diff options
| -rw-r--r-- | include/sys/kmem.h | 3 | ||||
| -rw-r--r-- | module/spl/spl-kmem.c | 35 | ||||
| -rw-r--r-- | module/spl/spl-proc.c | 9 |
3 files changed, 34 insertions, 13 deletions
diff --git a/include/sys/kmem.h b/include/sys/kmem.h index e71a443a0..b0f4208bd 100644 --- a/include/sys/kmem.h +++ b/include/sys/kmem.h @@ -340,6 +340,7 @@ enum { KMC_BIT_VMEM = 6, /* Use vmem cache */ KMC_BIT_OFFSLAB = 7, /* Objects not on slab */ KMC_BIT_NOEMERGENCY = 8, /* Disable emergency objects */ + KMC_BIT_DEADLOCKED = 14, /* Deadlock detected */ KMC_BIT_GROWING = 15, /* Growing in progress */ KMC_BIT_REAPING = 16, /* Reaping in progress */ KMC_BIT_DESTROY = 17, /* Destroy in progress */ @@ -366,6 +367,7 @@ typedef enum kmem_cbrc { #define KMC_VMEM (1 << KMC_BIT_VMEM) #define KMC_OFFSLAB (1 << KMC_BIT_OFFSLAB) #define KMC_NOEMERGENCY (1 << KMC_BIT_NOEMERGENCY) +#define KMC_DEADLOCKED (1 << KMC_BIT_DEADLOCKED) #define KMC_GROWING (1 << KMC_BIT_GROWING) #define KMC_REAPING (1 << KMC_BIT_REAPING) #define KMC_DESTROY (1 << KMC_BIT_DESTROY) @@ -473,6 +475,7 @@ typedef struct spl_kmem_cache { uint64_t skc_obj_total; /* Obj total current */ uint64_t skc_obj_alloc; /* Obj alloc current */ uint64_t skc_obj_max; /* Obj max historic */ + uint64_t skc_obj_deadlock; /* Obj emergency deadlocks */ uint64_t skc_obj_emergency; /* Obj emergency current */ uint64_t skc_obj_emergency_max; /* Obj emergency max */ } spl_kmem_cache_t; diff --git a/module/spl/spl-kmem.c b/module/spl/spl-kmem.c index eca809c47..045075cc0 100644 --- a/module/spl/spl-kmem.c +++ b/module/spl/spl-kmem.c @@ -1495,6 +1495,7 @@ spl_kmem_cache_create(char *name, size_t size, size_t align, skc->skc_obj_total = 0; skc->skc_obj_alloc = 0; skc->skc_obj_max = 0; + skc->skc_obj_deadlock = 0; skc->skc_obj_emergency = 0; skc->skc_obj_emergency_max = 0; @@ -1662,6 +1663,7 @@ spl_cache_grow_work(void *data) atomic_dec(&skc->skc_ref); clear_bit(KMC_BIT_GROWING, &skc->skc_flags); + clear_bit(KMC_BIT_DEADLOCKED, &skc->skc_flags); wake_up_all(&skc->skc_waitq); spin_unlock(&skc->skc_lock); @@ -1683,7 +1685,7 @@ spl_cache_grow_wait(spl_kmem_cache_t *skc) static int spl_cache_grow(spl_kmem_cache_t *skc, int flags, void **obj) { - int remaining, rc = 0; + int remaining, rc; SENTRY; ASSERT(skc->skc_magic == SKC_MAGIC); @@ -1722,17 +1724,30 @@ spl_cache_grow(spl_kmem_cache_t *skc, int flags, void **obj) } /* - * Allow a single timer tick before falling back to synchronously - * allocating the minimum about of memory required by the caller. + * The goal here is to only detect the rare case where a virtual slab + * allocation has deadlocked. We must be careful to minimize the use + * of emergency objects which are more expensive to track. Therefore, + * we set a very long timeout for the asynchronous allocation and if + * the timeout is reached the cache is flagged as deadlocked. From + * this point only new emergency objects will be allocated until the + * asynchronous allocation completes and clears the deadlocked flag. */ - remaining = wait_event_timeout(skc->skc_waitq, - spl_cache_grow_wait(skc), 1); + if (test_bit(KMC_BIT_DEADLOCKED, &skc->skc_flags)) { + rc = spl_emergency_alloc(skc, flags, obj); + } else { + remaining = wait_event_timeout(skc->skc_waitq, + spl_cache_grow_wait(skc), HZ); - if (remaining == 0) { - if (test_bit(KMC_BIT_NOEMERGENCY, &skc->skc_flags)) - rc = -ENOMEM; - else - rc = spl_emergency_alloc(skc, flags, obj); + if (!remaining && test_bit(KMC_BIT_VMEM, &skc->skc_flags)) { + spin_lock(&skc->skc_lock); + if (test_bit(KMC_BIT_GROWING, &skc->skc_flags)) { + set_bit(KMC_BIT_DEADLOCKED, &skc->skc_flags); + skc->skc_obj_deadlock++; + } + spin_unlock(&skc->skc_lock); + } + + rc = -ENOMEM; } SRETURN(rc); diff --git a/module/spl/spl-proc.c b/module/spl/spl-proc.c index 11a2d1068..152abff7f 100644 --- a/module/spl/spl-proc.c +++ b/module/spl/spl-proc.c @@ -625,12 +625,14 @@ slab_seq_show_headers(struct seq_file *f) "--------------------- cache ----------" "--------------------------------------------- " "----- slab ------ " - "---- object -----------------\n"); + "---- object ----- " + "--- emergency ---\n"); seq_printf(f, "name " " flags size alloc slabsize objsize " "total alloc max " - "total alloc max emerg max\n"); + "total alloc max " + "dlock alloc max\n"); } static int @@ -643,7 +645,7 @@ slab_seq_show(struct seq_file *f, void *p) spin_lock(&skc->skc_lock); seq_printf(f, "%-36s ", skc->skc_name); seq_printf(f, "0x%05lx %9lu %9lu %8u %8u " - "%5lu %5lu %5lu %5lu %5lu %5lu %5lu %5lu\n", + "%5lu %5lu %5lu %5lu %5lu %5lu %5lu %5lu %5lu\n", (long unsigned)skc->skc_flags, (long unsigned)(skc->skc_slab_size * skc->skc_slab_total), (long unsigned)(skc->skc_obj_size * skc->skc_obj_alloc), @@ -655,6 +657,7 @@ slab_seq_show(struct seq_file *f, void *p) (long unsigned)skc->skc_obj_total, (long unsigned)skc->skc_obj_alloc, (long unsigned)skc->skc_obj_max, + (long unsigned)skc->skc_obj_deadlock, (long unsigned)skc->skc_obj_emergency, (long unsigned)skc->skc_obj_emergency_max); |