Now we have IS_ENABLED helper to check if a Kconfig option is enabled or not, so ZONE_DMA_FLAG sounds no longer useful.
And, the use of ZONE_DMA_FLAG in slab looks pointless according to the comment [1] from Johannes Weiner, so remove them and ORing passed in flags with the cache gfp flags has been done in kmem_getpages().
[1] https://lkml.org/lkml/2014/9/25/553
Signed-off-by: Yang Shi yang.shi@linaro.org --- Found the problem when I was reading the slab code for investigating another issue, and found a similar fix has been sent to review in 2014, but it didn't get merged into upstream. Rework the patch to adopt the comment from Johannes Weiner.
mm/Kconfig | 5 ----- mm/slab.c | 24 +----------------------- 2 files changed, 1 insertion(+), 28 deletions(-)
diff --git a/mm/Kconfig b/mm/Kconfig index 989f8f3..d6e9042 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -268,11 +268,6 @@ config ARCH_ENABLE_HUGEPAGE_MIGRATION config PHYS_ADDR_T_64BIT def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT
-config ZONE_DMA_FLAG - int - default "0" if !ZONE_DMA - default "1" - config BOUNCE bool "Enable bounce buffers" default y diff --git a/mm/slab.c b/mm/slab.c index 17e2848..3bcae12 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2138,7 +2138,7 @@ done: cachep->freelist_size = cachep->num * sizeof(freelist_idx_t); cachep->flags = flags; cachep->allocflags = __GFP_COMP; - if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA)) + if (flags & SLAB_CACHE_DMA) cachep->allocflags |= GFP_DMA; cachep->size = size; cachep->reciprocal_buffer_size = reciprocal_value(size); @@ -2438,16 +2438,6 @@ static void cache_init_objs(struct kmem_cache *cachep, } }
-static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags) -{ - if (CONFIG_ZONE_DMA_FLAG) { - if (flags & GFP_DMA) - BUG_ON(!(cachep->allocflags & GFP_DMA)); - else - BUG_ON(cachep->allocflags & GFP_DMA); - } -} - static void *slab_get_obj(struct kmem_cache *cachep, struct page *page) { void *objp; @@ -2538,14 +2528,6 @@ static int cache_grow(struct kmem_cache *cachep, local_irq_enable();
/* - * The test for missing atomic flag is performed here, rather than - * the more obvious place, simply to reduce the critical path length - * in kmem_cache_alloc(). If a caller is seriously mis-behaving they - * will eventually be caught here (where it matters). - */ - kmem_flagcheck(cachep, flags); - - /* * Get mem for the objs. Attempt to allocate a physical page from * 'nodeid'. */ @@ -2884,9 +2866,6 @@ static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep, gfp_t flags) { might_sleep_if(gfpflags_allow_blocking(flags)); -#if DEBUG - kmem_flagcheck(cachep, flags); -#endif }
#if DEBUG @@ -3044,7 +3023,6 @@ retry:
if (gfpflags_allow_blocking(local_flags)) local_irq_enable(); - kmem_flagcheck(cache, flags); page = kmem_getpages(cache, local_flags, numa_mem_id()); if (gfpflags_allow_blocking(local_flags)) local_irq_disable();