lkml.org 
[lkml]   [2021]   [Jun]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC v2 14/34] mm, slub: move disabling irqs closer to get_partial() in ___slab_alloc()
Date
Continue reducing the irq disabled scope. Check for per-cpu partial slabs with
first with irqs enabled and then recheck with irqs disabled before grabbing
the slab page. Mostly preparatory for the following patches.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
mm/slub.c | 34 +++++++++++++++++++++++++---------
1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 22b5bfef8aa6..acb5e8f1d9da 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2633,11 +2633,6 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
if (unlikely(node != NUMA_NO_NODE &&
!node_isset(node, slab_nodes)))
node = NUMA_NO_NODE;
- local_irq_save(flags);
- if (unlikely(c->page)) {
- local_irq_restore(flags);
- goto reread_page;
- }
goto new_slab;
}
redo:
@@ -2678,6 +2673,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,

if (!freelist) {
c->page = NULL;
+ local_irq_restore(flags);
stat(s, DEACTIVATE_BYPASS);
goto new_slab;
}
@@ -2707,12 +2703,19 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
goto reread_page;
}
deactivate_slab(s, page, c->freelist, c);
+ local_irq_restore(flags);

new_slab:

- lockdep_assert_irqs_disabled();
-
if (slub_percpu_partial(c)) {
+ local_irq_save(flags);
+ if (unlikely(c->page)) {
+ local_irq_restore(flags);
+ goto reread_page;
+ }
+ if (unlikely(!slub_percpu_partial(c)))
+ goto new_objects; /* stolen by an IRQ handler */
+
page = c->page = slub_percpu_partial(c);
slub_set_percpu_partial(c, page);
local_irq_restore(flags);
@@ -2720,6 +2723,16 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
goto redo;
}

+ local_irq_save(flags);
+ if (unlikely(c->page)) {
+ local_irq_restore(flags);
+ goto reread_page;
+ }
+
+new_objects:
+
+ lockdep_assert_irqs_disabled();
+
freelist = get_partial(s, gfpflags, node, &page);
if (freelist) {
c->page = page;
@@ -2752,15 +2765,18 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
check_new_page:

if (kmem_cache_debug(s)) {
- if (!alloc_debug_processing(s, page, freelist, addr))
+ if (!alloc_debug_processing(s, page, freelist, addr)) {
/* Slab failed checks. Next slab needed */
+ c->page = NULL;
+ local_irq_restore(flags);
goto new_slab;
- else
+ } else {
/*
* For debug case, we don't load freelist so that all
* allocations go through alloc_debug_processing()
*/
goto return_single;
+ }
}

if (unlikely(!pfmemalloc_match(page, gfpflags)))
--
2.31.1
\
 
 \ /
  Last update: 2021-06-09 13:42    [W:0.198 / U:2.568 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site