| Message ID | 9b54eef0b41b678cc5f318bd5ae0917bba5b8e21.1674538665.git-series.apopple@nvidia.com (mailing list archive) |
|---|---|
| State | RFC |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [RFC,01/19] mm: Introduce vm_account | expand |
On Tue, Jan 24, 2023 at 04:42:39PM +1100, Alistair Popple wrote: > diff --git a/include/net/sock.h b/include/net/sock.h > index dcd72e6..bc3a868 100644 > --- a/include/net/sock.h > +++ b/include/net/sock.h > @@ -334,6 +334,7 @@ struct sk_filter; > * @sk_security: used by security modules > * @sk_mark: generic packet mark > * @sk_cgrp_data: cgroup data for this cgroup > + * @sk_vm_account: data for pinned memory accounting > * @sk_memcg: this socket's memory cgroup association > * @sk_write_pending: a write to stream socket waits to start > * @sk_state_change: callback to indicate change in the state of the sock > @@ -523,6 +524,7 @@ struct sock { > void *sk_security; > #endif > struct sock_cgroup_data sk_cgrp_data; > + struct vm_account sk_vm_account; > struct mem_cgroup *sk_memcg; > void (*sk_state_change)(struct sock *sk); > void (*sk_data_ready)(struct sock *sk); I'm not sure this makes sense in a sock - each sock can be shared with different proceses.. > diff --git a/net/rds/message.c b/net/rds/message.c > index b47e4f0..2138a70 100644 > --- a/net/rds/message.c > +++ b/net/rds/message.c > @@ -99,7 +99,7 @@ static void rds_rm_zerocopy_callback(struct rds_sock *rs, > struct list_head *head; > unsigned long flags; > > - mm_unaccount_pinned_pages(&znotif->z_mmp); > + mm_unaccount_pinned_pages(&rs->rs_sk.sk_vm_account, &znotif->z_mmp); > q = &rs->rs_zcookie_queue; > spin_lock_irqsave(&q->lock, flags); > head = &q->zcookie_head; > @@ -367,6 +367,7 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter * > int ret = 0; > int length = iov_iter_count(from); > struct rds_msg_zcopy_info *info; > + struct vm_account *vm_account = &rm->m_rs->rs_sk.sk_vm_account; > > rm->m_inc.i_hdr.h_len = cpu_to_be32(iov_iter_count(from)); > > @@ -380,7 +381,9 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter * > return -ENOMEM; > INIT_LIST_HEAD(&info->rs_zcookie_next); > rm->data.op_mmp_znotifier = &info->znotif; > - if (mm_account_pinned_pages(&rm->data.op_mmp_znotifier->z_mmp, > + vm_account_init(vm_account, current, current_user(), VM_ACCOUNT_USER); > + if (mm_account_pinned_pages(vm_account, > + &rm->data.op_mmp_znotifier->z_mmp, > length)) { > ret = -ENOMEM; > goto err; > @@ -399,7 +402,7 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter * > for (i = 0; i < rm->data.op_nents; i++) > put_page(sg_page(&rm->data.op_sg[i])); > mmp = &rm->data.op_mmp_znotifier->z_mmp; > - mm_unaccount_pinned_pages(mmp); > + mm_unaccount_pinned_pages(vm_account, mmp); > ret = -EFAULT; > goto err; > } I wonder if RDS should just not be doing accounting? Usually things related to iov_iter are short term and we don't account for them. But then I don't really know how RDS works, Santos? Regardless, maybe the vm_account should be stored in the rds_msg_zcopy_info ? Jason
