- Linux-stable-mirror - lists.linaro.org

[PATCH] intel_th: Fix error handling in intel_th_output_open

by Ma Ke

intel_th_output_open() calls bus_find_device_by_devt() which internally increments the device reference count via get_device(), but this reference is not properly released in several error paths. When device driver is unavailable, file operations cannot be obtained, or the driver's open method fails, the function returns without calling put_device(), leading to a permanent device reference count leak. This prevents the device from being properly released and could cause resource exhaustion over time. Found by code review. Cc: stable(a)vger.kernel.org Fixes: 39f4034693b7 ("intel_th: Add driver infrastructure for Intel(R) Trace Hub devices") Signed-off-by: Ma Ke <make24(a)iscas.ac.cn> --- drivers/hwtracing/intel_th/core.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c index 47d9e6c3bac0..ecc4b4ff5cf6 100644 --- a/drivers/hwtracing/intel_th/core.c +++ b/drivers/hwtracing/intel_th/core.c @@ -811,12 +811,12 @@ static int intel_th_output_open(struct inode *inode, struct file *file) dev = bus_find_device_by_devt(&intel_th_bus, inode->i_rdev); if (!dev || !dev->driver) - return -ENODEV; + goto out_no_device; thdrv = to_intel_th_driver(dev->driver); fops = fops_get(thdrv->fops); if (!fops) - return -ENODEV; + goto out_put_device; replace_fops(file, fops); @@ -824,10 +824,16 @@ static int intel_th_output_open(struct inode *inode, struct file *file) if (file->f_op->open) { err = file->f_op->open(inode, file); - return err; + if (err) + goto out_put_device; } return 0; + +out_put_device: + put_device(dev); +out_no_device: + return err; } static const struct file_operations intel_th_output_fops = { -- 2.17.1

2 days, 7 hours

2
1
0 0

[PATCH v12 1/3] NFSD: Make FILE_SYNC WRITEs comply with spec

by Chuck Lever

From: Chuck Lever <chuck.lever(a)oracle.com> Mike noted that when NFSD responds to an NFS_FILE_SYNC WRITE, it does not also persist file time stamps. To wit, Section 18.32.3 of RFC 8881 mandates: > The client specifies with the stable parameter the method of how > the data is to be processed by the server. If stable is > FILE_SYNC4, the server MUST commit the data written plus all file > system metadata to stable storage before returning results. This > corresponds to the NFSv2 protocol semantics. Any other behavior > constitutes a protocol violation. If stable is DATA_SYNC4, then > the server MUST commit all of the data to stable storage and > enough of the metadata to retrieve the data before returning. Commit 3f3503adb332 ("NFSD: Use vfs_iocb_iter_write()") replaced: - flags |= RWF_SYNC; with: + kiocb.ki_flags |= IOCB_DSYNC; which appears to be correct given: if (flags & RWF_SYNC) kiocb_flags |= IOCB_DSYNC; in kiocb_set_rw_flags(). However the author of that commit did not appreciate that the previous line in kiocb_set_rw_flags() results in IOCB_SYNC also being set: kiocb_flags |= (__force int) (flags & RWF_SUPPORTED); RWF_SUPPORTED contains RWF_SYNC, and RWF_SYNC is the same bit as IOCB_SYNC. Reviewers at the time did not catch the omission. Reported-by: Mike Snitzer <snitzer(a)kernel.org> Closes: https://lore.kernel.org/linux-nfs/20251018005431.3403-1-cel@kernel.org/T/#t Fixes: 3f3503adb332 ("NFSD: Use vfs_iocb_iter_write()") Cc: stable(a)vger.kernel.org Reviewed-by: Jeff Layton <jlayton(a)kernel.org> Reviewed-by: NeilBrown <neil(a)brown.name> Reviewed-by: Christoph Hellwig <hch(a)lst.de> Signed-off-by: Chuck Lever <chuck.lever(a)oracle.com> --- fs/nfsd/vfs.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index f537a7b4ee01..5333d49910d9 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1314,8 +1314,18 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, stable = NFS_UNSTABLE; init_sync_kiocb(&kiocb, file); kiocb.ki_pos = offset; - if (stable && !fhp->fh_use_wgather) - kiocb.ki_flags |= IOCB_DSYNC; + if (likely(!fhp->fh_use_wgather)) { + switch (stable) { + case NFS_FILE_SYNC: + /* persist data and timestamps */ + kiocb.ki_flags |= IOCB_DSYNC | IOCB_SYNC; + break; + case NFS_DATA_SYNC: + /* persist data only */ + kiocb.ki_flags |= IOCB_DSYNC; + break; + } + } nvecs = xdr_buf_to_bvec(rqstp->rq_bvec, rqstp->rq_maxpages, payload); iov_iter_bvec(&iter, ITER_SOURCE, rqstp->rq_bvec, nvecs, *cnt); -- 2.51.0

