When automounting, the fs_context should be fixed up to use the cred
from the parent filesystem, since the operation is just extending the
namespace. Authorisation to enter that namespace will already have been
provided by the preceding lookup.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Only inherit the block sizes that were actually specified as mount
parameters for the parent mount.
Fixes: 62a55d088c ("NFS: Additional refactoring for fs_context conversion")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
When a filesystem is being automounted, it needs to preserve the
user-set superblock mount options, such as the "ro" flag.
Reported-by: Li Lingfeng <lilingfeng3@huawei.com>
Link: https://lore.kernel.org/all/20240604112636.236517-3-lilingfeng@huaweicloud.com/
Fixes: f2aedb713c ("NFS: Add fs_context support.")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This reverts commit 52cb7f8f17.
Silently ignoring the "ro" and "rw" mount options causes user confusion,
and regressions.
Reported-by: Alkis Georgopoulos<alkisg@gmail.com>
Cc: Li Lingfeng <lilingfeng3@huawei.com>
Fixes: 52cb7f8f17 ("nfs: ignore SB_RDONLY when mounting nfs")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This reverts commit 8cd9b78594.
Silently ignoring the "ro" and "rw" mount options causes user confusion,
and regressions.
Reported-by: Alkis Georgopoulos<alkisg@gmail.com>
Cc: Li Lingfeng <lilingfeng3@huawei.com>
Fixes: 8cd9b78594 ("nfs: clear SB_RDONLY before getting superblock")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This reverts commit 80c4de6ab4.
Silently ignoring the "ro" and "rw" mount options causes user confusion,
and regressions.
Reported-by: Alkis Georgopoulos<alkisg@gmail.com>
Cc: Li Lingfeng <lilingfeng3@huawei.com>
Fixes: 80c4de6ab4 ("nfs: ignore SB_RDONLY when remounting nfs")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Replace the raw use of 500 value in schedule_timeout() function with
msecs_to_jiffies() to ensure intended value across different kernel
configurations regardless of HZ value.
Signed-off-by: Shi Hao <i.shihao.999@gmail.com>
Link: https://patch.msgid.link/20251117200949.42557-1-i.shihao.999@gmail.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The "wcss_q6_bcr_reset" is not used on IPQ8074, and IPQ6018. Use
devm_reset_control_get_optional_exclusive() for this reset so that
probe() does not fail on platforms where it is not used.
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Link: https://lore.kernel.org/r/20251129013207.3981517-2-mr.nuke.me@gmail.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
The "qcom,halt-regs" consists of a phandle reference followed by the
three offsets within syscon for halt registers. Thus, we need to
request 4 integers from of_property_read_variable_u32_array(), with
the halt_reg ofsets at indexes 1, 2, and 3. Offset 0 is the phandle.
With MAX_HALT_REG at 3, of_property_read_variable_u32_array() returns
-EOVERFLOW, causing .probe() to fail.
Increase MAX_HALT_REG to 4, and update the indexes accordingly.
Fixes: 0af65b9b91 ("remoteproc: qcom: wcss: Add non pas wcss Q6 support for QCS404")
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Link: https://lore.kernel.org/r/20251129013207.3981517-1-mr.nuke.me@gmail.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
'tpm2_load_cmd' allocates a tempoary blob indirectly via 'tpm2_key_decode'
but it is not freed in the failure paths. Address this by wrapping the blob
into with a cleanup helper.
Cc: stable@vger.kernel.org # v5.13+
Fixes: f221974525 ("security: keys: trusted: use ASN.1 TPM2 key format for the blobs")
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
'trusted_tpm2' duplicates 'tpm2_hash_map' originally part of the TPN
driver, which is suboptimal.
Implement and export `tpm2_find_hash_alg()` in the driver, and substitute
the redundant code in 'trusted_tpm2' with a call to the new function.