Jason Gunthorpe <jgg@nvidia.com> writes: > On Tue, Jan 24, 2023 at 04:42:39PM +1100, Alistair Popple wrote: >> diff --git a/include/net/sock.h b/include/net/sock.h >> index dcd72e6..bc3a868 100644 >> --- a/include/net/sock.h >> +++ b/include/net/sock.h >> @@ -334,6 +334,7 @@ struct sk_filter; >> * @sk_security: used by security modules >> * @sk_mark: generic packet mark >> * @sk_cgrp_data: cgroup data for this cgroup >> + * @sk_vm_account: data for pinned memory accounting >> * @sk_memcg: this socket's memory cgroup association >> * @sk_write_pending: a write to stream socket waits to start >> * @sk_state_change: callback to indicate change in the state of the sock >> @@ -523,6 +524,7 @@ struct sock { >> void *sk_security; >> #endif >> struct sock_cgroup_data sk_cgrp_data; >> + struct vm_account sk_vm_account; >> struct mem_cgroup *sk_memcg; >> void (*sk_state_change)(struct sock *sk); >> void (*sk_data_ready)(struct sock *sk); > > I'm not sure this makes sense in a sock - each sock can be shared with > different proceses.. TBH it didn't feel right to me either so was hoping for some feedback. Will try your suggestion below. >> diff --git a/net/rds/message.c b/net/rds/message.c >> index b47e4f0..2138a70 100644 >> --- a/net/rds/message.c >> +++ b/net/rds/message.c >> @@ -99,7 +99,7 @@ static void rds_rm_zerocopy_callback(struct rds_sock *rs, >> struct list_head *head; >> unsigned long flags; >> >> - mm_unaccount_pinned_pages(&znotif->z_mmp); >> + mm_unaccount_pinned_pages(&rs->rs_sk.sk_vm_account, &znotif->z_mmp); >> q = &rs->rs_zcookie_queue; >> spin_lock_irqsave(&q->lock, flags); >> head = &q->zcookie_head; >> @@ -367,6 +367,7 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter * >> int ret = 0; >> int length = iov_iter_count(from); >> struct rds_msg_zcopy_info *info; >> + struct vm_account *vm_account = &rm->m_rs->rs_sk.sk_vm_account; >> >> rm->m_inc.i_hdr.h_len = cpu_to_be32(iov_iter_count(from)); >> >> @@ -380,7 +381,9 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter * >> return -ENOMEM; >> INIT_LIST_HEAD(&info->rs_zcookie_next); >> rm->data.op_mmp_znotifier = &info->znotif; >> - if (mm_account_pinned_pages(&rm->data.op_mmp_znotifier->z_mmp, >> + vm_account_init(vm_account, current, current_user(), VM_ACCOUNT_USER); >> + if (mm_account_pinned_pages(vm_account, >> + &rm->data.op_mmp_znotifier->z_mmp, >> length)) { >> ret = -ENOMEM; >> goto err; >> @@ -399,7 +402,7 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter * >> for (i = 0; i < rm->data.op_nents; i++) >> put_page(sg_page(&rm->data.op_sg[i])); >> mmp = &rm->data.op_mmp_znotifier->z_mmp; >> - mm_unaccount_pinned_pages(mmp); >> + mm_unaccount_pinned_pages(vm_account, mmp); >> ret = -EFAULT; >> goto err; >> } > > I wonder if RDS should just not be doing accounting? Usually things > related to iov_iter are short term and we don't account for them. Yeah, I couldn't easily figure out why these were accounted for in the first place either. > But then I don't really know how RDS works, Santos? > > Regardless, maybe the vm_account should be stored in the > rds_msg_zcopy_info ? On first glance that looks like a better spot. Thanks for the idea. > Jason
Alistair Popple <apopple@nvidia.com> writes: > Jason Gunthorpe <jgg@nvidia.com> writes: > >> On Tue, Jan 24, 2023 at 04:42:39PM +1100, Alistair Popple wrote: >>> diff --git a/include/net/sock.h b/include/net/sock.h >>> index dcd72e6..bc3a868 100644 >>> --- a/include/net/sock.h >>> +++ b/include/net/sock.h >>> @@ -334,6 +334,7 @@ struct sk_filter; >>> * @sk_security: used by security modules >>> * @sk_mark: generic packet mark >>> * @sk_cgrp_data: cgroup data for this cgroup >>> + * @sk_vm_account: data for pinned memory accounting >>> * @sk_memcg: this socket's memory cgroup association >>> * @sk_write_pending: a write to stream socket waits to start >>> * @sk_state_change: callback to indicate change in the state of the sock >>> @@ -523,6 +524,7 @@ struct sock { >>> void *sk_security; >>> #endif >>> struct sock_cgroup_data sk_cgrp_data; >>> + struct vm_account sk_vm_account; >>> struct mem_cgroup *sk_memcg; >>> void (*sk_state_change)(struct sock *sk); >>> void (*sk_data_ready)(struct sock *sk); >> >> I'm not sure this makes sense in a sock - each sock can be shared with >> different proceses.. > > TBH it didn't feel right to me either so was hoping for some > feedback. Will try your suggestion below. > >>> diff --git a/net/rds/message.c b/net/rds/message.c >>> index b47e4f0..2138a70 100644 >>> --- a/net/rds/message.c >>> +++ b/net/rds/message.c >>> @@ -99,7 +99,7 @@ static void rds_rm_zerocopy_callback(struct rds_sock *rs, >>> struct list_head *head; >>> unsigned long flags; >>> >>> - mm_unaccount_pinned_pages(&znotif->z_mmp); >>> + mm_unaccount_pinned_pages(&rs->rs_sk.sk_vm_account, &znotif->z_mmp); >>> q = &rs->rs_zcookie_queue; >>> spin_lock_irqsave(&q->lock, flags); >>> head = &q->zcookie_head; >>> @@ -367,6 +367,7 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter * >>> int ret = 0; >>> int length = iov_iter_count(from); >>> struct rds_msg_zcopy_info *info; >>> + struct vm_account *vm_account = &rm->m_rs->rs_sk.sk_vm_account; >>> >>> rm->m_inc.i_hdr.h_len = cpu_to_be32(iov_iter_count(from)); >>> >>> @@ -380,7 +381,9 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter * >>> return -ENOMEM; >>> INIT_LIST_HEAD(&info->rs_zcookie_next); >>> rm->data.op_mmp_znotifier = &info->znotif; >>> - if (mm_account_pinned_pages(&rm->data.op_mmp_znotifier->z_mmp, >>> + vm_account_init(vm_account, current, current_user(), VM_ACCOUNT_USER); >>> + if (mm_account_pinned_pages(vm_account, >>> + &rm->data.op_mmp_znotifier->z_mmp, >>> length)) { >>> ret = -ENOMEM; >>> goto err; >>> @@ -399,7 +402,7 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter * >>> for (i = 0; i < rm->data.op_nents; i++) >>> put_page(sg_page(&rm->data.op_sg[i])); >>> mmp = &rm->data.op_mmp_znotifier->z_mmp; >>> - mm_unaccount_pinned_pages(mmp); >>> + mm_unaccount_pinned_pages(vm_account, mmp); >>> ret = -EFAULT; >>> goto err; >>> } >> >> I wonder if RDS should just not be doing accounting? Usually things >> related to iov_iter are short term and we don't account for them. > > Yeah, I couldn't easily figure out why these were accounted for in the > first place either. > >> But then I don't really know how RDS works, Santos? >> >> Regardless, maybe the vm_account should be stored in the >> rds_msg_zcopy_info ? > > On first glance that looks like a better spot. Thanks for the > idea. That works fine for RDS but not for skbuff. We still need a vm_account in the struct sock or somewhere else for that. For example in msg_zerocopy_realloc() we only have a struct ubuf_info_msgzc available. We can't add a struct vm_account field to that because ultimately it is stored in struct sk_buff->ck[] which is not large enough to contain ubuf_info_msgzc + vm_account. I'm not terribly familiar with kernel networking code though, so happy to hear other suggestions. >> Jason
