The patch titled
Subject: mm: allow per-VMA locks on file-backed VMAs
has been added to the -mm mm-unstable branch. Its filename is
mm-allow-per-vma-locks-on-file-backed-vmas.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-allow-per-vma-locks-on-file-backed-vmas.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: allow per-VMA locks on file-backed VMAs
Date: Mon, 24 Jul 2023 19:54:02 +0100
Remove the TCP layering violation by allowing per-VMA locks on all VMAs.
The fault path will immediately fail in handle_mm_fault(). There may be a
small performance reduction from this patch as a little unnecessary work
will be done on each page fault. See later patches for the improvement.
Link: https://lkml.kernel.org/r/20230724185410.1124082-3-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Arjun Roy <arjunroy@xxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Punit Agrawal <punit.agrawal@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
MAINTAINERS | 1 -
include/linux/net_mm.h | 17 -----------------
include/net/tcp.h | 1 -
mm/memory.c | 12 ++++++------
net/ipv4/tcp.c | 11 ++++-------
5 files changed, 10 insertions(+), 32 deletions(-)
--- a/include/linux/net_mm.h
+++ /dev/null
@@ -1,17 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-#ifdef CONFIG_MMU
-
-#ifdef CONFIG_INET
-extern const struct vm_operations_struct tcp_vm_ops;
-static inline bool vma_is_tcp(const struct vm_area_struct *vma)
-{
- return vma->vm_ops == &tcp_vm_ops;
-}
-#else
-static inline bool vma_is_tcp(const struct vm_area_struct *vma)
-{
- return false;
-}
-#endif /* CONFIG_INET*/
-
-#endif /* CONFIG_MMU */
--- a/include/net/tcp.h~mm-allow-per-vma-locks-on-file-backed-vmas
+++ a/include/net/tcp.h
@@ -45,7 +45,6 @@
#include <linux/memcontrol.h>
#include <linux/bpf-cgroup.h>
#include <linux/siphash.h>
-#include <linux/net_mm.h>
extern struct inet_hashinfo tcp_hashinfo;
--- a/MAINTAINERS~mm-allow-per-vma-locks-on-file-backed-vmas
+++ a/MAINTAINERS
@@ -14809,7 +14809,6 @@ NETWORKING [TCP]
M: Eric Dumazet <edumazet@xxxxxxxxxx>
L: netdev@xxxxxxxxxxxxxxx
S: Maintained
-F: include/linux/net_mm.h
F: include/linux/tcp.h
F: include/net/tcp.h
F: include/trace/events/tcp.h
--- a/mm/memory.c~mm-allow-per-vma-locks-on-file-backed-vmas
+++ a/mm/memory.c
@@ -77,7 +77,6 @@
#include <linux/ptrace.h>
#include <linux/vmalloc.h>
#include <linux/sched/sysctl.h>
-#include <linux/net_mm.h>
#include <trace/events/kmem.h>
@@ -5360,6 +5359,11 @@ vm_fault_t handle_mm_fault(struct vm_are
goto out;
}
+ if ((flags & FAULT_FLAG_VMA_LOCK) && !vma_is_anonymous(vma)) {
+ vma_end_read(vma);
+ return VM_FAULT_RETRY;
+ }
+
/*
* Enable the memcg OOM handling for faults triggered in user
* space. Kernel faults are handled more gracefully.
@@ -5531,12 +5535,8 @@ retry:
if (!vma)
goto inval;
- /* Only anonymous and tcp vmas are supported for now */
- if (!vma_is_anonymous(vma) && !vma_is_tcp(vma))
- goto inval;
-
/* find_mergeable_anon_vma uses adjacent vmas which are not locked */
- if (!vma->anon_vma && !vma_is_tcp(vma))
+ if (vma_is_anonymous(vma) && !vma->anon_vma)
goto inval;
if (!vma_start_read(vma))
--- a/net/ipv4/tcp.c~mm-allow-per-vma-locks-on-file-backed-vmas
+++ a/net/ipv4/tcp.c
@@ -1739,7 +1739,7 @@ void tcp_update_recv_tstamps(struct sk_b
}
#ifdef CONFIG_MMU
-const struct vm_operations_struct tcp_vm_ops = {
+static const struct vm_operations_struct tcp_vm_ops = {
};
int tcp_mmap(struct file *file, struct socket *sock,
@@ -2042,13 +2042,10 @@ static struct vm_area_struct *find_tcp_v
unsigned long address,
bool *mmap_locked)
{
- struct vm_area_struct *vma = NULL;
+ struct vm_area_struct *vma = lock_vma_under_rcu(mm, address);
-#ifdef CONFIG_PER_VMA_LOCK
- vma = lock_vma_under_rcu(mm, address);
-#endif
if (vma) {
- if (!vma_is_tcp(vma)) {
+ if (vma->vm_ops != &tcp_vm_ops) {
vma_end_read(vma);
return NULL;
}
@@ -2058,7 +2055,7 @@ static struct vm_area_struct *find_tcp_v
mmap_read_lock(mm);
vma = vma_lookup(mm, address);
- if (!vma || !vma_is_tcp(vma)) {
+ if (!vma || vma->vm_ops != &tcp_vm_ops) {
mmap_read_unlock(mm);
return NULL;
}
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
rmap-pass-the-folio-to-__page_check_anon_rmap.patch
highmem-add-memcpy_to_folio-and-memcpy_from_folio.patch
affs-convert-affs_symlink_read_folio-to-use-the-folio.patch
affs-convert-data-read-and-write-to-use-folios.patch
migrate-use-folio_set_bh-instead-of-set_bh_page.patch
ntfs3-convert-ntfs_get_block_vbo-to-use-a-folio.patch
jbd2-use-a-folio-in-jbd2_journal_write_metadata_buffer.patch
buffer-remove-set_bh_page.patch
zswap-make-zswap_store-take-a-folio.patch
memcg-convert-get_obj_cgroup_from_page-to-get_obj_cgroup_from_folio.patch
swap-remove-some-calls-to-compound_head-in-swap_readpage.patch
zswap-make-zswap_load-take-a-folio.patch
mm-remove-config_per_vma_lock-ifdefs.patch
mm-allow-per-vma-locks-on-file-backed-vmas.patch
mm-move-fault_flag_vma_lock-check-from-handle_mm_fault.patch
mm-handle-pud-faults-under-the-vma-lock.patch
mm-handle-some-pmd-faults-under-the-vma-lock.patch
mm-move-fault_flag_vma_lock-check-down-in-handle_pte_fault.patch
mm-move-fault_flag_vma_lock-check-down-from-do_fault.patch
mm-run-the-fault-around-code-under-the-vma-lock.patch
mm-handle-swap-and-numa-pte-faults-under-the-vma-lock.patch
mm-handle-faults-that-merely-update-the-accessed-bit-under-the-vma-lock.patch
