Use spl_fstrans_mark instead of memalloc_noio_save

For earlier versions of the kernel with memalloc_noio_save, it only turns
off __GFP_IO but leaves __GFP_FS untouched during direct reclaim. This
would cause threads to direct reclaim into ZFS and cause deadlock.

Instead, we should stick to using spl_fstrans_mark. Since we would
explicitly turn off both __GFP_IO and __GFP_FS before allocation, it
will work on every version of the kernel.

This impacts kernel versions 3.9-3.17, see upstream kernel commit
torvalds/linux@934f307 for reference.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes #515
Issue zfsonlinux/zfs#4111

diff --git a/include/sys/vmem.h b/include/sys/vmem.h
index eb482805206190de4fb2c041c92720c82e10479e..a9b12eeb9619aa2ba47d0528ad4a7188d52154aa 100644 (file)
--- a/include/sys/vmem.h
+++ b/include/sys/vmem.h
@@ -36,7 +36,6 @@ extern vmem_t *zio_alloc_arena;
 extern vmem_t *zio_arena;
 
 extern size_t vmem_size(vmem_t *vmp, int typemask);
-extern void *spl_vmalloc(unsigned long size, gfp_t lflags, pgprot_t prot);
 
 /*
  * Memory allocation interfaces

diff --git a/module/spl/spl-kmem-cache.c b/module/spl/spl-kmem-cache.c
index 846d2430048e546288233cf175f608ef11872dda..e3edca5a0f78ab7010c4a44f29ac5300b74d7ae1 100644 (file)
--- a/module/spl/spl-kmem-cache.c
+++ b/module/spl/spl-kmem-cache.c
@@ -201,7 +201,7 @@ kv_alloc(spl_kmem_cache_t *skc, int size, int flags)
                ASSERT(ISP2(size));
                ptr = (void *)__get_free_pages(lflags, get_order(size));
        } else {
-               ptr = spl_vmalloc(size, lflags | __GFP_HIGHMEM, PAGE_KERNEL);
+               ptr = __vmalloc(size, lflags | __GFP_HIGHMEM, PAGE_KERNEL);
        }
 
        /* Resulting allocated memory will be page aligned */
@@ -1156,15 +1156,10 @@ spl_cache_grow_work(void *data)
        spl_kmem_cache_t *skc = ska->ska_cache;
        spl_kmem_slab_t *sks;
 
-#if defined(PF_MEMALLOC_NOIO)
-       unsigned noio_flag = memalloc_noio_save();
-       sks = spl_slab_alloc(skc, ska->ska_flags);
-       memalloc_noio_restore(noio_flag);
-#else
        fstrans_cookie_t cookie = spl_fstrans_mark();
        sks = spl_slab_alloc(skc, ska->ska_flags);
        spl_fstrans_unmark(cookie);
-#endif
+
        spin_lock(&skc->skc_lock);
        if (sks) {
                skc->skc_slab_total++;

diff --git a/module/spl/spl-kmem.c b/module/spl/spl-kmem.c
index 92263f8f4ec4d8fce3514276a52ef01849a77b25..0931fdfcfd4e1291787356f4a10bae7ddaf23983 100644 (file)
--- a/module/spl/spl-kmem.c
+++ b/module/spl/spl-kmem.c
@@ -185,7 +185,7 @@ spl_kmem_alloc_impl(size_t size, int flags, int node)
                 */
                if ((size > spl_kmem_alloc_max) || use_vmem) {
                        if (flags & KM_VMEM) {
-                               ptr = spl_vmalloc(size, lflags, PAGE_KERNEL);
+                               ptr = __vmalloc(size, lflags, PAGE_KERNEL);
                        } else {
                                return (NULL);
                        }
@@ -198,7 +198,7 @@ spl_kmem_alloc_impl(size_t size, int flags, int node)
 
                /*
                 * For vmem_alloc() and vmem_zalloc() callers retry immediately
-                * using spl_vmalloc() which is unlikely to fail.
+                * using __vmalloc() which is unlikely to fail.
                 */
                if ((flags & KM_VMEM) && (use_vmem == 0))  {
                        use_vmem = 1;

diff --git a/module/spl/spl-taskq.c b/module/spl/spl-taskq.c
index db5d8fba16384cd9453fed4690bfcf0ddcc2ce57..5f2b725c98a04d5f6c66b7d2fda479d6fdcbd9a1 100644 (file)
--- a/module/spl/spl-taskq.c
+++ b/module/spl/spl-taskq.c
@@ -849,9 +849,7 @@ taskq_thread(void *args)
        tq = tqt->tqt_tq;
        current->flags |= PF_NOFREEZE;
 
-#if defined(PF_MEMALLOC_NOIO)
-       (void) memalloc_noio_save();
-#endif
+       (void) spl_fstrans_mark();
 
        sigfillset(&blocked);
        sigprocmask(SIG_BLOCK, &blocked, NULL);

diff --git a/module/spl/spl-vmem.c b/module/spl/spl-vmem.c
index bca27f263d91cd2d82b5bfc074cddfe6084e3a4e..e177988a7e2d06a509c1815058fc701e89914307 100644 (file)
--- a/module/spl/spl-vmem.c
+++ b/module/spl/spl-vmem.c
@@ -97,31 +97,6 @@ spl_vmem_free(const void *buf, size_t size)
 }
 EXPORT_SYMBOL(spl_vmem_free);
 
-/*
- * Public vmalloc() interface designed to be safe to be called during I/O.
- */
-void *
-spl_vmalloc(unsigned long size, gfp_t lflags, pgprot_t prot)
-{
-#if defined(PF_MEMALLOC_NOIO)
-       void *ptr;
-       unsigned noio_flag = 0;
-
-       if (spl_fstrans_check())
-               noio_flag = memalloc_noio_save();
-
-       ptr =  __vmalloc(size, lflags, prot);
-
-       if (spl_fstrans_check())
-               memalloc_noio_restore(noio_flag);
-
-       return (ptr);
-#else
-       return (__vmalloc(size, lflags, prot));
-#endif
-}
-EXPORT_SYMBOL(spl_vmalloc);
-
 int
 spl_vmem_init(void)
 {