On Mon, Feb 06, 2023 at 03:36:49PM +1100, Alistair Popple wrote: > >> But then I don't really know how RDS works, Santos? > >> > >> Regardless, maybe the vm_account should be stored in the > >> rds_msg_zcopy_info ? > > > > On first glance that looks like a better spot. Thanks for the > > idea. > > That works fine for RDS but not for skbuff. I would definately put the RDS stuff like that.. > We still need a vm_account in the struct sock or somewhere else for > that. For example in msg_zerocopy_realloc() we only have a struct > ubuf_info_msgzc available. We can't add a struct vm_account field to > that because ultimately it is stored in struct sk_buff->ck[] which > is not large enough to contain ubuf_info_msgzc + vm_account. Well, AFAICT this is using iov_iter to get the pages and in general iov_iter - eg as used for O_DIRECT - doesn't charge anything. If this does somehow allow a userspace to hold pin a page for a long time then it is already technically wrong because it doesn't use FOLL_LONGTERM. Arguably FOLL_LONGTERM should be the key precondition to require accounting. So I wonder if it should just be deleted? Jason
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 4c84924..c956405 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -554,7 +554,6 @@ struct ubuf_info_msgzc { }; struct mmpin { - struct user_struct *user; unsigned int num_pg; } mmp; }; @@ -563,8 +562,9 @@ struct ubuf_info_msgzc { #define uarg_to_msgzc(ubuf_ptr) container_of((ubuf_ptr), struct ubuf_info_msgzc, \ ubuf) -int mm_account_pinned_pages(struct mmpin *mmp, size_t size); -void mm_unaccount_pinned_pages(struct mmpin *mmp); +int mm_account_pinned_pages(struct vm_account *vm_account, struct mmpin *mmp, + size_t size); +void mm_unaccount_pinned_pages(struct vm_account *vm_account, struct mmpin *mmp); /* This data is invariant across clones and lives at * the end of the header data, ie. at skb->end. diff --git a/include/net/sock.h b/include/net/sock.h index dcd72e6..bc3a868 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -334,6 +334,7 @@ struct sk_filter; * @sk_security: used by security modules * @sk_mark: generic packet mark * @sk_cgrp_data: cgroup data for this cgroup + * @sk_vm_account: data for pinned memory accounting * @sk_memcg: this socket's memory cgroup association * @sk_write_pending: a write to stream socket waits to start * @sk_state_change: callback to indicate change in the state of the sock @@ -523,6 +524,7 @@ struct sock { void *sk_security; #endif struct sock_cgroup_data sk_cgrp_data; + struct vm_account sk_vm_account; struct mem_cgroup *sk_memcg; void (*sk_state_change)(struct sock *sk); void (*sk_data_ready)(struct sock *sk); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 4a0eb55..bed3fc9 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1309,42 +1309,25 @@ struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src) } EXPORT_SYMBOL_GPL(skb_morph); -int mm_account_pinned_pages(struct mmpin *mmp, size_t size) +int mm_account_pinned_pages(struct vm_account *vm_account, struct mmpin *mmp, + size_t size) { - unsigned long max_pg, num_pg, new_pg, old_pg; - struct user_struct *user; - - if (capable(CAP_IPC_LOCK) || !size) - return 0; + unsigned int num_pg; num_pg = (size >> PAGE_SHIFT) + 2; /* worst case */ - max_pg = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; - user = mmp->user ? : current_user(); + if (vm_account_pinned(vm_account, num_pg)) + return -ENOBUFS; - old_pg = atomic_long_read(&user->locked_vm); - do { - new_pg = old_pg + num_pg; - if (new_pg > max_pg) - return -ENOBUFS; - } while (!atomic_long_try_cmpxchg(&user->locked_vm, &old_pg, new_pg)); - - if (!mmp->user) { - mmp->user = get_uid(user); - mmp->num_pg = num_pg; - } else { - mmp->num_pg += num_pg; - } + mmp->num_pg += num_pg; return 0; } EXPORT_SYMBOL_GPL(mm_account_pinned_pages); -void mm_unaccount_pinned_pages(struct mmpin *mmp) +void mm_unaccount_pinned_pages(struct