diff options
Diffstat (limited to 'sys-kernel/spl/files/spl-0.6.0_rc13-fix-soft-lockup.patch')
| -rw-r--r-- | sys-kernel/spl/files/spl-0.6.0_rc13-fix-soft-lockup.patch | 179 |
1 files changed, 0 insertions, 179 deletions
diff --git a/sys-kernel/spl/files/spl-0.6.0_rc13-fix-soft-lockup.patch b/sys-kernel/spl/files/spl-0.6.0_rc13-fix-soft-lockup.patch deleted file mode 100644 index 99227feb04a2..000000000000 --- a/sys-kernel/spl/files/spl-0.6.0_rc13-fix-soft-lockup.patch +++ /dev/null @@ -1,179 +0,0 @@ -From d4899f4747fd03be748fd1a589b9db5786fa1375 Mon Sep 17 00:00:00 2001 -From: Brian Behlendorf <behlendorf1@llnl.gov> -Date: Fri, 11 Jan 2013 14:29:32 -0800 -Subject: [PATCH] kmem-cache: Fix slab ageing soft lockup - -Commit a10287e00d13c4c4dbbff14f42b00b03da363fcb slightly reworked -the slab ageing code such that it is no longer dependent on the -Linux delayed work queue interfaces. - -This was good for portability and performance, but it requires us -to use the on_each_cpu() function to execute the spl_magazine_age() -function. That means that the function is now executing in interrupt -context whereas before it was scheduled in normal process context. -And that means we need to be slightly more careful about the locking -in the interrupt handler. - -With the reworked code it's possible that we'll be holding the -skc->skc_lock and be interrupted to handle the spl_magazine_age() -IRQ. This will result in a deadlock and soft lockup errors unless -we're careful to detect the contention and avoid taking the lock in -the interupt handler. So that's what this patch does. - -Alternately, (and slightly more conventionally) we could have used -spin_lock_irqsave() to prevent this race entirely but I'd perfer to -avoid disabling interrupts as much as possible due to performance -concerns. There is absolutely no penalty for us not aging objects -out of the magazine due to contention. - -Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> -Signed-off-by: Prakash Surya <surya1@llnl.gov> -Closes zfsonlinux/zfs#1193 ---- - module/spl/spl-kmem.c | 94 +++++++++++++++++++++++++++---------------------- - 1 file changed, 51 insertions(+), 43 deletions(-) - -diff --git a/module/spl/spl-kmem.c b/module/spl/spl-kmem.c -index bc08a55..cc5961e 100644 ---- a/module/spl/spl-kmem.c -+++ b/module/spl/spl-kmem.c -@@ -827,8 +827,7 @@ char *kvasprintf(gfp_t gfp, const char *fmt, va_list ap) - struct rw_semaphore spl_kmem_cache_sem; /* Cache list lock */ - taskq_t *spl_kmem_cache_taskq; /* Task queue for ageing / reclaim */ - --static int spl_cache_flush(spl_kmem_cache_t *skc, -- spl_kmem_magazine_t *skm, int flush); -+static void spl_cache_shrink(spl_kmem_cache_t *skc, void *obj); - - SPL_SHRINKER_CALLBACK_FWD_DECLARE(spl_kmem_cache_generic_shrinker); - SPL_SHRINKER_DECLARE(spl_kmem_cache_shrinker, -@@ -1244,6 +1243,38 @@ static int spl_cache_flush(spl_kmem_cache_t *skc, - SRETURN(0); - } - -+/* -+ * Release objects from the per-cpu magazine back to their slab. The flush -+ * argument contains the max number of entries to remove from the magazine. -+ */ -+static void -+__spl_cache_flush(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flush) -+{ -+ int i, count = MIN(flush, skm->skm_avail); -+ SENTRY; -+ -+ ASSERT(skc->skc_magic == SKC_MAGIC); -+ ASSERT(skm->skm_magic == SKM_MAGIC); -+ ASSERT(spin_is_locked(&skc->skc_lock)); -+ -+ for (i = 0; i < count; i++) -+ spl_cache_shrink(skc, skm->skm_objs[i]); -+ -+ skm->skm_avail -= count; -+ memmove(skm->skm_objs, &(skm->skm_objs[count]), -+ sizeof(void *) * skm->skm_avail); -+ -+ SEXIT; -+} -+ -+static void -+spl_cache_flush(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flush) -+{ -+ spin_lock(&skc->skc_lock); -+ __spl_cache_flush(skc, skm, flush); -+ spin_unlock(&skc->skc_lock); -+} -+ - static void - spl_magazine_age(void *data) - { -@@ -1252,10 +1283,23 @@ static int spl_cache_flush(spl_kmem_cache_t *skc, - - ASSERT(skm->skm_magic == SKM_MAGIC); - ASSERT(skm->skm_cpu == smp_processor_id()); -+ ASSERT(irqs_disabled()); -+ -+ /* There are no available objects or they are too young to age out */ -+ if ((skm->skm_avail == 0) || -+ time_before(jiffies, skm->skm_age + skc->skc_delay * HZ)) -+ return; - -- if (skm->skm_avail > 0) -- if (time_after(jiffies, skm->skm_age + skc->skc_delay * HZ)) -- (void) spl_cache_flush(skc, skm, skm->skm_refill); -+ /* -+ * Because we're executing in interrupt context we may have -+ * interrupted the holder of this lock. To avoid a potential -+ * deadlock return if the lock is contended. -+ */ -+ if (!spin_trylock(&skc->skc_lock)) -+ return; -+ -+ __spl_cache_flush(skc, skm, skm->skm_refill); -+ spin_unlock(&skc->skc_lock); - } - - /* -@@ -1451,7 +1495,7 @@ static int spl_cache_flush(spl_kmem_cache_t *skc, - - for_each_online_cpu(i) { - skm = skc->skc_mag[i]; -- (void)spl_cache_flush(skc, skm, skm->skm_avail); -+ spl_cache_flush(skc, skm, skm->skm_avail); - spl_magazine_free(skm); - } - -@@ -1932,42 +1976,6 @@ static int spl_cache_flush(spl_kmem_cache_t *skc, - } - - /* -- * Release a batch of objects from a per-cpu magazine back to their -- * respective slabs. This occurs when we exceed the magazine size, -- * are under memory pressure, when the cache is idle, or during -- * cache cleanup. The flush argument contains the number of entries -- * to remove from the magazine. -- */ --static int --spl_cache_flush(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flush) --{ -- int i, count = MIN(flush, skm->skm_avail); -- SENTRY; -- -- ASSERT(skc->skc_magic == SKC_MAGIC); -- ASSERT(skm->skm_magic == SKM_MAGIC); -- -- /* -- * XXX: Currently we simply return objects from the magazine to -- * the slabs in fifo order. The ideal thing to do from a memory -- * fragmentation standpoint is to cheaply determine the set of -- * objects in the magazine which will result in the largest -- * number of free slabs if released from the magazine. -- */ -- spin_lock(&skc->skc_lock); -- for (i = 0; i < count; i++) -- spl_cache_shrink(skc, skm->skm_objs[i]); -- -- skm->skm_avail -= count; -- memmove(skm->skm_objs, &(skm->skm_objs[count]), -- sizeof(void *) * skm->skm_avail); -- -- spin_unlock(&skc->skc_lock); -- -- SRETURN(count); --} -- --/* - * Allocate an object from the per-cpu magazine, or if the magazine - * is empty directly allocate from a slab and repopulate the magazine. - */ -@@ -2053,7 +2061,7 @@ static int spl_cache_flush(spl_kmem_cache_t *skc, - - /* Per-CPU cache full, flush it to make space */ - if (unlikely(skm->skm_avail >= skm->skm_size)) -- (void)spl_cache_flush(skc, skm, skm->skm_refill); -+ spl_cache_flush(skc, skm, skm->skm_refill); - - /* Available space in cache, use it */ - skm->skm_objs[skm->skm_avail++] = obj; --- -1.7.10 - |