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The implementation of the lazy MMU mode is currently entirely
arch-specific; core code directly calls arch helpers:
arch_{enter,leave}_lazy_mmu_mode().
We are about to introduce support for nested lazy MMU sections. As things
stand we'd have to duplicate that logic in every arch implementing
lazy_mmu - adding to a fair amount of logic already duplicated across
lazy_mmu implementations.
This patch therefore introduces a new generic layer that calls the
existing arch_* helpers. Two pair of calls are introduced:
* lazy_mmu_mode_enable() ... lazy_mmu_mode_disable()
This is the standard case where the mode is enabled for a given
block of code by surrounding it with enable() and disable()
calls.
* lazy_mmu_mode_pause() ... lazy_mmu_mode_resume()
This is for situations where the mode is temporarily disabled
by first calling pause() and then resume() (e.g. to prevent any
batching from occurring in a critical section).
The documentation in <linux/pgtable.h> will be updated in a subsequent
patch.
No functional change should be introduced at this stage. The
implementation of enable()/resume() and disable()/pause() is currently
identical, but nesting support will change that.
Most of the call sites have been updated using the following Coccinelle
script:
@@
@@
{
...
- arch_enter_lazy_mmu_mode();
+ lazy_mmu_mode_enable();
...
- arch_leave_lazy_mmu_mode();
+ lazy_mmu_mode_disable();
...
}
@@
@@
{
...
- arch_leave_lazy_mmu_mode();
+ lazy_mmu_mode_pause();
...
- arch_enter_lazy_mmu_mode();
+ lazy_mmu_mode_resume();
...
}
A couple of notes regarding x86:
* Xen is currently the only case where explicit handling is required
for lazy MMU when context-switching. This is purely an
implementation detail and using the generic lazy_mmu_mode_*
functions would cause trouble when nesting support is introduced,
because the generic functions must be called from the current task.
For that reason we still use arch_leave() and arch_enter() there.
* x86 calls arch_flush_lazy_mmu_mode() unconditionally in a few
places, but only defines it if PARAVIRT_XXL is selected, and we
are removing the fallback in <linux/pgtable.h>. Add a new fallback
definition to <asm/pgtable.h> to keep things building.
Link: https://lkml.kernel.org/r/20251215150323.2218608-8-kevin.brodsky@arm.com
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David Hildenbrand (Red Hat) <david@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Juegren Gross <jgross@suse.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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| adfs | ||
| affs | ||
| afs | ||
| autofs | ||
| befs | ||
| bfs | ||
| btrfs | ||
| cachefiles | ||
| ceph | ||
| coda | ||
| configfs | ||
| cramfs | ||
| crypto | ||
| debugfs | ||
| devpts | ||
| dlm | ||
| ecryptfs | ||
| efivarfs | ||
| efs | ||
| erofs | ||
| exfat | ||
| exportfs | ||
| ext2 | ||
| ext4 | ||
| f2fs | ||
| fat | ||
| freevxfs | ||
| fuse | ||
| gfs2 | ||
| hfs | ||
| hfsplus | ||
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| iomap | ||
| isofs | ||
| jbd2 | ||
| jffs2 | ||
| jfs | ||
| kernfs | ||
| lockd | ||
| minix | ||
| netfs | ||
| nfs | ||
| nfs_common | ||
| nfsd | ||
| nilfs2 | ||
| nls | ||
| notify | ||
| ntfs3 | ||
| ocfs2 | ||
| omfs | ||
| openpromfs | ||
| orangefs | ||
| overlayfs | ||
| proc | ||
| pstore | ||
| qnx4 | ||
| qnx6 | ||
| quota | ||
| ramfs | ||
| resctrl | ||
| romfs | ||
| smb | ||
| squashfs | ||
| sysfs | ||
| tests | ||
| tracefs | ||
| ubifs | ||
| udf | ||
| ufs | ||
| unicode | ||
| vboxsf | ||
| verity | ||
| xfs | ||
| zonefs | ||
| aio.c | ||
| anon_inodes.c | ||
| attr.c | ||
| backing-file.c | ||
| bad_inode.c | ||
| binfmt_elf_fdpic.c | ||
| binfmt_elf.c | ||
| binfmt_flat.c | ||
| binfmt_misc.c | ||
| binfmt_script.c | ||
| bpf_fs_kfuncs.c | ||
| buffer.c | ||
| char_dev.c | ||
| compat_binfmt_elf.c | ||
| coredump.c | ||
| d_path.c | ||
| dax.c | ||
| dcache.c | ||
| direct-io.c | ||
| drop_caches.c | ||
| eventfd.c | ||
| eventpoll.c | ||
| exec.c | ||
| fcntl.c | ||
| fhandle.c | ||
| file_attr.c | ||
| file_table.c | ||
| file.c | ||
| filesystems.c | ||
| fs_context.c | ||
| fs_dirent.c | ||
| fs_parser.c | ||
| fs_pin.c | ||
| fs_struct.c | ||
| fs-writeback.c | ||
| fsopen.c | ||
| init.c | ||
| inode.c | ||
| internal.h | ||
| ioctl.c | ||
| Kconfig | ||
| Kconfig.binfmt | ||
| kernel_read_file.c | ||
| libfs.c | ||
| locks.c | ||
| Makefile | ||
| mbcache.c | ||
| mnt_idmapping.c | ||
| mount.h | ||
| mpage.c | ||
| namei.c | ||
| namespace.c | ||
| nsfs.c | ||
| open.c | ||
| pidfs.c | ||
| pipe.c | ||
| pnode.c | ||
| pnode.h | ||
| posix_acl.c | ||
| proc_namespace.c | ||
| read_write.c | ||
| readdir.c | ||
| remap_range.c | ||
| select.c | ||
| seq_file.c | ||
| signalfd.c | ||
| splice.c | ||
| stack.c | ||
| stat.c | ||
| statfs.c | ||
| super.c | ||
| sync.c | ||
| sysctls.c | ||
| timerfd.c | ||
| userfaultfd.c | ||
| utimes.c | ||
| xattr.c | ||