2 days, 7 hours

1
0
0 0

[PATCH v2] usb: mtu3: fix possible NULL pointer dereference in ep0_rx_state()

by Pavel Zhigulin

The function 'ep0_rx_state()' accessed 'mreq->request' before verifying that mreq was valid. If 'next_ep0_request()' returned NULL, this could lead to a NULL pointer dereference. The return value of 'next_ep0_request()' is checked in every other code path except here. It appears that the intended 'if (mreq)' check was mistakenly written as 'if (req)', since the req pointer cannot be NULL when mreq is not NULL. Initialize 'mreq' and 'req' to NULL by default, and switch 'req' NULL-checking to 'mreq' non-NULL check to prevent invalid memory access. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: df2069acb005 ("usb: Add MediaTek USB3 DRD driver") Signed-off-by: Pavel Zhigulin <Pavel.Zhigulin(a)kaspersky.com> --- v2: Add <stable(a)vger.kernel.org> to CC list v1: https://lore.kernel.org/all/20251027193152.3906497-1-Pavel.Zhigulin@kaspers… drivers/usb/mtu3/mtu3_gadget_ep0.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/usb/mtu3/mtu3_gadget_ep0.c b/drivers/usb/mtu3/mtu3_gadget_ep0.c index e4fd1bb14a55..ee7466ca4d99 100644 --- a/drivers/usb/mtu3/mtu3_gadget_ep0.c +++ b/drivers/usb/mtu3/mtu3_gadget_ep0.c @@ -508,8 +508,8 @@ static int handle_standard_request(struct mtu3 *mtu, /* receive an data packet (OUT) */ static void ep0_rx_state(struct mtu3 *mtu) { - struct mtu3_request *mreq; - struct usb_request *req; + struct mtu3_request *mreq = NULL; + struct usb_request *req = NULL; void __iomem *mbase = mtu->mac_base; u32 maxp; u32 csr; @@ -519,10 +519,11 @@ static void ep0_rx_state(struct mtu3 *mtu) csr = mtu3_readl(mbase, U3D_EP0CSR) & EP0_W1C_BITS; mreq = next_ep0_request(mtu); - req = &mreq->request; /* read packet and ack; or stall because of gadget driver bug */ - if (req) { + if (mreq) { + req = &mreq->request; + void *buf = req->buf + req->actual; unsigned int len = req->length - req->actual; -- 2.43.0

2 days, 8 hours

2
1
0 0

[PATCH stable 6.1.y] nfsd: use __clamp in nfsd4_get_drc_mem()

