Subject: [merged] mm-optimize-put_mems_allowed-usage.patch removed from -mm tree
To: mgorman@xxxxxxx,a.p.zijlstra@xxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Fri, 04 Apr 2014 12:30:58 -0700
The patch titled
Subject: mm: optimize put_mems_allowed() usage
has been removed from the -mm tree. Its filename was
mm-optimize-put_mems_allowed-usage.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxx>
Subject: mm: optimize put_mems_allowed() usage
Since put_mems_allowed() is strictly optional, its a seqcount retry, we
don't need to evaluate the function if the allocation was in fact
successful, saving a smp_rmb some loads and comparisons on some relative
fast-paths.
Since the naming, get/put_mems_allowed() does suggest a mandatory
pairing, rename the interface, as suggested by Mel, to resemble the
seqcount interface.
This gives us: read_mems_allowed_begin() and read_mems_allowed_retry(),
where it is important to note that the return value of the latter call is
inverted from its previous incarnation.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/cpuset.h | 27 ++++++++++++++-------------
kernel/cpuset.c | 2 +-
mm/filemap.c | 4 ++--
mm/hugetlb.c | 4 ++--
mm/mempolicy.c | 12 ++++++------
mm/page_alloc.c | 8 ++++----
mm/slab.c | 4 ++--
mm/slub.c | 16 +++++++---------
8 files changed, 38 insertions(+), 39 deletions(-)
diff -puN include/linux/cpuset.h~mm-optimize-put_mems_allowed-usage include/linux/cpuset.h
--- a/include/linux/cpuset.h~mm-optimize-put_mems_allowed-usage
+++ a/include/linux/cpuset.h
@@ -87,25 +87,26 @@ extern void rebuild_sched_domains(void);
extern void cpuset_print_task_mems_allowed(struct task_struct *p);
/*
- * get_mems_allowed is required when making decisions involving mems_allowed
- * such as during page allocation. mems_allowed can be updated in parallel
- * and depending on the new value an operation can fail potentially causing
- * process failure. A retry loop with get_mems_allowed and put_mems_allowed
- * prevents these artificial failures.
+ * read_mems_allowed_begin is required when making decisions involving
+ * mems_allowed such as during page allocation. mems_allowed can be updated in
+ * parallel and depending on the new value an operation can fail potentially
+ * causing process failure. A retry loop with read_mems_allowed_begin and
+ * read_mems_allowed_retry prevents these artificial failures.
*/
-static inline unsigned int get_mems_allowed(void)
+static inline unsigned int read_mems_allowed_begin(void)
{
return read_seqcount_begin(¤t->mems_allowed_seq);
}
/*
- * If this returns false, the operation that took place after get_mems_allowed
- * may have failed. It is up to the caller to retry the operation if
+ * If this returns true, the operation that took place after
+ * read_mems_allowed_begin may have failed artificially due to a concurrent
+ * update of mems_allowed. It is up to the caller to retry the operation if
* appropriate.
*/
-static inline bool put_mems_allowed(unsigned int seq)
+static inline bool read_mems_allowed_retry(unsigned int seq)
{
- return !read_seqcount_retry(¤t->mems_allowed_seq, seq);
+ return read_seqcount_retry(¤t->mems_allowed_seq, seq);
}
static inline void set_mems_allowed(nodemask_t nodemask)
@@ -225,14 +226,14 @@ static inline void set_mems_allowed(node
{
}
-static inline unsigned int get_mems_allowed(void)
+static inline unsigned int read_mems_allowed_begin(void)
{
return 0;
}
-static inline bool put_mems_allowed(unsigned int seq)
+static inline bool read_mems_allowed_retry(unsigned int seq)
{
- return true;
+ return false;
}
#endif /* !CONFIG_CPUSETS */
diff -puN kernel/cpuset.c~mm-optimize-put_mems_allowed-usage kernel/cpuset.c
--- a/kernel/cpuset.c~mm-optimize-put_mems_allowed-usage
+++ a/kernel/cpuset.c
@@ -1022,7 +1022,7 @@ static void cpuset_change_task_nodemask(
task_lock(tsk);
/*
* Determine if a loop is necessary if another thread is doing
- * get_mems_allowed(). If at least one node remains unchanged and
+ * read_mems_allowed_begin(). If at least one node remains unchanged and
* tsk does not have a mempolicy, then an empty nodemask will not be
* possible when mems_allowed is larger than a word.
