diff options
| author | Brian Behlendorf <[email protected]> | 2015-01-29 16:08:25 -0800 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2015-02-02 10:57:56 -0800 |
| commit | c7db36a3c4ac768a74bd86778cc3535bdcb8d526 (patch) | |
| tree | 3ba5c7c1d6f8b6f28d9a26e7e373fcf39722ef02 | |
| parent | 54cccfc2e30fa84463c056e8ad04b2be9448999e (diff) | |
Optimize vmem_alloc() retry path
For performance reasons the reworked kmem code maps vmem_alloc() to
kmalloc_node() for allocations less than spa_kmem_alloc_max. This
allows for more concurrency in the system and less contention of
the virtual address space. Generally, this is a good thing.
However, in the case when the kmalloc_node() fails it makes little
sense to retry it using kmalloc_node() again. It will likely fail
in exactly the same way. A smarter strategy is to abandon this
optimization and retry using spl_vmalloc() which is very likely
to succeed.
Signed-off-by: Brian Behlendorf <[email protected]>
Signed-off-by: Ned Bass <[email protected]>
Closes #428
| -rw-r--r-- | module/spl/spl-kmem.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/module/spl/spl-kmem.c b/module/spl/spl-kmem.c index e97d5f255..92263f8f4 100644 --- a/module/spl/spl-kmem.c +++ b/module/spl/spl-kmem.c @@ -149,6 +149,7 @@ inline void * spl_kmem_alloc_impl(size_t size, int flags, int node) { gfp_t lflags = kmem_flags_convert(flags); + int use_vmem = 0; void *ptr; /* @@ -182,7 +183,7 @@ spl_kmem_alloc_impl(size_t size, int flags, int node) * impact performance so frequently manipulating the virtual * address space is strongly discouraged. */ - if (unlikely(size > spl_kmem_alloc_max)) { + if ((size > spl_kmem_alloc_max) || use_vmem) { if (flags & KM_VMEM) { ptr = spl_vmalloc(size, lflags, PAGE_KERNEL); } else { @@ -195,6 +196,15 @@ spl_kmem_alloc_impl(size_t size, int flags, int node) if (likely(ptr) || (flags & KM_NOSLEEP)) return (ptr); + /* + * For vmem_alloc() and vmem_zalloc() callers retry immediately + * using spl_vmalloc() which is unlikely to fail. + */ + if ((flags & KM_VMEM) && (use_vmem == 0)) { + use_vmem = 1; + continue; + } + if (unlikely(__ratelimit(&kmem_alloc_ratelimit_state))) { printk(KERN_WARNING "Possible memory allocation deadlock: " |