From: Alexander Duyck <alexander.h.duyck@linux.intel.com> To: linux-mm@kvack.org, akpm@linux-foundation.org Cc: pavel.tatashin@microsoft.com, mhocko@suse.com, dave.jiang@intel.com, alexander.h.duyck@linux.intel.com, linux-kernel@vger.kernel.org, willy@infradead.org, davem@davemloft.net, yi.z.zhang@linux.intel.com, khalid.aziz@oracle.com, rppt@linux.vnet.ibm.com, vbabka@suse.cz, sparclinux@vger.kernel.org, dan.j.williams@intel.com, ldufour@linux.vnet.ibm.com, mgorman@techsingularity.net, mingo@kernel.org, kirill.shutemov@linux.intel.com Subject: [mm PATCH v4 5/6] mm: Add reserved flag setting to set_page_links Date: Wed, 17 Oct 2018 16:54:31 -0700 [thread overview] Message-ID: <20181017235431.17213.11512.stgit@localhost.localdomain> (raw) In-Reply-To: <20181017235043.17213.92459.stgit@localhost.localdomain> This patch modifies the set_page_links function to include the setting of the reserved flag via a simple AND and OR operation. The motivation for this is the fact that the existing __set_bit call still seems to have effects on performance as replacing the call with the AND and OR can reduce initialization time. Looking over the assembly code before and after the change the main difference between the two is that the reserved bit is stored in a value that is generated outside of the main initialization loop and is then written with the other flags field values in one write to the page->flags value. Previously the generated value was written and then then a btsq instruction was issued. On my x86_64 test system with 3TB of persistent memory per node I saw the persistent memory initialization time on average drop from 23.49s to 19.12s per node. Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> --- include/linux/mm.h | 9 ++++++++- mm/page_alloc.c | 29 +++++++++++++++++++---------- 2 files changed, 27 insertions(+), 11 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 6e2c9631af05..14d06d7d2986 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1171,11 +1171,18 @@ static inline void set_page_node(struct page *page, unsigned long node) page->flags |= (node & NODES_MASK) << NODES_PGSHIFT; } +static inline void set_page_reserved(struct page *page, bool reserved) +{ + page->flags &= ~(1ul << PG_reserved); + page->flags |= (unsigned long)(!!reserved) << PG_reserved; +} + static inline void set_page_links(struct page *page, enum zone_type zone, - unsigned long node, unsigned long pfn) + unsigned long node, unsigned long pfn, bool reserved) { set_page_zone(page, zone); set_page_node(page, node); + set_page_reserved(page, reserved); #ifdef SECTION_IN_PAGE_FLAGS set_page_section(page, pfn_to_section_nr(pfn)); #endif diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a0b81e0bef03..e7fee7a5f8a3 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1179,7 +1179,7 @@ static void __meminit __init_single_page(struct page *page, unsigned long pfn, unsigned long zone, int nid) { mm_zero_struct_page(page); - set_page_links(page, zone, nid, pfn); + set_page_links(page, zone, nid, pfn, false); init_page_count(page); page_mapcount_reset(page); page_cpupid_reset_last(page); @@ -1195,7 +1195,8 @@ static void __meminit __init_single_page(struct page *page, unsigned long pfn, static void __meminit __init_pageblock(unsigned long start_pfn, unsigned long nr_pages, unsigned long zone, int nid, - struct dev_pagemap *pgmap) + struct dev_pagemap *pgmap, + bool is_reserved) { unsigned long nr_pgmask = pageblock_nr_pages - 1; struct page *start_page = pfn_to_page(start_pfn); @@ -1231,19 +1232,16 @@ static void __meminit __init_pageblock(unsigned long start_pfn, * call because of the fact that the pfn number is used to * get the section_nr and this function should not be * spanning more than a single section. + * + * We can use a non-atomic operation for setting the + * PG_reserved flag as we are still initializing the pages. */ - set_page_links(page, zone, nid, start_pfn); + set_page_links(page, zone, nid, start_pfn, is_reserved); init_page_count(page); page_mapcount_reset(page); page_cpupid_reset_last(page); /* - * We can use the non-atomic __set_bit operation for setting - * the flag as we are still initializing the pages. - */ - __SetPageReserved(page); - - /* * ZONE_DEVICE pages union ->lru with a ->pgmap back * pointer and hmm_data. It is a bug if a ZONE_DEVICE * page is ever freed or placed on a driver-private list. @@ -5612,7 +5610,18 @@ static void __meminit __memmap_init_hotplug(unsigned long size, int nid, pfn = max(ALIGN_DOWN(pfn - 1, pageblock_nr_pages), start_pfn); stride -= pfn; - __init_pageblock(pfn, stride, zone, nid, pgmap); + /* + * The last argument of __init_pageblock is a boolean + * value indicating if the page will be marked as reserved. + * + * Mark page reserved as it will need to wait for onlining + * phase for it to be fully associated with a zone. + * + * Under certain circumstances ZONE_DEVICE pages may not + * need to be marked as reserved, however there is still + * code that is depending on this being set for now. + */ + __init_pageblock(pfn, stride, zone, nid, pgmap, true); cond_resched(); }
WARNING: multiple messages have this Message-ID (diff)
From: Alexander Duyck <alexander.h.duyck@linux.intel.com> To: linux-mm@kvack.org, akpm@linux-foundation.org Cc: pavel.tatashin@microsoft.com, mhocko@suse.com, dave.jiang@intel.com, alexander.h.duyck@linux.intel.com, linux-kernel@vger.kernel.org, willy@infradead.org, davem@davemloft.net, yi.z.zhang@linux.intel.com, khalid.aziz@oracle.com, rppt@linux.vnet.ibm.com, vbabka@suse.cz, sparclinux@vger.kernel.org, dan.j.williams@intel.com, ldufour@linux.vnet.ibm.com, mgorman@techsingularity.net, mingo@kernel.org, kirill.shutemov@linux.intel.com Subject: [mm PATCH v4 5/6] mm: Add reserved flag setting to set_page_links Date: Wed, 17 Oct 2018 23:54:31 +0000 [thread overview] Message-ID: <20181017235431.17213.11512.stgit@localhost.localdomain> (raw) In-Reply-To: <20181017235043.17213.92459.stgit@localhost.localdomain> This patch modifies the set_page_links function to include the setting of the reserved flag via a simple AND and OR operation. The motivation for this is the fact that the existing __set_bit call still seems to have effects on performance as replacing the call with the AND and OR can reduce initialization time. Looking over the assembly code before and after the change the main difference between the two is that the reserved bit is stored in a value that is generated outside of the main initialization loop and is then written with the other flags field values in one write to the page->flags value. Previously the generated value was written and then then a btsq instruction was issued. On my x86_64 test system with 3TB of persistent memory per node I saw the persistent memory initialization time on average drop from 23.49s to 19.12s per node. Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> --- include/linux/mm.h | 9 ++++++++- mm/page_alloc.c | 29 +++++++++++++++++++---------- 2 files changed, 27 insertions(+), 11 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 6e2c9631af05..14d06d7d2986 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1171,11 +1171,18 @@ static inline void set_page_node(struct page *page, unsigned long node) page->flags |= (node & NODES_MASK) << NODES_PGSHIFT; } +static inline void set_page_reserved(struct page *page, bool reserved) +{ + page->flags &= ~(1ul << PG_reserved); + page->flags |= (unsigned long)(!!reserved) << PG_reserved; +} + static inline void set_page_links(struct page *page, enum zone_type zone, - unsigned long node, unsigned long pfn) + unsigned long node, unsigned long pfn, bool reserved) { set_page_zone(page, zone); set_page_node(page, node); + set_page_reserved(page, reserved); #ifdef SECTION_IN_PAGE_FLAGS set_page_section(page, pfn_to_section_nr(pfn)); #endif diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a0b81e0bef03..e7fee7a5f8a3 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1179,7 +1179,7 @@ static void __meminit __init_single_page(struct page *page, unsigned long pfn, unsigned long zone, int nid) { mm_zero_struct_page(page); - set_page_links(page, zone, nid, pfn); + set_page_links(page, zone, nid, pfn, false); init_page_count(page); page_mapcount_reset(page); page_cpupid_reset_last(page); @@ -1195,7 +1195,8 @@ static void __meminit __init_single_page(struct page *page, unsigned long pfn, static void __meminit __init_pageblock(unsigned long start_pfn, unsigned long nr_pages, unsigned long zone, int nid, - struct dev_pagemap *pgmap) + struct dev_pagemap *pgmap, + bool is_reserved) { unsigned long nr_pgmask = pageblock_nr_pages - 1; struct page *start_page = pfn_to_page(start_pfn); @@ -1231,19 +1232,16 @@ static void __meminit __init_pageblock(unsigned long start_pfn, * call because of the fact that the pfn number is used to * get the section_nr and this function should not be * spanning more than a single section. + * + * We can use a non-atomic operation for setting the + * PG_reserved flag as we are still initializing the pages. */ - set_page_links(page, zone, nid, start_pfn); + set_page_links(page, zone, nid, start_pfn, is_reserved); init_page_count(page); page_mapcount_reset(page); page_cpupid_reset_last(page); /* - * We can use the non-atomic __set_bit operation for setting - * the flag as we are still initializing the pages. - */ - __SetPageReserved(page); - - /* * ZONE_DEVICE pages union ->lru with a ->pgmap back * pointer and hmm_data. It is a bug if a ZONE_DEVICE * page is ever freed or placed on a driver-private list. @@ -5612,7 +5610,18 @@ static void __meminit __memmap_init_hotplug(unsigned long size, int nid, pfn = max(ALIGN_DOWN(pfn - 1, pageblock_nr_pages), start_pfn); stride -= pfn; - __init_pageblock(pfn, stride, zone, nid, pgmap); + /* + * The last argument of __init_pageblock is a boolean + * value indicating if the page will be marked as reserved. + * + * Mark page reserved as it will need to wait for onlining + * phase for it to be fully associated with a zone. + * + * Under certain circumstances ZONE_DEVICE pages may not + * need to be marked as reserved, however there is still + * code that is depending on this being set for now. + */ + __init_pageblock(pfn, stride, zone, nid, pgmap, true); cond_resched(); }
next prev parent reply other threads:[~2018-10-17 23:54 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-10-17 23:54 [mm PATCH v4 0/6] Deferred page init improvements Alexander Duyck 2018-10-17 23:54 ` Alexander Duyck 2018-10-17 23:54 ` [mm PATCH v4 1/6] mm: Use mm_zero_struct_page from SPARC on all 64b architectures Alexander Duyck 2018-10-17 23:54 ` Alexander Duyck 2018-10-18 18:29 ` Pavel Tatashin 2018-10-18 18:29 ` Pavel Tatashin 2018-10-29 20:12 ` Michal Hocko 2018-10-29 20:12 ` Michal Hocko 2018-10-17 23:54 ` [mm PATCH v4 2/6] mm: Drop meminit_pfn_in_nid as it is redundant Alexander Duyck 2018-10-17 23:54 ` Alexander Duyck 2018-10-17 23:54 ` [mm PATCH v4 3/6] mm: Use memblock/zone specific iterator for handling deferred page init Alexander Duyck 2018-10-17 23:54 ` Alexander Duyck 2018-10-31 15:40 ` Pasha Tatashin 2018-10-31 15:40 ` Pasha Tatashin 2018-10-31 16:05 ` Alexander Duyck 2018-10-31 16:05 ` Alexander Duyck 2018-10-31 16:06 ` Pasha Tatashin 2018-10-31 16:06 ` Pasha Tatashin 2018-11-01 6:17 ` Mike Rapoport 2018-11-01 6:17 ` Mike Rapoport 2018-11-01 15:10 ` Alexander Duyck 2018-11-01 15:10 ` Alexander Duyck 2018-10-17 23:54 ` [mm PATCH v4 4/6] mm: Move hot-plug specific memory init into separate functions and optimize Alexander Duyck 2018-10-17 23:54 ` Alexander Duyck 2018-10-17 23:54 ` Alexander Duyck [this message] 2018-10-17 23:54 ` [mm PATCH v4 5/6] mm: Add reserved flag setting to set_page_links Alexander Duyck 2018-10-17 23:54 ` [mm PATCH v4 6/6] mm: Use common iterator for deferred_init_pages and deferred_free_pages Alexander Duyck 2018-10-17 23:54 ` Alexander Duyck
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