*/
diff -puN mm/filemap.c~mm-optimize-put_mems_allowed-usage mm/filemap.c
--- a/mm/filemap.c~mm-optimize-put_mems_allowed-usage
+++ a/mm/filemap.c
@@ -520,10 +520,10 @@ struct page *__page_cache_alloc(gfp_t gf
if (cpuset_do_page_mem_spread()) {
unsigned int cpuset_mems_cookie;
do {
- cpuset_mems_cookie = get_mems_allowed();
+ cpuset_mems_cookie = read_mems_allowed_begin();
n = cpuset_mem_spread_node();
page = alloc_pages_exact_node(n, gfp, 0);
- } while (!put_mems_allowed(cpuset_mems_cookie) && !page);
+ } while (!page && read_mems_allowed_retry(cpuset_mems_cookie));
return page;
}
diff -puN mm/hugetlb.c~mm-optimize-put_mems_allowed-usage mm/hugetlb.c
--- a/mm/hugetlb.c~mm-optimize-put_mems_allowed-usage
+++ a/mm/hugetlb.c
@@ -540,7 +540,7 @@ static struct page *dequeue_huge_page_vm
goto err;
retry_cpuset:
- cpuset_mems_cookie = get_mems_allowed();
+ cpuset_mems_cookie = read_mems_allowed_begin();
zonelist = huge_zonelist(vma, address,
htlb_alloc_mask(h), &mpol, &nodemask);
@@ -562,7 +562,7 @@ retry_cpuset:
}
mpol_cond_put(mpol);
- if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
+ if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
goto retry_cpuset;
return page;
diff -puN mm/mempolicy.c~mm-optimize-put_mems_allowed-usage mm/mempolicy.c
--- a/mm/mempolicy.c~mm-optimize-put_mems_allowed-usage
+++ a/mm/mempolicy.c
@@ -1899,7 +1899,7 @@ int node_random(const nodemask_t *maskp)
* If the effective policy is 'BIND, returns a pointer to the mempolicy's
* @nodemask for filtering the zonelist.
*
- * Must be protected by get_mems_allowed()
+ * Must be protected by read_mems_allowed_begin()
*/
struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
gfp_t gfp_flags, struct mempolicy **mpol,
@@ -2063,7 +2063,7 @@ alloc_pages_vma(gfp_t gfp, int order, st
retry_cpuset:
pol = get_vma_policy(current, vma, addr);
- cpuset_mems_cookie = get_mems_allowed();
+ cpuset_mems_cookie = read_mems_allowed_begin();
if (unlikely(pol->mode == MPOL_INTERLEAVE)) {
unsigned nid;
@@ -2071,7 +2071,7 @@ retry_cpuset:
nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
mpol_cond_put(pol);
page = alloc_page_interleave(gfp, order, nid);
- if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
+ if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
goto retry_cpuset;
return page;
@@ -2081,7 +2081,7 @@ retry_cpuset:
policy_nodemask(gfp, pol));
if (unlikely(mpol_needs_cond_ref(pol)))
__mpol_put(pol);
- if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
+ if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
goto retry_cpuset;
return page;
}
@@ -2115,7 +2115,7 @@ struct page *alloc_pages_current(gfp_t g
pol = &default_policy;
retry_cpuset:
- cpuset_mems_cookie = get_mems_allowed();
+ cpuset_mems_cookie = read_mems_allowed_begin();
/*
* No reference counting needed for current->mempolicy
@@ -2128,7 +2128,7 @@ retry_cpuset:
policy_zonelist(gfp, pol, numa_node_id()),
policy_nodemask(gfp, pol));
- if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
+ if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
goto retry_cpuset;
return page;
diff -puN mm/page_alloc.c~mm-optimize-put_mems_allowed-usage mm/page_alloc.c
--- a/mm/page_alloc.c~mm-optimize-put_mems_allowed-usage
+++ a/mm/page_alloc.c
@@ -2739,7 +2739,7 @@ __alloc_pages_nodemask(gfp_t gfp_mask, u
return NULL;
retry_cpuset:
- cpuset_mems_cookie = get_mems_allowed();
+ cpuset_mems_cookie = read_mems_allowed_begin();
/* The preferred zone is used for statistics later */
first_zones_zonelist(zonelist, high_zoneidx,
@@ -2777,7 +2777,7 @@ out:
* the mask is being updated. If a page allocation is about to fail,
* check if the cpuset changed during allocation and if so, retry.
