hooks along with dummy implementations to enable the >> arch code to handle this. >> >> Three new hooks are added to the swap code: >> * arch_prepare_to_swap() and >> * arch_swap_invalidate_page() / arch_swap_invalidate_area(). >> One new hook is added to shmem: >> * arch_swap_restore_tags() >> >> ... >> >> --- a/include/linux/pgtable.h >> +++ b/include/linux/pgtable.h >> @@ -631,6 +631,29 @@ static inline int arch_unmap_one(struct mm_struct *mm, >> } >> #endif >> >> +#ifndef __HAVE_ARCH_PREPARE_TO_SWAP >> +static inline int arch_prepare_to_swap(struct page *page) >> +{ >> + return 0; >> +} >> +#endif >> + >> +#ifndef __HAVE_ARCH_SWAP_INVALIDATE >> +static inline void arch_swap_invalidate_page(int type, pgoff_t offset) >> +{ >> +} >> + >> +static inline void arch_swap_invalidate_area(int type) >> +{ >> +} >> +#endif >> + >> +#ifndef __HAVE_ARCH_SWAP_RESTORE_TAGS >> +static inline void arch_swap_restore_tags(swp_entry_t entry, struct page *page) >> +{ >> +} >> +#endif > > Presumably these three __HAVE_ARCH_ macros are to be defined in asm/pgtable.h? That would be the idea (see patch 22). However: Catalin - you've renamed __HAVE_ARCH_SWAP_RESTORE_TAGS in patch 22, but not here! Steve
On Thu, Jun 25, 2020 at 10:04:59AM +0100, Steven Price wrote: > On 24/06/2020 19:45, Andrew Morton wrote: > > On Wed, 24 Jun 2020 18:52:40 +0100 Catalin Marinas <catalin.marinas@arm.com> wrote: > > > > > From: Steven Price <steven.price@arm.com> > > > > > > Arm's Memory Tagging Extension (MTE) adds some metadata (tags) to > > > every physical page, when swapping pages out to disk it is necessary to > > > save these tags, and later restore them when reading the pages back. > > > > > > Add some hooks along with dummy implementations to enable the > > > arch code to handle this. > > > > > > Three new hooks are added to the swap code: > > > * arch_prepare_to_swap() and > > > * arch_swap_invalidate_page() / arch_swap_invalidate_area(). > > > One new hook is added to shmem: > > > * arch_swap_restore_tags() > > > > > > ... > > > > > > --- a/include/linux/pgtable.h > > > +++ b/include/linux/pgtable.h > > > @@ -631,6 +631,29 @@ static inline int arch_unmap_one(struct mm_struct *mm, > > > } > > > #endif > > > +#ifndef __HAVE_ARCH_PREPARE_TO_SWAP > > > +static inline int arch_prepare_to_swap(struct page *page) > > > +{ > > > + return 0; > > > +} > > > +#endif > > > + > > > +#ifndef __HAVE_ARCH_SWAP_INVALIDATE > > > +static inline void arch_swap_invalidate_page(int type, pgoff_t offset) > > > +{ > > > +} > > > + > > > +static inline void arch_swap_invalidate_area(int type) > > > +{ > > > +} > > > +#endif > > > + > > > +#ifndef __HAVE_ARCH_SWAP_RESTORE_TAGS > > > +static inline void arch_swap_restore_tags(swp_entry_t entry, struct page *page) > > > +{ > > > +} > > > +#endif > > > > Presumably these three __HAVE_ARCH_ macros are to be defined in asm/pgtable.h? > > That would be the idea (see patch 22). However: > > Catalin - you've renamed __HAVE_ARCH_SWAP_RESTORE_TAGS in patch 22, but not > here! This was meant to be arch_swap_restore() and __HAVE_ARCH_SWAP_RESTORE (no tags suffix) and it was originally in include/asm-generic/pgtable.h. With Mike's recent reworking getting rid of this file, I messed up the conflict resolution during rebase and re-introduced this file in patch 22. I'll fix it up, it needs to be only in include/linux/pgtable.h.
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 56c1e8eb7bb0..5053d84ece04 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -631,6 +631,29 @@ static inline int arch_unmap_one(struct mm_struct *mm, } #endif +#ifndef __HAVE_ARCH_PREPARE_TO_SWAP +static inline int arch_prepare_to_swap(struct page *page) +{ + return 0; +} +#endif + +#ifndef __HAVE_ARCH_SWAP_INVALIDATE +static inline void arch_swap_invalidate_page(int type, pgoff_t offset) +{ +} + +static inline void arch_swap_invalidate_area(int type) +{ +} +#endif + +#ifndef __HAVE_ARCH_SWAP_RESTORE_TAGS +static inline void arch_swap_restore_tags(swp_entry_t entry, struct page *page) +{ +} +#endif + #ifndef __HAVE_ARCH_PGD_OFFSET_GATE #define pgd_offset_gate(mm, addr) pgd_offset(mm, addr) #endif diff --git a/mm/page_io.c b/mm/page_io.c index e8726f3e3820..9f3835161002 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -252,6 +252,16 @@ int swap_writepage(struct page *page, struct writeback_control *wbc) unlock_page(page); goto out; } + /* + * Arch code may have to preserve more data than just the page + * contents, e.g. memory tags. + */ + ret = arch_prepare_to_swap(page); + if (ret) { + set_page_dirty(page); + unlock_page(page); + goto out; + } if (frontswap_store(page) == 0) { set_page_writeback(page); unlock_page(page); diff --git a/mm/shmem.c b/mm/shmem.c index dacee627dae6..6cf6a1ed3d1c 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1673,6 +1673,12 @@ static int shmem_swapin_page(struct inode *inode, pgoff_t index, } wait_on_page_writeback(page); + /* + * Some architectures may have to restore extra metadata to the + * physical page after reading from swap. + */ + arch_swap_restore_tags(swap, page); + if (shmem_should_replace_page(page, gfp)) { error = shmem_replace_page(&page, gfp, info, index); if (error) diff --git a/mm/swapfile.c b/mm/swapfile.c index 987276c557d1..b7a3ed45e606 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -716,6 +716,7 @@ static void swap_range_free(struct swap_info_struct *si, unsigned long offset, else swap_slot_free_notify = NULL; while (offset <= end) { + arch_swap_invalidate_page(si->type, offset); frontswap_invalidate_page(si->type, offset); if (swap_slot_free_notify) swap_slot_free_notify(si->bdev, offset); @@ -2675,6 +2676,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) frontswap_map = frontswap_map_get(p); spin_unlock(&p->lock); spin_unlock(&swap_lock); + arch_swap_invalidate_area(p->type); frontswap_invalidate_area(p->type); frontswap_map_set(p, NULL); mutex_unlock(&swapon_mutex);