by NeilBrown

From: NeilBrown <neil(a)brown.name> A recent change to clamp_t() in 6.1.y caused fs/nfsd/nfs4state.c to fail to compile with gcc-9. The code was written with the assumption that when "max < min", clamp(val, min, max) would return max. This assumption is not documented as an API promise and the change cause a compile failure if it could be statically determined that "max < min". The relevant code was no longer present upstream when the clamp() change landed there, so there is no upstream change to backport. As there is no clear case that the code is functioning incorrectly, the patch aims to restore the behaviour to exactly that before the clamp change, and to match what compilers other than gcc-9 produce. clamp_t(type,v,min,max) is replaced with __clamp((type)v, (type)min, (type)max) Some of those type casts are unnecessary but they are included to make the code obviously correct. (__clamp() is the same as clamp(), but without the static API usage test). Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220745#c0 Fixes: 1519fbc8832b ("minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()") Signed-off-by: NeilBrown <neil(a)brown.name> --- fs/nfsd/nfs4state.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 08bfc2b29b65..d485a140d36d 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -1822,8 +1822,9 @@ static u32 nfsd4_get_drc_mem(struct nfsd4_channel_attrs *ca, struct nfsd_net *nn */ scale_factor = max_t(unsigned int, 8, nn->nfsd_serv->sv_nrthreads); - avail = clamp_t(unsigned long, avail, slotsize, - total_avail/scale_factor); + avail = __clamp((unsigned long)avail, + (unsigned long)slotsize, + (unsigned long)(total_avail/scale_factor)); num = min_t(int, num, avail / slotsize); num = max_t(int, num, 1); nfsd_drc_mem_used += num * slotsize; -- 2.50.0.107.gf914562f5916.dirty

2 days, 8 hours

4
5
0 0

[PATCH v2] EDAC/altera: Use INTTEST register for Ethernet and USB SBE injection

by niravkumarlaxmidas.rabara＠altera.com

From: Niravkumar L Rabara <niravkumarlaxmidas.rabara(a)altera.com> The current single-bit error injection mechanism flips bits directly in ECC RAM by performing write and read operations. When the ECC RAM is actively used by the Ethernet or USB controller, this approach sometimes trigger a false double-bit error. Switch both Ethernet and USB EDAC devices to use the INTTEST register (altr_edac_a10_device_inject_fops) for single-bit error injection, similar to the existing double-bit error injection method. Fixes: 064acbd4f4ab ("EDAC, altera: Add Stratix10 peripheral support") Cc: stable(a)vger.kernel.org Signed-off-by: Niravkumar L Rabara <niravkumarlaxmidas.rabara(a)altera.com> --- v2 changes: - Add missing Cc tag v1 link: https://lore.kernel.org/all/20251101051723.917688-1-niravkumarlaxmidas.raba… drivers/edac/altera_edac.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/edac/altera_edac.c b/drivers/edac/altera_edac.c index 103b2c2eba2a..5c5d4585d8ae 100644 --- a/drivers/edac/altera_edac.c +++ b/drivers/edac/altera_edac.c @@ -1357,7 +1357,7 @@ static const struct edac_device_prv_data a10_enetecc_data = { .ue_set_mask = ALTR_A10_ECC_TDERRA, .set_err_ofst = ALTR_A10_ECC_INTTEST_OFST, .ecc_irq_handler = altr_edac_a10_ecc_irq, - .inject_fops = &altr_edac_a10_device_inject2_fops, + .inject_fops = &altr_edac_a10_device_inject_fops, }; #endif /* CONFIG_EDAC_ALTERA_ETHERNET */ @@ -1447,7 +1447,7 @@ static const struct edac_device_prv_data a10_usbecc_data = { .ue_set_mask = ALTR_A10_ECC_TDERRA, .set_err_ofst = ALTR_A10_ECC_INTTEST_OFST, .ecc_irq_handler = altr_edac_a10_ecc_irq, - .inject_fops = &altr_edac_a10_device_inject2_fops, + .inject_fops = &altr_edac_a10_device_inject_fops, }; #endif /* CONFIG_EDAC_ALTERA_USB */ -- 2.25.1