Reviewed-by: Jonathan McDowell <noodles@meta.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
A dynamic remove/add storage adapter test hits EEH on PowerPC:
EEH: [c00000000004f77c] __eeh_send_failure_event+0x7c/0x160
EEH: [c000000000048464] eeh_dev_check_failure.part.0+0x254/0x660
EEH: [c000000000934e0c] __pci_read_msi_msg+0x1ac/0x280
EEH: [c000000000100f68] pseries_msi_compose_msg+0x28/0x40
EEH: [c00000000020e1cc] irq_chip_compose_msi_msg+0x5c/0x90
EEH: [c000000000214b1c] msi_domain_set_affinity+0xbc/0x100
EEH: [c000000000206be4] irq_do_set_affinity+0x214/0x2c0
EEH: [c000000000206e04] irq_set_affinity_locked+0x174/0x230
EEH: [c000000000207044] irq_set_affinity+0x64/0xa0
EEH: [c000000000212890] write_irq_affinity.constprop.0.isra.0+0x130/0x150
EEH: [c00000000068868c] proc_reg_write+0xfc/0x160
EEH: [c0000000005adb48] vfs_write+0xf8/0x4e0
EEH: [c0000000005ae234] ksys_write+0x84/0x140
EEH: [c00000000002e994] system_call_exception+0x164/0x310
EEH: [c00000000000bfe8] system_call_vectored_common+0xe8/0x278
The irqbalance daemon kicks in before invoking qla2xxx->slot_reset
during the EEH recovery process.
irqbalance daemon
->irq_set_affinity()
->msi_domain_set_affinity()
->irq_chip_set_affiinity_parent()
->xive_irq_set_affinity()
->pseries_msi_compose_ms()
->__pci_read_msi_msg()
->irq_chip_compose_msi_msg()
In __pci_read_msi_msg(), the first MSI-X vector is set to all F by the
irqbalance daemon. pci_write_msg_msix: index=0, lo=ffffffff hi=fffffff
IRQ balancing is not required during adapter reset.
Enable "IRQ_NO_BALANCING" bit before starting adapter reset and disable
it calling pci_restore_state(). The irqbalance daemon is disabled for
this short period of time (~2s).
Co-developed-by: Kyle Mahlkuch <Kyle.Mahlkuch@ibm.com>
Signed-off-by: Kyle Mahlkuch <Kyle.Mahlkuch@ibm.com>
Signed-off-by: Wen Xiong <wenxiong@linux.ibm.com>
Link: https://patch.msgid.link/20251028142427.3969819-3-wenxiong@linux.ibm.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The delayed work item 'imm_tq' is initialized in imm_attach() and
scheduled via imm_queuecommand() for processing SCSI commands. When the
IMM parallel port SCSI host adapter is detached through imm_detach(),
the imm_struct device instance is deallocated.
However, the delayed work might still be pending or executing
when imm_detach() is called, leading to use-after-free bugs
when the work function imm_interrupt() accesses the already
freed imm_struct memory.
The race condition can occur as follows:
CPU 0(detach thread) | CPU 1
| imm_queuecommand()
| imm_queuecommand_lck()
imm_detach() | schedule_delayed_work()
kfree(dev) //FREE | imm_interrupt()
| dev = container_of(...) //USE
dev-> //USE
Add disable_delayed_work_sync() in imm_detach() to guarantee proper
cancellation of the delayed work item before imm_struct is deallocated.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://patch.msgid.link/20251028100149.40721-1-duoming@zju.edu.cn
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The KMSG_COMPONENT macro is a leftover of the s390 specific "kernel
message catalog" from 2008 [1] which never made it upstream.
The macro was added to s390 code to allow for an out-of-tree patch which
used this to generate unique message ids. Also this out-of-tree doesn't
exist anymore.
The pattern of how the KMSG_COMPONENT is used was partially also used
for non s390 specific code, for whatever reasons.
Remove the macro in order to get rid of a pointless indirection.
[1] https://lwn.net/Articles/292650/
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://patch.msgid.link/20251126144027.2213895-1-hca@linux.ibm.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Recent changes in the linux-next kernel will add new field for syscalls
to have contents in the userspace like below.
# cat /sys/kernel/tracing/events/syscalls/sys_enter_write/format
name: sys_enter_write
ID: 758
format:
field:unsigned short common_type; offset:0; size:2; signed:0;
field:unsigned char common_flags; offset:2; size:1; signed:0;
field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
field:int common_pid; offset:4; size:4; signed:1;
field:int __syscall_nr; offset:8; size:4; signed:1;
field:unsigned int fd; offset:16; size:8; signed:0;
field:const char * buf; offset:24; size:8; signed:0;
field:size_t count; offset:32; size:8; signed:0;
field:__data_loc char[] __buf_val; offset:40; size:4; signed:0;
print fmt: "fd: 0x%08lx, buf: 0x%08lx (%s), count: 0x%08lx", ((unsigned long)(REC->fd)),
((unsigned long)(REC->buf)), __print_dynamic_array(__buf_val, 1),
((unsigned long)(REC->count))
We have a different way to handle those arguments and this change
confuses perf trace then make some tests failing. Fix it by skipping
the new fields that have "__data_loc char[]" type.
