From 68126702b419fd26ef4946e314bb3a1f57d3a53f Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Thu, 24 Oct 2013 10:07:42 +0900 Subject: slab: overloading the RCU head over the LRU for RCU free With build-time size checking, we can overload the RCU head over the LRU of struct page to free pages of a slab in rcu context. This really help to implement to overload the struct slab over the struct page and this eventually reduce memory usage and cache footprint of the SLAB. Acked-by: Andi Kleen Acked-by: Christoph Lameter Signed-off-by: Joonsoo Kim Signed-off-by: Pekka Enberg --- include/linux/mm_types.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/mm_types.h') diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index faf4b7c1ad12..959cb369b197 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -130,6 +130,9 @@ struct page { struct list_head list; /* slobs list of pages */ struct slab *slab_page; /* slab fields */ + struct rcu_head rcu_head; /* Used by SLAB + * when destroying via RCU + */ }; /* Remainder is not double word aligned */ -- cgit v1.2.3 From 8456a648cf44f14365f1f44de90a3da2526a4776 Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Thu, 24 Oct 2013 10:07:49 +0900 Subject: slab: use struct page for slab management Now, there are a few field in struct slab, so we can overload these over struct page. This will save some memory and reduce cache footprint. After this change, slabp_cache and slab_size no longer related to a struct slab, so rename them as freelist_cache and freelist_size. These changes are just mechanical ones and there is no functional change. Acked-by: Andi Kleen Acked-by: Christoph Lameter Signed-off-by: Joonsoo Kim Signed-off-by: Pekka Enberg --- include/linux/mm_types.h | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) (limited to 'include/linux/mm_types.h') diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 959cb369b197..95bf0c5a7eb9 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -42,18 +42,22 @@ struct page { /* First double word block */ unsigned long flags; /* Atomic flags, some possibly * updated asynchronously */ - struct address_space *mapping; /* If low bit clear, points to - * inode address_space, or NULL. - * If page mapped as anonymous - * memory, low bit is set, and - * it points to anon_vma object: - * see PAGE_MAPPING_ANON below. - */ + union { + struct address_space *mapping; /* If low bit clear, points to + * inode address_space, or NULL. + * If page mapped as anonymous + * memory, low bit is set, and + * it points to anon_vma object: + * see PAGE_MAPPING_ANON below. + */ + void *s_mem; /* slab first object */ + }; + /* Second double word */ struct { union { pgoff_t index; /* Our offset within mapping. */ - void *freelist; /* slub/slob first free object */ + void *freelist; /* sl[aou]b first free object */ bool pfmemalloc; /* If set by the page allocator, * ALLOC_NO_WATERMARKS was set * and the low watermark was not @@ -109,6 +113,7 @@ struct page { }; atomic_t _count; /* Usage count, see below. */ }; + unsigned int active; /* SLAB */ }; }; -- cgit v1.2.3 From 7aa555bf26763b86332c7a3689701c999834b87a Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Thu, 21 Nov 2013 14:32:11 -0800 Subject: mm: place page->pmd_huge_pte to right union I don't know what went wrong, mis-merge or something, but ->pmd_huge_pte placed in wrong union within struct page. In original patch[1] it's placed to union with ->lru and ->slab, but in commit e009bb30c8df ("mm: implement split page table lock for PMD level") it's in union with ->index and ->freelist. That union seems also unused for pages with table tables and safe to re-use, but it's not what I've tested. Let's move it to original place. It fixes indentation at least. :) [1] https://lkml.org/lkml/2013/10/7/288 Signed-off-by: Kirill A. Shutemov Reviewed-by: Naoya Horiguchi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm_types.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/linux/mm_types.h') diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 10f5a7272b80..011eb85d7b0f 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -65,9 +65,6 @@ struct page { * this page is only used to * free other pages. */ -#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS - pgtable_t pmd_huge_pte; /* protected by page->ptl */ -#endif }; union { @@ -135,6 +132,9 @@ struct page { struct list_head list; /* slobs list of pages */ struct slab *slab_page; /* slab fields */ +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS + pgtable_t pmd_huge_pte; /* protected by page->ptl */ +#endif }; /* Remainder is not double word aligned */ -- cgit v1.2.3