vm_account *vm_account, struct mmpin *mmp) { - if (mmp->user) { - atomic_long_sub(mmp->num_pg, &mmp->user->locked_vm); - free_uid(mmp->user); - } + vm_unaccount_pinned(vm_account, mmp->num_pg); + vm_account_release(vm_account); } EXPORT_SYMBOL_GPL(mm_unaccount_pinned_pages); @@ -1361,9 +1344,12 @@ static struct ubuf_info *msg_zerocopy_alloc(struct sock *sk, size_t size) BUILD_BUG_ON(sizeof(*uarg) > sizeof(skb->cb)); uarg = (void *)skb->cb; - uarg->mmp.user = NULL; + uarg->mmp.num_pg = 0; + vm_account_init(&sk->sk_vm_account, current, + current_user(), VM_ACCOUNT_USER); - if (mm_account_pinned_pages(&uarg->mmp, size)) { + if (mm_account_pinned_pages(&sk->sk_vm_account, &uarg->mmp, size)) { + vm_account_release(&sk->sk_vm_account); kfree_skb(skb); return NULL; } @@ -1416,7 +1402,8 @@ struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size, next = (u32)atomic_read(&sk->sk_zckey); if ((u32)(uarg_zc->id + uarg_zc->len) == next) { - if (mm_account_pinned_pages(&uarg_zc->mmp, size)) + if (mm_account_pinned_pages(&sk->sk_vm_account, + &uarg_zc->mmp, size)) return NULL; uarg_zc->len++; uarg_zc->bytelen = bytelen; @@ -1466,7 +1453,7 @@ static void __msg_zerocopy_callback(struct ubuf_info_msgzc *uarg) u32 lo, hi; u16 len; - mm_unaccount_pinned_pages(&uarg->mmp); + mm_unaccount_pinned_pages(&sk->sk_vm_account, &uarg->mmp); /* if !len, there was only 1 call, and it was aborted * so do not queue a completion notification diff --git a/net/rds/message.c b/net/rds/message.c index b47e4f0..2138a70 100644 --- a/net/rds/message.c +++ b/net/rds/message.c @@ -99,7 +99,7 @@ static void rds_rm_zerocopy_callback(struct rds_sock *rs, struct list_head *head; unsigned long flags; - mm_unaccount_pinned_pages(&znotif->z_mmp); + mm_unaccount_pinned_pages(&rs->rs_sk.sk_vm_account, &znotif->z_mmp); q = &rs->rs_zcookie_queue; spin_lock_irqsave(&q->lock, flags); head = &q->zcookie_head; @@ -367,6 +367,7 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter * int ret = 0; int length = iov_iter_count(from); struct rds_msg_zcopy_info *info; + struct vm_account *vm_account = &rm->m_rs->rs_sk.sk_vm_account; rm->m_inc.i_hdr.h_len = cpu_to_be32(iov_iter_count(from)); @@ -380,7 +381,9 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter * return -ENOMEM; INIT_LIST_HEAD(&info->rs_zcookie_next); rm->data.op_mmp_znotifier = &info->znotif; - if (mm_account_pinned_pages(&rm->data.op_mmp_znotifier->z_mmp, + vm_account_init(vm_account, current, current_user(), VM_ACCOUNT_USER); + if (mm_account_pinned_pages(vm_account, + &rm->data.op_mmp_znotifier->z_mmp, length)) { ret = -ENOMEM; goto err; @@ -399,7 +402,7 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter * for (i = 0; i < rm->data.op_nents; i++) put_page(sg_page(&rm->data.op_sg[i])); mmp = &rm->data.op_mmp_znotifier->z_mmp; - mm_unaccount_pinned_pages(mmp); + mm_unaccount_pinned_pages(vm_account, mmp); ret = -EFAULT; goto err; }
Switch to using vm_account to charge pinned pages. This will allow a future change to charge the pinned pages to a cgroup to limit the overall number of pinned pages in the system. Signed-off-by: Alistair Popple <apopple@nvidia.com> Cc: linux-kernel@vger.kernel.org Cc: netdev@vger.kernel.org Cc: linux-rdma@vger.kernel.org Cc: rds-devel@oss.oracle.com --- include/linux/skbuff.h | 6 ++--- include/net/sock.h | 2 ++- net/core/skbuff.c | 47 +++++++++++++++---------------------------- net/rds/message.c | 9 +++++--- 4 files changed, 28 insertions(+), 36 deletions(-)