Maybe we can switch to this instead of the BPF augmentation later.
Reviewed-by: Howard Chu <howardchu95@gmail.com>
Tested-by: Thomas Richter <tmricht@linux.ibm.com>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Howard Chu <howardchu95@gmail.com>
Reported-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
If scsi_device_quiesce() returns zero, the function executed successfully.
Signed-off-by: Miao Li <limiao@kylinos.cn>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://patch.msgid.link/20251124075444.32699-1-limiao870622@163.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
If allocation of cmd->t_task_cdb fails, it remains NULL but is later
dereferenced in the 'err' path.
In case of error, reset NULL t_task_cdb value to point at the default
fixed-size buffer.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 9e95fb805d ("scsi: target: Fix NULL pointer dereference")
Cc: stable@vger.kernel.org
Signed-off-by: Andrey Vatoropin <a.vatoropin@crpt.ru>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Link: https://patch.msgid.link/20251118084014.324940-1-a.vatoropin@crpt.ru
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
When a W-LUN resume fails, its parent devices in the SCSI hierarchy,
including the scsi_target, may be runtime suspended. Subsequently, the
error handler in ufshcd_recover_pm_error() fails to set the W-LUN device
back to active because the parent target is not active. This results in
the following errors:
google-ufshcd 3c2d0000.ufs: ufshcd_err_handler started; HBA state eh_fatal; ...
ufs_device_wlun 0:0:0:49488: START_STOP failed for power mode: 1, result 40000
ufs_device_wlun 0:0:0:49488: ufshcd_wl_runtime_resume failed: -5
...
ufs_device_wlun 0:0:0:49488: runtime PM trying to activate child device 0:0:0:49488 but parent (target0:0:0) is not active
Address this by:
1. Ensuring the W-LUN's parent scsi_target is runtime resumed before
attempting to set the W-LUN to active within
ufshcd_recover_pm_error().
2. Explicitly checking for power.runtime_error on the HBA and W-LUN
devices before calling pm_runtime_set_active() to clear the error
state.
3. Adding pm_runtime_get_sync(hba->dev) in
ufshcd_err_handling_prepare() to ensure the HBA itself is active
during error recovery, even if a child device resume failed.
These changes ensure the device power states are managed correctly
during error recovery.
Signed-off-by: Brian Kao <powenkao@google.com>
Tested-by: Brian Kao <powenkao@google.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251112063214.1195761-1-powenkao@google.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
If we get a signal, we need to restore the vm_refcnt. We don't think that
the refcount can actually be decremented to zero here as it requires the
VMA to be detached, and the vma_mark_detached() uses TASK_UNINTERRUPTIBLE.
However, that's a bit subtle, so handle it as if the refcount was zero at
the start of this function.
Link: https://lkml.kernel.org/r/20251128040100.3022561-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: syzbot+5b19bad23ac7f44bf8b8@syzkaller.appspotmail.com
Fixes: 2197bb60f8 ("mm: add vma_start_write_killable()")
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The loop breaks immediately after finding the first swap device and
never modifies the list. Replace plist_for_each_entry_safe() with
plist_for_each_entry() and remove the unused next variable.
Link: https://lkml.kernel.org/r/20251127100303.783198-3-youngjun.park@lge.com
Signed-off-by: Youngjun Park <youngjun.park@lge.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Kairui Song <kasong@tencent.com>
Acked-by: Chris Li <chrisl@kernel.org>
Cc: Barry Song <baohua@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/swapfile: fix and cleanup swap list iterations", v2.
This series fixes a potential list iteration issue in swap_sync_discard()
when devices are removed, and includes a cleanup for
__folio_throttle_swaprate().
This patch (of 2):
When the next node is removed from the plist (e.g. by swapoff),
plist_del() makes the node point to itself, causing the iteration to loop
on the same entry indefinitely.
Add a plist_node_empty() check to detect this case and restart iteration,
allowing swap_sync_discard() to continue processing remaining swap devices
that still have pending discard entries.
Additionally, switch from swap_avail_lock/swap_avail_head to
swap_lock/swap_active_head so that iteration is only affected by swapoff
operations rather than frequent availability changes, reducing exceptional
condition checks and lock contention.
