From 06089b9e1929440e07a9eb7a11e68197a4ab40f2 Mon Sep 17 00:00:00 2001 From: Brian Behlendorf <behlendorf1@llnl.gov> Date: Tue, 1 May 2012 15:49:07 -0700 Subject: [PATCH] Ensure direct reclaim forward progress The Linux direct reclaim path uses this out of band value to determine if forward progress is being made. Normally this is incremented by kmem_freepages() which is part of the various Linux slab implementations. However, since we are using none of that infrastructure we're responsible for incrementing this count. If no forward progress is detected and a subsequent allocation fails the OOM killer will be invoked. If there was forward progress additional reclaim will be attempted via the page cache and registerd shrinker until the allocation succeeds. Signed-off-by: Prakash Surya <surya1@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #107 --- module/spl/spl-kmem.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/module/spl/spl-kmem.c b/module/spl/spl-kmem.c index 361030b181..f7d5f7e86b 100644 --- a/module/spl/spl-kmem.c +++ b/module/spl/spl-kmem.c @@ -880,6 +880,16 @@ kv_free(spl_kmem_cache_t *skc, void *ptr, int size) ASSERT(IS_P2ALIGNED(ptr, PAGE_SIZE)); ASSERT(ISP2(size)); + /* + * The Linux direct reclaim path uses this out of band value to + * determine if forward progress is being made. Normally this is + * incremented by kmem_freepages() which is part of the various + * Linux slab implementations. However, since we are using none + * of that infrastructure we are responsible for incrementing it. + */ + if (current->reclaim_state) + current->reclaim_state->reclaimed_slab += size >> PAGE_SHIFT; + if (skc->skc_flags & KMC_KMEM) free_pages((unsigned long)ptr, get_order(size)); else