*/
- if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
+ if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
goto retry_cpuset;
memcg_kmem_commit_charge(page, memcg, order);
@@ -3045,9 +3045,9 @@ bool skip_free_areas_node(unsigned int f
goto out;
do {
- cpuset_mems_cookie = get_mems_allowed();
+ cpuset_mems_cookie = read_mems_allowed_begin();
ret = !node_isset(nid, cpuset_current_mems_allowed);
- } while (!put_mems_allowed(cpuset_mems_cookie));
+ } while (read_mems_allowed_retry(cpuset_mems_cookie));
out:
return ret;
}
diff -puN mm/slab.c~mm-optimize-put_mems_allowed-usage mm/slab.c
--- a/mm/slab.c~mm-optimize-put_mems_allowed-usage
+++ a/mm/slab.c
@@ -3073,7 +3073,7 @@ static void *fallback_alloc(struct kmem_
local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
retry_cpuset:
- cpuset_mems_cookie = get_mems_allowed();
+ cpuset_mems_cookie = read_mems_allowed_begin();
zonelist = node_zonelist(slab_node(), flags);
retry:
@@ -3131,7 +3131,7 @@ retry:
}
}
- if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !obj))
+ if (unlikely(!obj && read_mems_allowed_retry(cpuset_mems_cookie)))
goto retry_cpuset;
return obj;
}
diff -puN mm/slub.c~mm-optimize-put_mems_allowed-usage mm/slub.c
--- a/mm/slub.c~mm-optimize-put_mems_allowed-usage
+++ a/mm/slub.c
@@ -1684,7 +1684,7 @@ static void *get_any_partial(struct kmem
return NULL;
do {
- cpuset_mems_cookie = get_mems_allowed();
+ cpuset_mems_cookie = read_mems_allowed_begin();
zonelist = node_zonelist(slab_node(), flags);
for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
struct kmem_cache_node *n;
@@ -1696,19 +1696,17 @@ static void *get_any_partial(struct kmem
object = get_partial_node(s, n, c, flags);
if (object) {
/*
- * Return the object even if
- * put_mems_allowed indicated that
- * the cpuset mems_allowed was
- * updated in parallel. It's a
- * harmless race between the alloc
- * and the cpuset update.
+ * Don't check read_mems_allowed_retry()
+ * here - if mems_allowed was updated in
+ * parallel, that was a harmless race
+ * between allocation and the cpuset
+ * update
*/
- put_mems_allowed(cpuset_mems_cookie);
return object;
}
}
}
- } while (!put_mems_allowed(cpuset_mems_cookie));
+ } while (read_mems_allowed_retry(cpuset_mems_cookie));
#endif
return NULL;
}
_
Patches currently in -mm which might be from mgorman@xxxxxxx are
origin.patch
mm-introduce-do_shared_fault-and-drop-do_fault-fix-fix.patch
mm-numa-recheck-for-transhuge-pages-under-lock-during-protection-changes.patch
mm-numa-recheck-for-transhuge-pages-under-lock-during-protection-changes-fix.patch
mm-vmscan-restore-sc-gfp_mask-after-promoting-it-to-__gfp_highmem.patch
mm-vmscan-do-not-check-compaction_ready-on-promoted-zones.patch
mm-exclude-memory-less-nodes-from-zone_reclaim.patch
mm-compaction-disallow-high-order-page-for-migration-target.patch
mm-compaction-do-not-call-suitable_migration_target-on-every-page.patch
mm-compaction-change-the-timing-to-check-to-drop-the-spinlock.patch
mm-compaction-check-pageblock-suitability-once-per-pageblock.patch
mm-compaction-clean-up-code-on-success-of-ballon-isolation.patch
mm-revert-thp-make-madv_hugepage-check-for-mm-def_flags.patch
mm-revert-thp-make-madv_hugepage-check-for-mm-def_flags-ignore-madv_hugepage-on-s390-to-prevent-sigsegv-in-qemu.patch
mm-thp-add-vm_init_def_mask-and-prctl_thp_disable.patch
exec-kill-the-unnecessary-mm-def_flags-setting-in-load_elf_binary.patch
mm-introduce-vm_ops-map_pages.patch
mm-implement-map_pages-for-page-cache.patch
mm-cleanup-size-checks-in-filemap_fault-and-filemap_map_pages.patch
mm-add-debugfs-tunable-for-fault_around_order.patch
mm-implement-map_pages-for-shmem-tmpfs.patch
fork-collapse-copy_flags-into-copy_process.patch
mm-mempolicy-rename-slab_node-for-clarity.patch
mm-mempolicy-remove-per-process-flag.patch
res_counter-remove-interface-for-locked-charging-and-uncharging.patch
mm-compactionc-isolate_freepages_block-small-tuneup.patch
mm-compaction-determine-isolation-mode-only-once.patch
mm-page_alloc-spill-to-remote-nodes-before-waking-kswapd.patch
mm-try_to_unmap_cluster-should-lock_page-before-mlocking.patch
mm-only-force-scan-in-reclaim-when-none-of-the-lrus-are-big-enough.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
linux-next.patch
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