2 days, 8 hours

3
2
0 0

[PATCH v2] EDAC/altera: Handle OCRAM ECC enable after warm reset

by niravkumarlaxmidas.rabara＠altera.com

From: Niravkumar L Rabara <niravkumarlaxmidas.rabara(a)altera.com> The OCRAM ECC is always enabled either by the BootROM or by the Secure Device Manager (SDM) during a power-on reset on SoCFPGA. However, during a warm reset, the OCRAM content is retained to preserve data, while the control and status registers are reset to their default values. As a result, ECC must be explicitly re-enabled after a warm reset. Fixes: 17e47dc6db4f ("EDAC/altera: Add Stratix10 OCRAM ECC support") Cc: stable(a)vger.kernel.org Signed-off-by: Niravkumar L Rabara <niravkumarlaxmidas.rabara(a)altera.com> Acked-by: Dinh Nguyen <dinguyen(a)kernel.org> --- v2 changes: - Add Fixes and Cc tags - Retains Acked-by from v1 patch v1 link: https://lore.kernel.org/all/20251103140920.1060643-1-niravkumarlaxmidas.rab… drivers/edac/altera_edac.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/edac/altera_edac.c b/drivers/edac/altera_edac.c index 103b2c2eba2a..a776d61027f2 100644 --- a/drivers/edac/altera_edac.c +++ b/drivers/edac/altera_edac.c @@ -1184,10 +1184,22 @@ altr_check_ocram_deps_init(struct altr_edac_device_dev *device) if (ret) return ret; - /* Verify OCRAM has been initialized */ + /* + * Verify that OCRAM has been initialized. + * During a warm reset, OCRAM contents are retained, but the control + * and status registers are reset to their default values. Therefore, + * ECC must be explicitly re-enabled in the control register. + * Error condition: if INITCOMPLETEA is clear and ECC_EN is already set. + */ if (!ecc_test_bits(ALTR_A10_ECC_INITCOMPLETEA, - (base + ALTR_A10_ECC_INITSTAT_OFST))) - return -ENODEV; + (base + ALTR_A10_ECC_INITSTAT_OFST))) { + if (!ecc_test_bits(ALTR_A10_ECC_EN, + (base + ALTR_A10_ECC_CTRL_OFST))) + ecc_set_bits(ALTR_A10_ECC_EN, + (base + ALTR_A10_ECC_CTRL_OFST)); + else + return -ENODEV; + } /* Enable IRQ on Single Bit Error */ writel(ALTR_A10_ECC_SERRINTEN, (base + ALTR_A10_ECC_ERRINTENS_OFST)); -- 2.25.1

2 days, 8 hours

2
1
0 0

[PATCH 0/2] fuse: Fix missing fuse_copy_finish in dev_uring.c

by Bernd Schubert

Both argument copies in dev_uring.c miss fuse_copy_finish. Signed-off-by: Bernd Schubert <bschubert(a)ddn.com> --- Bernd Schubert (1): fuse: Fix whitespace for fuse_uring_args_to_ring() comment Cheng Ding (1): fuse: missing copy_finish in fuse-over-io-uring argument copies fs/fuse/dev.c | 2 +- fs/fuse/dev_uring.c | 18 ++++++++++++------ fs/fuse/fuse_dev_i.h | 1 + 3 files changed, 14 insertions(+), 7 deletions(-) --- base-commit: 6548d364a3e850326831799d7e3ea2d7bb97ba08 change-id: 20251021-io-uring-fixes-copy-finish-07ae602e2ab1 Best regards, -- Bernd Schubert <bschubert(a)ddn.com>

2 days, 8 hours

3
3
0 0

[PATCH v2] atm/fore200e: Fix possible data race in fore200e_open()