Link: https://lkml.kernel.org/r/20251127100303.783198-1-youngjun.park@lge.com
Link: https://lkml.kernel.org/r/20251127100303.783198-2-youngjun.park@lge.com
Fixes: 686ea517f471 ("mm, swap: do not perform synchronous discard during allocation")
Signed-off-by: Youngjun Park <youngjun.park@lge.com>
Suggested-by: Kairui Song <kasong@tencent.com>
Acked-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
During system shutdown, KFENCE can cause IPI synchronization issues if it
remains active through the reboot process. To prevent this, register a
reboot notifier that disables KFENCE and cancels any pending timer work
early in the shutdown sequence.
This is only necessary when CONFIG_KFENCE_STATIC_KEYS is enabled, as this
configuration sends IPIs that can interfere with shutdown. Without static
keys, no IPIs are generated and KFENCE can safely remain active.
The notifier uses maximum priority (INT_MAX) to ensure KFENCE shuts down
before other subsystems that might still depend on stable memory
allocation behavior.
This fixes a late kexec CSD lockup[1] when kfence is trying to IPI a CPU
that is busy in a IRQ-disabled context printing characters to the console.
Link: https://lkml.kernel.org/r/20251127-kfence-v2-1-daeccb5ef9aa@debian.org
Link: https://lkml.kernel.org/r/20251126-kfence-v1-1-5a6e1d7c681c@debian.org
Link: https://lore.kernel.org/all/sqwajvt7utnt463tzxgwu2yctyn5m6bjwrslsnupfexeml6hkd@v6sqmpbu3vvu/ [1]
Fixes: 0ce20dd840 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The dec_lruvec_kmem_state helper is unused by any caller and can be safely
removed. Meanwhile, the inc_lruvec_kmem_state helper is only referenced
by shadow_lru_isolate, retaining these two helpers is unnecessary. This
patch removes both helper functions to eliminate redundant code.
Link: https://lkml.kernel.org/r/20251126020435.1511637-1-chenridong@huaweicloud.com
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Acked-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Lu Jialin <lujialin4@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In "uffd-stress.c" & "uffd-unit-tests.c". address of char variable having
garbage value (uninitialized) is passed to 'write' syscall triggers
warning.
uffd-stress.c:246:39: warning: variable 'c' is uninitialized when
passed as a const pointer argument here
[-Wuninitialized-const-pointer]
uffd-unit-tests.c:581:31: warning: variable 'c' is uninitialized
when passed as a const pointer argument here
[-Wuninitialized-const-pointer]
so the fix is to assign char variable to '\0' to prevent writing of
garbage value.
Link: https://lkml.kernel.org/r/20251126160830.52124-1-ankitkhushwaha.linux@gmail.com
Signed-off-by: Ankit Khushwaha <ankitkhushwaha.linux@gmail.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Most of the DEBUG_RODATA_TEST section is indented by four spaces instead
of the customary single TAB.
Link: https://lkml.kernel.org/r/74f39b1bffc6ed802088cb3e7d17b4c82330e8b3.1764058676.git.geert@linux-m68k.org
Fixes: 2959a5f726 ("mm: add arch-independent testcases for RODATA")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Jinbum Park <jinb.park7@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
It is useful to transition to using a bitmap for VMA flags so we can avoid
running out of flags, especially for 32-bit kernels which are constrained
to 32 flags, necessitating some features to be limited to 64-bit kernels
only.
By doing so, we remove any constraint on the number of VMA flags moving
forwards no matter the platform and can decide in future to extend beyond
64 if required.
We start by declaring an opaque types, vma_flags_t (which resembles
mm_struct flags of type mm_flags_t), setting it to precisely the same size
as vm_flags_t, and place it in union with vm_flags in the VMA declaration.
We additionally update struct vm_area_desc equivalently placing the new
opaque type in union with vm_flags.
This change therefore does not impact the size of struct vm_area_struct or
struct vm_area_desc.
In order for the change to be iterative and to avoid impacting
performance, we designate VM_xxx declared bitmap flag values as those
which must exist in the first system word of the VMA flags bitmap.
We therefore declare vma_flags_clear_all(), vma_flags_overwrite_word(),
vma_flags_overwrite_word(), vma_flags_overwrite_word_once(),
vma_flags_set_word() and vma_flags_clear_word() in order to allow us to
update the existing vm_flags_*() functions to utilise these helpers.
This is a stepping stone towards converting users to the VMA flags bitmap
and behaves precisely as before.
