From 36a6e2335c45212f2609269bcee3004908ac6bcb Mon Sep 17 00:00:00 2001 From: Ryan Moeller Date: Thu, 9 Apr 2020 18:39:48 -0400 Subject: [PATCH] Don't ignore zfs_arc_max below allmem/32 Set arc_c_min before arc_c_max so that when zfs_arc_min is set lower than the default allmem/32 zfs_arc_max can also be set lower. Add warning messages when tunables are being ignored. Reviewed-by: Brian Behlendorf Signed-off-by: Ryan Moeller Closes #10157 Closes #10158 --- include/sys/arc_impl.h | 2 +- module/os/linux/zfs/arc_os.c | 4 ++-- module/zfs/arc.c | 40 +++++++++++++++++++++++++----------- 3 files changed, 31 insertions(+), 15 deletions(-) diff --git a/include/sys/arc_impl.h b/include/sys/arc_impl.h index d4167945f4..2468a4aac7 100644 --- a/include/sys/arc_impl.h +++ b/include/sys/arc_impl.h @@ -612,7 +612,7 @@ extern void arc_prune_async(int64_t); extern int arc_memory_throttle(spa_t *spa, uint64_t reserve, uint64_t txg); extern uint64_t arc_free_memory(void); extern int64_t arc_available_memory(void); -extern void arc_tuning_update(void); +extern void arc_tuning_update(boolean_t); extern int param_set_arc_long(ZFS_MODULE_PARAM_ARGS); extern int param_set_arc_int(ZFS_MODULE_PARAM_ARGS); diff --git a/module/os/linux/zfs/arc_os.c b/module/os/linux/zfs/arc_os.c index bff0f05179..e34d4ae080 100644 --- a/module/os/linux/zfs/arc_os.c +++ b/module/os/linux/zfs/arc_os.c @@ -377,7 +377,7 @@ param_set_arc_long(const char *buf, zfs_kernel_param_t *kp) if (error < 0) return (SET_ERROR(error)); - arc_tuning_update(); + arc_tuning_update(B_TRUE); return (0); } @@ -391,7 +391,7 @@ param_set_arc_int(const char *buf, zfs_kernel_param_t *kp) if (error < 0) return (SET_ERROR(error)); - arc_tuning_update(); + arc_tuning_update(B_TRUE); return (0); } diff --git a/module/zfs/arc.c b/module/zfs/arc.c index 9c5ee9829c..b5d17431ce 100644 --- a/module/zfs/arc.c +++ b/module/zfs/arc.c @@ -4558,7 +4558,7 @@ arc_adjust_cb_check(void *arg, zthr_t *zthr) * their actual internal variable counterparts. Without this, * changing those module params at runtime would have no effect. */ - arc_tuning_update(); + arc_tuning_update(B_FALSE); /* * This is necessary in order to keep the kstat information @@ -6900,6 +6900,14 @@ arc_state_multilist_index_func(multilist_t *ml, void *obj) multilist_get_num_sublists(ml)); } +#define WARN_IF_TUNING_IGNORED(tuning, value, do_warn) do { \ + if ((do_warn) && (tuning) && ((tuning) != (value))) { \ + cmn_err(CE_WARN, \ + "ignoring tunable %s (using %llu instead)", \ + (#tuning), (value)); \ + } \ +} while (0) + /* * Called during module initialization and periodically thereafter to * apply reasonable changes to the exposed performance tunings. Can also be @@ -6908,11 +6916,20 @@ arc_state_multilist_index_func(multilist_t *ml, void *obj) * values will be applied. */ void -arc_tuning_update(void) +arc_tuning_update(boolean_t verbose) { uint64_t allmem = arc_all_memory(); unsigned long limit; + /* Valid range: 32M - */ + if ((zfs_arc_min) && (zfs_arc_min != arc_c_min) && + (zfs_arc_min >= 2ULL << SPA_MAXBLOCKSHIFT) && + (zfs_arc_min <= arc_c_max)) { + arc_c_min = zfs_arc_min; + arc_c = MAX(arc_c, arc_c_min); + } + WARN_IF_TUNING_IGNORED(zfs_arc_min, arc_c_min, verbose); + /* Valid range: 64M - */ if ((zfs_arc_max) && (zfs_arc_max != arc_c_max) && (zfs_arc_max >= 64 << 20) && (zfs_arc_max < allmem) && @@ -6925,14 +6942,7 @@ arc_tuning_update(void) if (arc_dnode_size_limit > arc_meta_limit) arc_dnode_size_limit = arc_meta_limit; } - - /* Valid range: 32M - */ - if ((zfs_arc_min) && (zfs_arc_min != arc_c_min) && - (zfs_arc_min >= 2ULL << SPA_MAXBLOCKSHIFT) && - (zfs_arc_min <= arc_c_max)) { - arc_c_min = zfs_arc_min; - arc_c = MAX(arc_c, arc_c_min); - } + WARN_IF_TUNING_IGNORED(zfs_arc_max, arc_c_max, verbose); /* Valid range: 16M - */ if ((zfs_arc_meta_min) && (zfs_arc_meta_min != arc_meta_min) && @@ -6944,6 +6954,7 @@ arc_tuning_update(void) if (arc_dnode_size_limit < arc_meta_min) arc_dnode_size_limit = arc_meta_min; } + WARN_IF_TUNING_IGNORED(zfs_arc_meta_min, arc_meta_min, verbose); /* Valid range: - */ limit = zfs_arc_meta_limit ? zfs_arc_meta_limit : @@ -6952,6 +6963,7 @@ arc_tuning_update(void) (limit >= arc_meta_min) && (limit <= arc_c_max)) arc_meta_limit = limit; + WARN_IF_TUNING_IGNORED(zfs_arc_meta_limit, arc_meta_limit, verbose); /* Valid range: - */ limit = zfs_arc_dnode_limit ? zfs_arc_dnode_limit : @@ -6960,6 +6972,8 @@ arc_tuning_update(void) (limit >= arc_meta_min) && (limit <= arc_meta_limit)) arc_dnode_size_limit = limit; + WARN_IF_TUNING_IGNORED(zfs_arc_dnode_limit, arc_dnode_size_limit, + verbose); /* Valid range: 1 - N */ if (zfs_arc_grow_retry) @@ -6989,11 +7003,13 @@ arc_tuning_update(void) if ((zfs_arc_lotsfree_percent >= 0) && (zfs_arc_lotsfree_percent <= 100)) arc_lotsfree_percent = zfs_arc_lotsfree_percent; + WARN_IF_TUNING_IGNORED(zfs_arc_lotsfree_percent, arc_lotsfree_percent, + verbose); /* Valid range: 0 - */ if ((zfs_arc_sys_free) && (zfs_arc_sys_free != arc_sys_free)) arc_sys_free = MIN(MAX(zfs_arc_sys_free, 0), allmem); - + WARN_IF_TUNING_IGNORED(zfs_arc_sys_free, arc_sys_free, verbose); } static void @@ -7183,7 +7199,7 @@ arc_init(void) arc_dnode_size_limit = (percent * arc_meta_limit) / 100; /* Apply user specified tunings */ - arc_tuning_update(); + arc_tuning_update(B_TRUE); /* if kmem_flags are set, lets try to use less memory */ if (kmem_debugging())