From 7835e98b2e3c66dba79cb0ff8ebb90a2fe030c29 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Wed, 22 Mar 2006 00:08:40 -0800 Subject: [PATCH] remove set_page_count() outside mm/ set_page_count usage outside mm/ is limited to setting the refcount to 1. Remove set_page_count from outside mm/, and replace those users with init_page_count() and set_page_refcounted(). This allows more debug checking, and tighter control on how code is allowed to play around with page->_count. Signed-off-by: Nick Piggin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/mm/init.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/i386/mm/init.c') diff --git a/arch/i386/mm/init.c b/arch/i386/mm/init.c index 2700f01994b..7ba55a6e2db 100644 --- a/arch/i386/mm/init.c +++ b/arch/i386/mm/init.c @@ -270,7 +270,7 @@ static void __init permanent_kmaps_init(pgd_t *pgd_base) static void __meminit free_new_highpage(struct page *page) { - set_page_count(page, 1); + init_page_count(page); __free_page(page); totalhigh_pages++; } @@ -727,7 +727,7 @@ void free_initmem(void) addr = (unsigned long)(&__init_begin); for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) { ClearPageReserved(virt_to_page(addr)); - set_page_count(virt_to_page(addr), 1); + init_page_count(virt_to_page(addr)); memset((void *)addr, 0xcc, PAGE_SIZE); free_page(addr); totalram_pages++; @@ -766,7 +766,7 @@ void free_initrd_mem(unsigned long start, unsigned long end) printk (KERN_INFO "Freeing initrd memory: %ldk freed\n", (end - start) >> 10); for (; start < end; start += PAGE_SIZE) { ClearPageReserved(virt_to_page(start)); - set_page_count(virt_to_page(start), 1); + init_page_count(virt_to_page(start)); free_page(start); totalram_pages++; } -- cgit From 9a0b5817ad97bb718ab85322759d19a238712b47 Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann Date: Thu, 23 Mar 2006 02:59:32 -0800 Subject: [PATCH] x86: SMP alternatives Implement SMP alternatives, i.e. switching at runtime between different code versions for UP and SMP. The code can patch both SMP->UP and UP->SMP. The UP->SMP case is useful for CPU hotplug. With CONFIG_CPU_HOTPLUG enabled the code switches to UP at boot time and when the number of CPUs goes down to 1, and switches to SMP when the number of CPUs goes up to 2. Without CONFIG_CPU_HOTPLUG or on non-SMP-capable systems the code is patched once at boot time (if needed) and the tables are released afterwards. The changes in detail: * The current alternatives bits are moved to a separate file, the SMP alternatives code is added there. * The patch adds some new elf sections to the kernel: .smp_altinstructions like .altinstructions, also contains a list of alt_instr structs. .smp_altinstr_replacement like .altinstr_replacement, but also has some space to save original instruction before replaving it. .smp_locks list of pointers to lock prefixes which can be nop'ed out on UP. The first two are used to replace more complex instruction sequences such as spinlocks and semaphores. It would be possible to deal with the lock prefixes with that as well, but by handling them as special case the table sizes become much smaller. * The sections are page-aligned and padded up to page size, so they can be free if they are not needed. * Splitted the code to release init pages to a separate function and use it to release the elf sections if they are unused. Signed-off-by: Gerd Hoffmann Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/mm/init.c | 45 ++++++++++++++++++++++----------------------- 1 file changed, 22 insertions(+), 23 deletions(-) (limited to 'arch/i386/mm/init.c') diff --git a/arch/i386/mm/init.c b/arch/i386/mm/init.c index 7ba55a6e2db..9f66ac582a8 100644 --- a/arch/i386/mm/init.c +++ b/arch/i386/mm/init.c @@ -720,21 +720,6 @@ static int noinline do_test_wp_bit(void) return flag; } -void free_initmem(void) -{ - unsigned long addr; - - addr = (unsigned long)(&__init_begin); - for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) { - ClearPageReserved(virt_to_page(addr)); - init_page_count(virt_to_page(addr)); - memset((void *)addr, 0xcc, PAGE_SIZE); - free_page(addr); - totalram_pages++; - } - printk (KERN_INFO "Freeing unused kernel memory: %dk freed\n", (__init_end - __init_begin) >> 10); -} - #ifdef CONFIG_DEBUG_RODATA extern char __start_rodata, __end_rodata; @@ -758,17 +743,31 @@ void mark_rodata_ro(void) } #endif +void free_init_pages(char *what, unsigned long begin, unsigned long end) +{ + unsigned long addr; + + for (addr = begin; addr < end; addr += PAGE_SIZE) { + ClearPageReserved(virt_to_page(addr)); + init_page_count(virt_to_page(addr)); + memset((void *)addr, 0xcc, PAGE_SIZE); + free_page(addr); + totalram_pages++; + } + printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10); +} + +void free_initmem(void) +{ + free_init_pages("unused kernel memory", + (unsigned long)(&__init_begin), + (unsigned long)(&__init_end)); +} #ifdef CONFIG_BLK_DEV_INITRD void free_initrd_mem(unsigned long start, unsigned long end) { - if (start < end) - printk (KERN_INFO "Freeing initrd memory: %ldk freed\n", (end - start) >> 10); - for (; start < end; start += PAGE_SIZE) { - ClearPageReserved(virt_to_page(start)); - init_page_count(virt_to_page(start)); - free_page(start); - totalram_pages++; - } + free_init_pages("initrd memory", start, end); } #endif + -- cgit