By doing this, we can eliminate the existing private vma->__vm_flags field
in the vma->vm_flags union and replace it with the newly introduced opaque
type vma_flags, which we call flags so we refer to the new bitmap field as
vma->flags.
We update vma_flag_[test, set]_atomic() to account for the change also.
We adapt vm_flags_reset_once() to only clear those bits above the first
system word providing write-once semantics to the first system word (which
it is presumed the caller requires - and in all current use cases this is
so).
As we currently only specify that the VMA flags bitmap size is equal to
BITS_PER_LONG number of bits, this is a noop, but is defensive in
preparation for a future change that increases this.
We additionally update the VMA userland test declarations to implement the
same changes there.
Finally, we update the rust code to reference vma->vm_flags on update
rather than vma->__vm_flags which has been removed. This is safe for now,
albeit it is implicitly performing a const cast.
Once we introduce flag helpers we can improve this more.
No functional change intended.
Link: https://lkml.kernel.org/r/bab179d7b153ac12f221b7d65caac2759282cfe9.1764064557.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: Alice Ryhl <aliceryhl@google.com> [rust]
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Björn Roy Baron <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Trevor Gross <tmgross@umich.edu>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Wei Xu <weixugc@google.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The userland VMA test code relied on an internal implementation detail -
the existence of vma->__vm_flags to directly access VMA flags. There is
no need to do so when we have the vm_flags_*() helper functions available.
This is ugly, but also a subsequent commit will eliminate this field
altogether so this will shortly become broken.
This patch has us utilise the helper functions instead.
Link: https://lkml.kernel.org/r/6275c53a6bb20743edcbe92d3e130183b47d18d0.1764064557.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: Alice Ryhl <aliceryhl@google.com> [rust]
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Björn Roy Baron <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Trevor Gross <tmgross@umich.edu>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Wei Xu <weixugc@google.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The __mm_flags_set_word() function is slightly ambiguous - we use 'set' to
refer to setting individual bits (such as in mm_flags_set()) but here we
use it to refer to overwriting the value altogether.
Rename it to __mm_flags_overwrite_word() to eliminate this ambiguity.
We additionally simplify the functions, eliminating unnecessary
bitmap_xxx() operations (the compiler would have optimised these out but
it's worth being as clear as we can be here).
Link: https://lkml.kernel.org/r/8f0bc556e1b90eca8ea5eba41f8d5d3f9cd7c98a.1764064557.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: Alice Ryhl <aliceryhl@google.com> [rust]
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Björn Roy Baron <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Trevor Gross <tmgross@umich.edu>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Wei Xu <weixugc@google.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "initial work on making VMA flags a bitmap", v3.
We are in the rather silly situation that we are running out of VMA flags
as they are currently limited to a system word in size.
This leads to absurd situations where we limit features to 64-bit
architectures only because we simply do not have the ability to add a flag
for 32-bit ones.
This is very constraining and leads to hacks or, in the worst case, simply
an inability to implement features we want for entirely arbitrary reasons.
This also of course gives us something of a Y2K type situation in mm where
we might eventually exhaust all of the VMA flags even on 64-bit systems.
This series lays the groundwork for getting away from this limitation by
establishing VMA flags as a bitmap whose size we can increase in future
beyond 64 bits if required.
This is necessarily a highly iterative process given the extensive use of
VMA flags throughout the kernel, so we start by performing basic steps.
Firstly, we declare VMA flags by bit number rather than by value,
retaining the VM_xxx fields but in terms of these newly introduced
VMA_xxx_BIT fields.
While we are here, we use sparse annotations to ensure that, when dealing
with VMA bit number parameters, we cannot be passed values which are not
declared as such - providing some useful type safety.
We then introduce an opaque VMA flag type, much like the opaque mm_struct
flag type introduced in commit bb6525f2f8 ("mm: add bitmap mm->flags
field"), which we establish in union with vma->vm_flags (but still set at
system word size meaning there is no functional or data type size change).
We update the vm_flags_xxx() helpers to use this new bitmap, introducing
sensible helpers to do so.
This series lays the foundation for further work to expand the use of
bitmap VMA flags and eventually eliminate these arbitrary restrictions.
This patch (of 4):
In order to lay the groundwork for VMA flags being a bitmap rather than a
system word in size, we need to be able to consistently refer to VMA flags
by bit number rather than value.
Take this opportunity to do so in an enum which we which is additionally
useful for tooling to extract metadata from.
This additionally makes it very clear which bits are being used for what
at a glance.