by Gui-Dong Han

Protect access to fore200e->available_cell_rate with rate_mtx lock to prevent potential data race. In this case, since the update depends on a prior read, a data race could lead to a wrong fore200e.available_cell_rate value. The field fore200e.available_cell_rate is generally protected by the lock fore200e.rate_mtx when accessed. In all other read and write cases, this field is consistently protected by the lock, except for this case and during initialization. This potential bug was detected by our experimental static analysis tool, which analyzes locking APIs and paired functions to identify data races and atomicity violations. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable(a)vger.kernel.org Signed-off-by: Gui-Dong Han <2045gemini(a)gmail.com> --- v2: * Added a description of the data race hazard in fore200e_open(), as suggested by Jakub Kicinski and Simon Horman. --- drivers/atm/fore200e.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/atm/fore200e.c b/drivers/atm/fore200e.c index 4fea1149e003..f62e38571440 100644 --- a/drivers/atm/fore200e.c +++ b/drivers/atm/fore200e.c @@ -1374,7 +1374,9 @@ fore200e_open(struct atm_vcc *vcc) vcc->dev_data = NULL; + mutex_lock(&fore200e->rate_mtx); fore200e->available_cell_rate += vcc->qos.txtp.max_pcr; + mutex_unlock(&fore200e->rate_mtx); kfree(fore200e_vcc); return -EINVAL; -- 2.25.1

2 days, 9 hours

3
4
0 0

[PATCH v2 0/2] Fix SSR unable to wake up bug

by Shuai Zhang

This patch series fixes delayed hw_error handling during SSR. Patch 1 adds a wakeup to ensure hw_error is processed promptly after coredump collection. Patch 2 corrects the timeout unit from jiffies to ms. Changes v2: - Split timeout conversion into a separate patch. - Clarified commit messages and added test case description. - Link to v1 https://lore.kernel.org/all/20251104112601.2670019-1-quic_shuaz@quicinc.com/ Shuai Zhang (2): Bluetooth: qca: Fix delayed hw_error handling due to missing wakeup during SSR Bluetooth: hci_qca: Convert timeout from jiffies to ms drivers/bluetooth/hci_qca.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) -- 2.34.1

