From 71088785c6bc68fddb450063d57b1bd1c78e0ea1 Mon Sep 17 00:00:00 2001 From: Badari Pulavarty Date: Sat, 18 Oct 2008 20:25:58 -0700 Subject: mm: cleanup to make remove_memory() arch-neutral There is nothing architecture specific about remove_memory(). remove_memory() function is common for all architectures which support hotplug memory remove. Instead of duplicating it in every architecture, collapse them into arch neutral function. [akpm@linux-foundation.org: fix the export] Signed-off-by: Badari Pulavarty Cc: Yasunori Goto Cc: Gary Hade Cc: Mel Gorman Cc: Yasunori Goto Cc: "Luck, Tony" Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Heiko Carstens Cc: Martin Schwidefsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory_hotplug.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'mm/memory_hotplug.c') diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 89fee2dcb039..c299d083d8e2 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -26,6 +26,7 @@ #include #include #include +#include #include @@ -849,10 +850,19 @@ failed_removal: return ret; } + +int remove_memory(u64 start, u64 size) +{ + unsigned long start_pfn, end_pfn; + + start_pfn = PFN_DOWN(start); + end_pfn = start_pfn + PFN_DOWN(size); + return offline_pages(start_pfn, end_pfn, 120 * HZ); +} #else int remove_memory(u64 start, u64 size) { return -EINVAL; } -EXPORT_SYMBOL_GPL(remove_memory); #endif /* CONFIG_MEMORY_HOTREMOVE */ +EXPORT_SYMBOL_GPL(remove_memory); -- cgit v1.2.2 From 62695a84eb8f2e718bf4dfb21700afaa7a08e0ea Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Sat, 18 Oct 2008 20:26:09 -0700 Subject: vmscan: move isolate_lru_page() to vmscan.c On large memory systems, the VM can spend way too much time scanning through pages that it cannot (or should not) evict from memory. Not only does it use up CPU time, but it also provokes lock contention and can leave large systems under memory presure in a catatonic state. This patch series improves VM scalability by: 1) putting filesystem backed, swap backed and unevictable pages onto their own LRUs, so the system only scans the pages that it can/should evict from memory 2) switching to two handed clock replacement for the anonymous LRUs, so the number of pages that need to be scanned when the system starts swapping is bound to a reasonable number 3) keeping unevictable pages off the LRU completely, so the VM does not waste CPU time scanning them. ramfs, ramdisk, SHM_LOCKED shared memory segments and mlock()ed VMA pages are keept on the unevictable list. This patch: isolate_lru_page logically belongs to be in vmscan.c than migrate.c. It is tough, because we don't need that function without memory migration so there is a valid argument to have it in migrate.c. However a subsequent patch needs to make use of it in the core mm, so we can happily move it to vmscan.c. Also, make the function a little more generic by not requiring that it adds an isolated page to a given list. Callers can do that. Note that we now have '__isolate_lru_page()', that does something quite different, visible outside of vmscan.c for use with memory controller. Methinks we need to rationalize these names/purposes. --lts [akpm@linux-foundation.org: fix mm/memory_hotplug.c build] Signed-off-by: Nick Piggin Signed-off-by: Rik van Riel Signed-off-by: Lee Schermerhorn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory_hotplug.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'mm/memory_hotplug.c') diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index c299d083d8e2..3b4975815141 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -658,8 +658,9 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) * We can skip free pages. And we can only deal with pages on * LRU. */ - ret = isolate_lru_page(page, &source); + ret = isolate_lru_page(page); if (!ret) { /* Success */ + list_add_tail(&page->lru, &source); move_pages--; } else { /* Becasue we don't have big zone->lock. we should -- cgit v1.2.2 From de7f0cba96786cf9ec9da4532c1b25f733da9b6f Mon Sep 17 00:00:00 2001 From: Nathan Fontenot Date: Sat, 18 Oct 2008 20:27:14 -0700 Subject: memory hotplug: release memory regions in PAGES_PER_SECTION chunks During hotplug memory remove, memory regions should be released on a PAGES_PER_SECTION size chunks. This mirrors the code in add_memory where resources are requested on a PAGES_PER_SECTION size. Attempting to release the entire memory region fails because there is not a single resource for the total number of pages being removed. Instead the resources for the pages are split in PAGES_PER_SECTION size chunks as requested during memory add. Signed-off-by: Nathan Fontenot Signed-off-by: Badari Pulavarty Acked-by: Yasunori Goto Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory_hotplug.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'mm/memory_hotplug.c') diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 3b4975815141..6837a1014372 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -324,11 +324,11 @@ int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK); BUG_ON(nr_pages % PAGES_PER_SECTION); - release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE); - sections_to_remove = nr_pages / PAGES_PER_SECTION; for (i = 0; i < sections_to_remove; i++) { unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION; + release_mem_region(pfn << PAGE_SHIFT, + PAGES_PER_SECTION << PAGE_SHIFT); ret = __remove_section(zone, __pfn_to_section(pfn)); if (ret) break; -- cgit v1.2.2