We use the VMA_ prefix for the bit values as it is logical to do so since
these reference VMAs. We consistently suffix with _BIT to make it clear
what the values refer to.
We declare bit values even when the flags that use them would not be
enabled by config options as this is simply clearer and clearly defines
what bit numbers are used for what, at no additional cost.
We declare a sparse-bitwise type vma_flag_t which ensures that users can't
pass around invalid VMA flags by accident and prepares for future work
towards VMA flags being a bitmap where we want to ensure bit values are
type safe.
To make life easier, we declare some macro helpers - DECLARE_VMA_BIT()
allows us to avoid duplication in the enum bit number declarations (and
maintaining the sparse __bitwise attribute), and INIT_VM_FLAG() is used to
assist with declaration of flags.
Unfortunately we can't declare both in the enum, as we run into issue with
logic in the kernel requiring that flags are preprocessor definitions, and
additionally we cannot have a macro which declares another macro so we
must define each flag macro directly.
Additionally, update the VMA userland testing vma_internal.h header to
include these changes.
We also have to fix the parameters to the vma_flag_*_atomic() functions
since VMA_MAYBE_GUARD_BIT is now of type vma_flag_t and sparse will
complain otherwise.
We have to update some rather silly if-deffery found in mm/task_mmu.c
which would otherwise break.
Finally, we update the rust binding helper as now it cannot auto-detect
the flags at all.
Link: https://lkml.kernel.org/r/cover.1764064556.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/3a35e5a0bcfa00e84af24cbafc0653e74deda64a.1764064556.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: Alice Ryhl <aliceryhl@google.com> [rust]
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Björn Roy Baron <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Trevor Gross <tmgross@umich.edu>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Wei Xu <weixugc@google.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The spelling of the word "relases" is incorrect; it should be "releases".
Link: https://lkml.kernel.org/r/20251125020522.1913-1-chuguangqing@inspur.com
Signed-off-by: Chu Guangqing <chuguangqing@inspur.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
calculate_totalreserve_pages() currently finds the maximum
lowmem_reserve[j] for a zone by scanning the full forward range [j =
zone_idx .. MAX_NR_ZONES). However, for a given zone i, the
lowmem_reserve[j] array (for j > i) is naturally expected to form a
monotonically non-decreasing sequence in j, not as an implementation
detail, but as a consequence that naturally arises from the semantics of
lowmem_reserve[].
For zone "i", lowmem_reserve[j] expresses how many pages in zone i must
effectively be kept in reserve when deciding whether an allocation class
that may allocate from zones up to j is allowed to fall back into i. It
protects less flexible allocation classes (which cannot use higher zones)
from being starved by more flexible ones.
Viewed from this semantics, it is natural to expect a partial ordering in
j: as j increases, the allocation class gains access to a strictly larger
set of fallback zones. Therefore lowmem_reserve[j] is expected to be
monotonically non-decreasing in j: more flexible allocation classes must
not be allowed to deplete low zones more aggressively than less flexible
ones.
In other words, if lowmem_reserve[j] were ever observed to *decrease* as j
grows, that would be unexpected from the reserve semantics' point of view
and would likely indicate a semantic change or a misconfiguration.
The current implementation in setup_per_zone_lowmem_reserve() reflects
this policy by accumulating managed pages from higher zones and applying
the configured ratio, which results in a non-decreasing sequence. This
patch makes calculate_totalreserve_pages() rely on that monotonicity
explicitly and finds the maximum reserve value by scanning backward and
stopping at the first non-zero entry. This avoids unnecessary iteration
and reflects the conceptual model more directly. No functional behavior
changes.
To maintain this assumption explicitly, a comment is added next to
setup_per_zone_lowmem_reserve() documenting the monotonicity expectation
and noting that calculate_totalreserve_pages() relies on it.
Link: https://lkml.kernel.org/r/tencent_EB0FED91B01B1F8B6DAEE96719C5F5797F07@qq.com
Signed-off-by: fujunjie <fujunjie1@qq.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We have a colocation cluster used for deploying both offline and online
services simultaneously. In this environment, we encountered a
scenario where direct memory reclamation was triggered due to kswapd
not running.
1. When applications start up, rapidly consume memory, or experience
network traffic bursts, the kernel reaches steal_suitable_fallback(),
which sets watermark_boost and subsequently wakes kswapd.