2 days, 9 hours

3
5
0 0

[tip: sched/core] sched/eevdf: Fix min_vruntime vs avg_vruntime

by tip-bot2 for Peter Zijlstra

The following commit has been merged into the sched/core branch of tip: Commit-ID: 79f3f9bedd149ea438aaeb0fb6a083637affe205 Gitweb: https://git.kernel.org/tip/79f3f9bedd149ea438aaeb0fb6a083637affe205 Author: Peter Zijlstra <peterz(a)infradead.org> AuthorDate: Wed, 02 Apr 2025 20:07:34 +02:00 Committer: Peter Zijlstra <peterz(a)infradead.org> CommitterDate: Tue, 11 Nov 2025 12:33:38 +01:00 sched/eevdf: Fix min_vruntime vs avg_vruntime Basically, from the constraint that the sum of lag is zero, you can infer that the 0-lag point is the weighted average of the individual vruntime, which is what we're trying to compute: \Sum w_i * v_i avg = -------------- \Sum w_i Now, since vruntime takes the whole u64 (worse, it wraps), this multiplication term in the numerator is not something we can compute; instead we do the min_vruntime (v0 henceforth) thing like: v_i = (v_i - v0) + v0 This does two things: - it keeps the key: (v_i - v0) 'small'; - it creates a relative 0-point in the modular space. If you do that subtitution and work it all out, you end up with: \Sum w_i * (v_i - v0) avg = --------------------- + v0 \Sum w_i Since you cannot very well track a ratio like that (and not suffer terrible numerical problems) we simpy track the numerator and denominator individually and only perform the division when strictly needed. Notably, the numerator lives in cfs_rq->avg_vruntime and the denominator lives in cfs_rq->avg_load. The one extra 'funny' is that these numbers track the entities in the tree, and current is typically outside of the tree, so avg_vruntime() adds current when needed before doing the division. (vruntime_eligible() elides the division by cross-wise multiplication) Anyway, as mentioned above, we currently use the CFS era min_vruntime for this purpose. However, this thing can only move forward, while the above avg can in fact move backward (when a non-eligible task leaves, the average becomes smaller), this can cause trouble when through happenstance (or construction) these values drift far enough apart to wreck the game. Replace cfs_rq::min_vruntime with cfs_rq::zero_vruntime which is kept near/at avg_vruntime, following its motion. The down-side is that this requires computing the avg more often. Fixes: 147f3efaa241 ("sched/fair: Implement an EEVDF-like scheduling policy") Reported-by: Zicheng Qu <quzicheng(a)huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Link: https://patch.msgid.link/20251106111741.GC4068168@noisy.programming.kicks-a… Cc: stable(a)vger.kernel.org --- kernel/sched/debug.c | 8 +-- kernel/sched/fair.c | 114 +++++++++--------------------------------- kernel/sched/sched.h | 4 +- 3 files changed, 31 insertions(+), 95 deletions(-) diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 02e16b7..41caa22 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -796,7 +796,7 @@ static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu) void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) { - s64 left_vruntime = -1, min_vruntime, right_vruntime = -1, left_deadline = -1, spread; + s64 left_vruntime = -1, zero_vruntime, right_vruntime = -1, left_deadline = -1, spread; struct sched_entity *last, *first, *root; struct rq *rq = cpu_rq(cpu); unsigned long flags; @@ -819,15 +819,15 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) last = __pick_last_entity(cfs_rq); if (last) right_vruntime = last->vruntime; - min_vruntime = cfs_rq->min_vruntime; + zero_vruntime = cfs_rq->zero_vruntime; raw_spin_rq_unlock_irqrestore(rq, flags); SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "left_deadline", SPLIT_NS(left_deadline)); SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "left_vruntime", SPLIT_NS(left_vruntime)); - SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "min_vruntime", - SPLIT_NS(min_vruntime)); + SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "zero_vruntime", + SPLIT_NS(zero_vruntime)); SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "avg_vruntime", SPLIT_NS(avg_vruntime(cfs_rq))); SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "right_vruntime", diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 4a11a83..8d971d4 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -554,7 +554,7 @@ static inline bool entity_before(const struct sched_entity *a, static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se) { - return (s64)(se->vruntime - cfs_rq->min_vruntime); + return (s64)(se->vruntime - cfs_rq->zero_vruntime); } #define __node_2_se(node) \ @@ -606,13 +606,13 @@ static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se) * * Which we track using: * - * v0 := cfs_rq->min_vruntime + * v0 := cfs_rq->zero_vruntime * \Sum (v_i - v0) * w_i := cfs_rq->avg_vruntime * \Sum w_i := cfs_rq->avg_load * - * Since min_vruntime is a monotonic increasing variable that closely tracks - * the per-task service, these deltas: (v_i - v), will be in the order of the - * maximal (virtual) lag induced in the system due to quantisation. + * Since zero_vruntime closely tracks the per-task service, these + * deltas: (v_i - v), will be in the order of the maximal (virtual) lag + * induced in the system due to quantisation. * * Also, we use scale_load_down() to reduce the size. * @@ -671,7 +671,7 @@ u64 avg_vruntime(struct cfs_rq *cfs_rq) avg = div_s64(avg, load); } - return cfs_rq->min_vruntime + avg; + return cfs_rq->zero_vruntime + avg; } /* @@ -732,7 +732,7 @@ static int vruntime_eligible(struct cfs_rq *cfs_rq, u64 vruntime) load += weight; } - return avg >= (s64)(vruntime - cfs_rq->min_vruntime) * load; + return avg >= (s64)(vruntime - cfs_rq->zero_vruntime) * load; } int entity_eligible(struct cfs_rq *cfs_rq, struct sched_entity *se) @@ -740,42 +740,14 @@ int entity_eligible(struct cfs_rq *cfs_rq, struct sched_entity *se) return vruntime_eligible(cfs_rq, se->vruntime); } -static u64 __update_min_vruntime(struct cfs_rq *cfs_rq, u64 vruntime) +static void update_zero_vruntime(struct cfs_rq *cfs_rq) { - u64 min_vruntime = cfs_rq->min_vruntime; - /* - * open coded max_vruntime() to allow updating avg_vruntime - */ - s64 delta = (s64)(vruntime - min_vruntime); - if (delta > 0) { - avg_vruntime_update(cfs_rq, delta); - min_vruntime = vruntime; - } - return min_vruntime; -} + u64 vruntime = avg_vruntime(cfs_rq); + s64 delta = (s64)(vruntime - cfs_rq->zero_vruntime); -static void update_min_vruntime(struct cfs_rq *cfs_rq) -{ - struct sched_entity *se = __pick_root_entity(cfs_rq); - struct sched_entity *curr = cfs_rq->curr; - u64 vruntime = cfs_rq->min_vruntime; - - if (curr) { - if (curr->on_rq) - vruntime = curr->vruntime; - else - curr = NULL; - } + avg_vruntime_update(cfs_rq, delta); - if (se) { - if (!curr) - vruntime = se->min_vruntime; - else - vruntime = min_vruntime(vruntime, se->min_vruntime); - } - - /* ensure we never gain time by being placed backwards. */ - cfs_rq->min_vruntime = __update_min_vruntime(cfs_rq, vruntime); + cfs_rq->zero_vruntime = vruntime; } static inline u64 cfs_rq_min_slice(struct cfs_rq *cfs_rq) @@ -848,6 +820,7 @@ RB_DECLARE_CALLBACKS(static, min_vruntime_cb, struct sched_entity, static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) { avg_vruntime_add(cfs_rq, se); + update_zero_vruntime(cfs_rq); se->min_vruntime = se->vruntime; se->min_slice = se->slice; rb_add_augmented_cached(&se->run_node, &cfs_rq->tasks_timeline, @@ -859,6 +832,7 @@ static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) rb_erase_augmented_cached(&se->run_node, &cfs_rq->tasks_timeline, &min_vruntime_cb); avg_vruntime_sub(cfs_rq, se); + update_zero_vruntime(cfs_rq); } struct sched_entity *__pick_root_entity(struct cfs_rq *cfs_rq) @@ -1226,7 +1200,6 @@ static void update_curr(struct cfs_rq *cfs_rq) curr->vruntime += calc_delta_fair(delta_exec, curr); resched = update_deadline(cfs_rq, curr); - update_min_vruntime(cfs_rq); if (entity_is_task(curr)) { /* @@ -3808,15 +3781,6 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, if (!curr) __enqueue_entity(cfs_rq, se); cfs_rq->nr_queued++; - - /* - * The entity's vruntime has been adjusted, so let's check - * whether the rq-wide min_vruntime needs updated too. Since - * the calculations above require stable min_vruntime rather - * than up-to-date one, we do the update at the end of the - * reweight process. - */ - update_min_vruntime(cfs_rq); } } @@ -5429,15 +5393,6 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) update_cfs_group(se); - /* - * Now advance min_vruntime if @se was the entity holding it back, - * except when: DEQUEUE_SAVE && !DEQUEUE_MOVE, in this case we'll be - * put back on, and if we advance min_vruntime, we'll be placed back - * further than we started -- i.e. we'll be penalized. - */ - if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) != DEQUEUE_SAVE) - update_min_vruntime(cfs_rq); - if (flags & DEQUEUE_DELAYED) finish_delayed_dequeue_entity(se); @@ -9015,7 +8970,6 @@ static void yield_task_fair(struct rq *rq) if (entity_eligible(cfs_rq, se)) { se->vruntime = se->deadline; se->deadline += calc_delta_fair(se->slice, se); - update_min_vruntime(cfs_rq); } } @@ -13078,23 +13032,6 @@ static inline void task_tick_core(struct rq *rq, struct task_struct *curr) * Which shows that S and s_i transform alike (which makes perfect sense * given that S is basically the (weighted) average of s_i). * - * Then: - * - * x -> s_min := min{s_i} (8) - * - * to obtain: - * - * \Sum_i w_i (s_i - s_min) - * S = s_min + ------------------------ (9) - * \Sum_i w_i - * - * Which already looks familiar, and is the basis for our current - * approximation: - * - * S ~= s_min (10) - * - * Now, obviously, (10) is absolute crap :-), but it sorta works. - * * So the thing to remember is that the above is strictly UP. It is * possible to generalize to multiple runqueues -- however it gets really * yuck when you have to add affinity support, as illustrated by our very @@ -13116,23 +13053,23 @@ static inline void task_tick_core(struct rq *rq, struct task_struct *curr) * Let, for our runqueue 'k': * * T_k = \Sum_i w_i s_i - * W_k = \Sum_i w_i ; for all i of k (11) + * W_k = \Sum_i w_i ; for all i of k (8) * * Then we can write (6) like: * * T_k - * S_k = --- (12) + * S_k = --- (9) * W_k * * From which immediately follows that: * * T_k + T_l - * S_k+l = --------- (13) + * S_k+l = --------- (10) * W_k + W_l * * On which we can define a combined lag: * - * lag_k+l(i) := S_k+l - s_i (14) + * lag_k+l(i) := S_k+l - s_i (11) * * And that gives us the tools to compare tasks across a combined runqueue. * @@ -13143,7 +13080,7 @@ static inline void task_tick_core(struct rq *rq, struct task_struct *curr) * using (7); this only requires storing single 'time'-stamps. * * b) when comparing tasks between 2 runqueues of which one is forced-idle, - * compare the combined lag, per (14). + * compare the combined lag, per (11). * * Now, of course cgroups (I so hate them) make this more interesting in * that a) seems to suggest we need to iterate all cgroup on a CPU at such @@ -13191,12 +13128,11 @@ static inline void task_tick_core(struct rq *rq, struct task_struct *curr) * every tick. This limits the observed divergence due to the work * conservancy. * - * On top of that, we can improve upon things by moving away from our - * horrible (10) hack and moving to (9) and employing (13) here. + * On top of that, we can improve upon things by employing (10) here. */ /* - * se_fi_update - Update the cfs_rq->min_vruntime_fi in a CFS hierarchy if needed. + * se_fi_update - Update the cfs_rq->zero_vruntime_fi in a CFS hierarchy if needed. */ static void se_fi_update(const struct sched_entity *se, unsigned int fi_seq, bool forceidle) @@ -13210,7 +13146,7 @@ static void se_fi_update(const struct sched_entity *se, unsigned int fi_seq, cfs_rq->forceidle_seq = fi_seq; } - cfs_rq->min_vruntime_fi = cfs_rq->min_vruntime; + cfs_rq->zero_vruntime_fi = cfs_rq->zero_vruntime; } } @@ -13263,11 +13199,11 @@ bool cfs_prio_less(const struct task_struct *a, const struct task_struct *b, /* * Find delta after normalizing se's vruntime with its cfs_rq's - * min_vruntime_fi, which would have been updated in prior calls + * zero_vruntime_fi, which would have been updated in prior calls * to se_fi_update(). */ delta = (s64)(sea->vruntime - seb->vruntime) + - (s64)(cfs_rqb->min_vruntime_fi - cfs_rqa->min_vruntime_fi); + (s64)(cfs_rqb->zero_vruntime_fi - cfs_rqa->zero_vruntime_fi); return delta > 0; } @@ -13513,7 +13449,7 @@ static void set_next_task_fair(struct rq *rq, struct task_struct *p, bool first) void init_cfs_rq(struct cfs_rq *cfs_rq) { cfs_rq->tasks_timeline = RB_ROOT_CACHED; - cfs_rq->min_vruntime = (u64)(-(1LL << 20)); + cfs_rq->zero_vruntime = (u64)(-(1LL << 20)); raw_spin_lock_init(&cfs_rq->removed.lock); } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 82e74e8..5a3cf81 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -681,10 +681,10 @@ struct cfs_rq { s64 avg_vruntime; u64 avg_load; - u64 min_vruntime; + u64 zero_vruntime; #ifdef CONFIG_SCHED_CORE unsigned int forceidle_seq; - u64 min_vruntime_fi; + u64 zero_vruntime_fi; #endif struct rb_root_cached tasks_timeline;

2 days, 10 hours

1
0
0 0

2025

2024

2023

2022

2021

2020

2019

2018

2017

Linux-stable-mirror