user/sven/linux.git/kernel/rcu/refscale.c, branch v6.16.2

refscale: Check that nreaders and loops multiplication doesn't overflow

2025-08-15T14:38:42Z

[ Upstream commit 005b6187705bc9723518ce19c5cb911fc1f7ef07 ] The nreaders and loops variables are exposed as module parameters, which, in certain combinations, can lead to multiplication overflow. Besides, loops parameter is defined as long, while through the code is used as int, which can cause truncation on 64-bit kernels and possible zeroes where they shouldn't appear. Since code uses result of multiplication as int anyway, it only makes sense to replace loops with int. Multiplication overflow check is also added due to possible multiplication between two very big numbers. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: 653ed64b01dc ("refperf: Add a test to measure performance of read-side synchronization") Signed-off-by: Artem Sadovnikov Signed-off-by: Neeraj Upadhyay (AMD) Signed-off-by: Sasha Levin

refscale: Add srcu_read_lock_fast() support using "srcu-fast"

2025-02-05T15:12:05Z

This commit creates a new srcu-fast option for the refscale.scale_type module parameter that selects srcu_read_lock_fast() and srcu_read_unlock_fast(). Signed-off-by: Paul E. McKenney Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Kent Overstreet Cc: Signed-off-by: Boqun Feng

refscale: Add test for sched_clock()

2024-12-14T15:16:33Z

This commit adds a "sched-clock" test for the sched_clock() function. Signed-off-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker Signed-off-by: Uladzislau Rezki (Sony)

Merge branches 'rcu/fixes', 'rcu/nocb', 'rcu/torture', 'rcu/stall' and 'rcu/srcu' into rcu/dev

2024-11-15T21:38:53Z

rcuscale: Add guest_os_delay module parameter

2024-11-12T22:05:05Z

This commit adds a guest_os_delay module parameter that extends warm-up and cool-down the specified number of seconds before and after the series of test runs. This allows the data-collection intervals from any given rcuscale guest OSes to line up with active periods in the other rcuscale guest OSes, and also allows the thermal warm-up period required to obtain consistent results from one test to the next. Signed-off-by: Paul E. McKenney Reviewed-by: Neeraj Upadhyay Signed-off-by: Frederic Weisbecker

refscale: Correct affinity check

2024-11-12T22:04:50Z

The current affinity check works fine until there are more reader processes than CPUs, at which point the affinity check is looking for non-existent CPUs. This commit therefore applies the same modulus to the check as is present in the set_cpus_allowed_ptr() call. Signed-off-by: Paul E. McKenney Reviewed-by: Neeraj Upadhyay Signed-off-by: Frederic Weisbecker

refscale: Add srcu_read_lock_lite() support using "srcu-lite"

2024-11-12T14:45:02Z

This commit creates a new srcu-lite option for the refscale.scale_type module parameter that selects srcu_read_lock_lite() and srcu_read_unlock_lite(). [ paulmck: Apply Dan Carpenter feedback. ] Signed-off-by: Paul E. McKenney Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Kent Overstreet Cc: Reviewed-by: Neeraj Upadhyay Signed-off-by: Frederic Weisbecker

refscale: Constify struct ref_scale_ops

2024-08-14T18:44:48Z

'struct ref_scale_ops' are not modified in these drivers. Constifying this structure moves some data to a read-only section, so increase overall security. On a x86_64, with allmodconfig: Before: ====== text data bss dec hex filename 34231 4167 736 39134 98de kernel/rcu/refscale.o After: ===== text data bss dec hex filename 35175 3239 736 39150 98ee kernel/rcu/refscale.o Signed-off-by: Christophe JAILLET Tested-by: "Paul E. McKenney" Signed-off-by: Neeraj Upadhyay

refscale: Optimize process_durations()

2024-08-14T11:36:01Z

process_durations() is not a hot path, but there is no good reason to iterate over and over the data already in 'buf'. Using a seq_buf saves some useless strcat() and the need of a temp buffer. Data is written directly at the correct place. Signed-off-by: Christophe JAILLET Tested-by: "Paul E. McKenney" Reviewed-by: Davidlohr Bueso Signed-off-by: Neeraj Upadhyay

rcutorture: Add missing MODULE_DESCRIPTION() macros

2024-06-06T18:44:42Z

Fix the following 'make W=1' warnings: WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/rcu/rcutorture.o WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/rcu/rcuscale.o WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/rcu/refscale.o Signed-off-by: Jeff Johnson Signed-off-by: Paul E. McKenney