2. In the core logic of kswapd thread (balance_pgdat()), when reclaim is
triggered by watermark_boost, the maximum priority is 10. Higher
priority values mean less aggressive LRU scanning, which can result in
no pages being reclaimed during a single scan cycle:
if (nr_boost_reclaim && sc.priority == DEF_PRIORITY - 2)
raise_priority = false;
3. Additionally, many of our pods are configured with memory.low, which
prevents memory reclamation in certain cgroups, further increasing the
chance of failing to reclaim memory.
4. This eventually causes pgdat->kswapd_failures to continuously
accumulate, exceeding MAX_RECLAIM_RETRIES, and consequently kswapd
stops working. At this point, the system's available memory is still
significantly above the high watermark -- it's inappropriate for kswapd
to stop under these conditions.
The final observable issue is that a brief period of rapid memory
allocation causes kswapd to stop running, ultimately triggering direct
reclaim and making the applications unresponsive.
This problem leading to direct memory reclamation has been a
long-standing issue in our production environment. We initially held
the simple assumption that it was caused by applications allocating
memory too rapidly for kswapd to keep up with reclamation. However,
after we began monitoring kswapd's runtime behavior, we discovered a
different pattern:
kswapd initially exhibits very aggressive activity even when there is
still considerable free memory, but it subsequently stops running
entirely, even as memory levels approach the low watermark.
In summary, both boosted watermarks and memory.low increase the
probability of kswapd operation failures.
This patch specifically addresses the scenario involving boosted
watermarks by not incrementing kswapd_failures when reclamation fails.
A more general solution, potentially addressing memory.low or other
cases, requires further discussion.
Link: https://lkml.kernel.org/r/53de0b3ee0b822418e909db29bfa6513faff9d36@linux.dev
Link: https://lkml.kernel.org/r/20251024022711.382238-1-jiayuan.chen@linux.dev
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Updating a BPF_MAP_TYPE_HASH_OF_MAPS or BPF_MAP_TYPE_ARRAY_OF_MAPS via
bpf_map_update_elem() is very expensive.
In one of our workloads, we're inserting ~1400 maps of type
BPF_MAP_TYPE_ARRAY into a BPF_MAP_TYPE_ARRAY_OF_MAPS. This takes ~21
seconds on a single thread, with an average of ~15ms per call:
Function Name: map_update_elem
Number of calls: 1369
Total time: 21s 182ms 966µs
Maximum: 47ms 937µs
Average: 15ms 473µs
Minimum: 7µs
Profiling shows that nearly all of this time is going to synchronize_rcu(),
via maybe_wait_bpf_programs() in map_update_elem().
The call to synchronize_rcu() is done to ensure that after
bpf_map_update_elem() returns, no BPF programs are still looking at the old
value of the map, per commit 1ae80cf319 ("bpf: wait for running BPF
programs when updating map-in-map").
As discussed on the bpf mailing list, replace synchronize_rcu() with
synchronize_rcu_expedited(). This is 175x faster: it now takes an average
of 88 microseconds per call, for a total of 127 milliseconds in the same
benchmark:
Function Name: map_update_elem
Number of calls: 1439
Total time: 127ms 626µs
Maximum: 445µs
Average: 88µs
Minimum: 10µs
Link: https://lore.kernel.org/bpf/CAH6OuBR=w2kybK6u7aH_35B=Bo1PCukeMZefR=7V4Z2tJNK--Q@mail.gmail.com/
Signed-off-by: Ritesh Oedayrajsingh Varma <ritesh@superluminal.eu>
Link: https://lore.kernel.org/r/20251128000422.20462-1-ritesh@superluminal.eu
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Alexis Lothoré says:
====================
selftests/bpf: convert test_tc_edt.sh into test_progs
Hello,
this is a (late) v2 to my first attempt to convert the test_tc_edt
script to test_progs. This new version is way simpler, thanks to
Martin's suggestion about properly using the existing network_helpers
rather than reinventing the wheel. It also fixes a small bug in the
measured effective rate.
The converted test roughly follows the original script logic, with two
veths in two namespaces, a TCP connection between a client and a server,
and the client pushing a specific amount of data. Time is recorded
before and after the transmission to compute the effective rate.
There are two knobs driving the robustness of the test in CI:
- the amount of pushed data (the higher, the more precise is the
effective rate)
- the tolerated error margin
The original test was configured with a 20s duration and a 1% error
margin. The new test is configured with 1MB of data being pushed and a
2% error margin, to:
- make the duration tolerable in CI
- while keeping enough margin for rate measure fluctuations depending on
the CI machines load
This has been run multiple times locally to ensure that those values are
sane, and once in CI before sending the series, but I suggest to let it
live a few days in CI to see how it really behaves.
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Changes in v2:
- drop custom client/server management
- update bpf program now that server pushes data
- fix effective rate computation
- Link to v1: https://lore.kernel.org/r/20251031-tc_edt-v1-0-5d34a5823144@bootlin.com
---
Alexis Lothoré (eBPF Foundation) (4):
selftests/bpf: rename test_tc_edt.bpf.c section to expose program type
selftests/bpf: integrate test_tc_edt into test_progs
selftests/bpf: remove test_tc_edt.sh
selftests/bpf: do not hardcode target rate in test_tc_edt BPF program
tools/testing/selftests/bpf/Makefile | 2 -
.../testing/selftests/bpf/prog_tests/test_tc_edt.c | 145 +++++++++++++++++++++
tools/testing/selftests/bpf/progs/test_tc_edt.c | 11 +-
tools/testing/selftests/bpf/test_tc_edt.sh | 100 --------------
4 files changed, 151 insertions(+), 107 deletions(-)
---
base-commit: 233a075a1b27070af76d64541cf001340ecff917
change-id: 20251030-tc_edt-3ea8e8d3d14e
Best regards,
====================
Link: https://patch.msgid.link/20251128-tc_edt-v2-0-26db48373e73@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
test_tc_edt currently defines the target rate in both the userspace and
BPF parts. This value could be defined once in the userspace part if we
make it able to configure the BPF program before starting the test.
Add a target_rate variable in the BPF part, and make the userspace part
set it to the desired rate before attaching the shaping program.
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Link: https://lore.kernel.org/r/20251128-tc_edt-v2-4-26db48373e73@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Now that test_tc_edt has been integrated in test_progs, remove the
legacy shell script.
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Link: https://lore.kernel.org/r/20251128-tc_edt-v2-3-26db48373e73@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
test_tc_edt.sh uses a pair of veth and a BPF program attached to the TX
veth to shape the traffic to 5MBps. It then checks that the amount of
received bytes (at interface level), compared to the TX duration, indeed
matches 5Mbps.
Convert this test script to the test_progs framework:
- keep the double veth setup, isolated in two veths
- run a small tcp server, and connect client to server
- push a pre-configured amount of bytes, and measure how much time has
been needed to push those
- ensure that this rate is in a 2% error margin around the target rate
This two percent value, while being tight, is hopefully large enough to
not make the test too flaky in CI, while also turning it into a small
example of BPF-based shaping.
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Link: https://lore.kernel.org/r/20251128-tc_edt-v2-2-26db48373e73@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The test_tc_edt BPF program uses a custom section name, which works fine
when manually loading it with tc, but prevents it from being loaded with
libbpf.
Update the program section name to "tc" to be able to manipulate it with
a libbpf-based C test.
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Link: https://lore.kernel.org/r/20251128-tc_edt-v2-1-26db48373e73@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Kumar Kartikeya Dwivedi says:
====================
Limited queueing in NMI for rqspinlock
Ritesh reported that he was frequently seeing timeouts in cases which
should have been covered by the AA heuristics. This led to the discovery
of multiple gaps in the current code that could lead to timeouts when
AA heuristics could work to prevent them. More details and investigation
is available in the original threads. [0][1]
This set restores the ability for NMI waiters to queue in the slow path,
and reduces the cases where they would attempt to trylock. However, such
queueing must not happen when interrupting waiters which the NMI itself
depends upon for forward progress; in those cases the trylock fallback
remains, but with a single attempt to avoid aimless attempts to acquire
the lock.
It also closes a possible window in the lock fast path and the unlock
path where NMIs landing between cmpxchg and entry creation, or entry
deletion and unlock would miss the detection of an AA scenario and end
up timing out.
This virtually eliminates all the cases where existing heuristics can
prevent timeouts and quickly recover from a deadlock. More details are
available in the commit logs for each patch.
[0]: https://lore.kernel.org/bpf/CAH6OuBTjG+N=+GGwcpOUbeDN563oz4iVcU3rbse68egp9wj9_A@mail.gmail.com
[1]: https://lore.kernel.org/bpf/20251125203253.3287019-1-memxor@gmail.com
====================
Link: https://patch.msgid.link/20251128232802.1031906-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add stats to observe the success and failure rate of lock acquisition
attempts in various contexts.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20251128232802.1031906-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
