The version of the patch to protect executable pages that is on its way upstream.

-------- Original Message -------- Subject: [PATCH -mm] vmscan: make mapped executable pages the first class citizen Date: Thu, 7 May 2009 20:11:01 +0800 From: Wu Fengguang fengguang.wu@intel.com To: Andrew Morton akpm@linux-foundation.org CC: Peter Zijlstra peterz@infradead.org, Rik van Riel riel@redhat.com, "linux-kernel@vger.kernel.org" linux-kernel@vger.kernel.org, "tytso@mit.edu" tytso@mit.edu, "linux-mm@kvack.org" linux-mm@kvack.org, Elladan elladan@eskimo.com, Nick Piggin npiggin@suse.de, Johannes Weiner hannes@cmpxchg.org, Christoph Lameter cl@linux-foundation.org, KOSAKI Motohiro kosaki.motohiro@jp.fujitsu.com References: 20090430072057.GA4663@eskimo.com 20090430174536.d0f438dd.akpm@linux-foundation.org 20090430205936.0f8b29fc@riellaptop.surriel.com 20090430181340.6f07421d.akpm@linux-foundation.org 20090430215034.4748e615@riellaptop.surriel.com 20090430195439.e02edc26.akpm@linux-foundation.org 49FB01C1.6050204@redhat.com 20090501123541.7983a8ae.akpm@linux-foundation.org 20090503031539.GC5702@localhost 1241432635.7620.4732.camel@twins

Introduce AS_EXEC to mark executables and their linked libraries, and to protect their referenced active pages from being deactivated.

CC: Elladan elladan@eskimo.com CC: Nick Piggin npiggin@suse.de CC: Johannes Weiner hannes@cmpxchg.org CC: Christoph Lameter cl@linux-foundation.org CC: KOSAKI Motohiro kosaki.motohiro@jp.fujitsu.com Acked-by: Peter Zijlstra peterz@infradead.org Acked-by: Rik van Riel riel@redhat.com Signed-off-by: Wu Fengguang fengguang.wu@intel.com --- include/linux/pagemap.h | 1 + mm/mmap.c | 2 ++ mm/nommu.c | 2 ++ mm/vmscan.c | 35 +++++++++++++++++++++++++++++++++-- 4 files changed, 38 insertions(+), 2 deletions(-)

--- linux.orig/include/linux/pagemap.h +++ linux/include/linux/pagemap.h @@ -25,6 +25,7 @@ enum mapping_flags { #ifdef CONFIG_UNEVICTABLE_LRU AS_UNEVICTABLE = __GFP_BITS_SHIFT + 3, /* e.g., ramdisk, SHM_LOCK */ #endif + AS_EXEC = __GFP_BITS_SHIFT + 4, /* mapped PROT_EXEC somewhere */ };

static inline void mapping_set_error(struct address_space *mapping, int error) --- linux.orig/mm/mmap.c +++ linux/mm/mmap.c @@ -1194,6 +1194,8 @@ munmap_back: goto unmap_and_free_vma; if (vm_flags & VM_EXECUTABLE) added_exe_file_vma(mm); + if (vm_flags & VM_EXEC) + set_bit(AS_EXEC, &file->f_mapping->flags); } else if (vm_flags & VM_SHARED) { error = shmem_zero_setup(vma); if (error) --- linux.orig/mm/nommu.c +++ linux/mm/nommu.c @@ -1224,6 +1224,8 @@ unsigned long do_mmap_pgoff(struct file added_exe_file_vma(current->mm); vma->vm_mm = current->mm; } + if (vm_flags & VM_EXEC) + set_bit(AS_EXEC, &file->f_mapping->flags); }

down_write(&nommu_region_sem); --- linux.orig/mm/vmscan.c +++ linux/mm/vmscan.c @@ -1230,6 +1230,7 @@ static void shrink_active_list(unsigned unsigned long pgmoved; unsigned long pgscanned; LIST_HEAD(l_hold); /* The pages which were snipped off */ + LIST_HEAD(l_active); LIST_HEAD(l_inactive); struct page *page; struct pagevec pvec; @@ -1269,8 +1270,15 @@ static void shrink_active_list(unsigned

/* page_referenced clears PageReferenced */ if (page_mapping_inuse(page) && - page_referenced(page, 0, sc->mem_cgroup)) + page_referenced(page, 0, sc->mem_cgroup)) { + struct address_space *mapping = page_mapping(page); + pgmoved++; + if (mapping && test_bit(AS_EXEC, &mapping->flags)) { + list_add(&page->lru, &l_active); + continue; + } + }

list_add(&page->lru, &l_inactive); } @@ -1279,7 +1287,6 @@ static void shrink_active_list(unsigned * Move the pages to the [file or anon] inactive list. */ pagevec_init(&pvec, 1); - lru = LRU_BASE + file * LRU_FILE;

spin_lock_irq(&zone->lru_lock); /* @@ -1291,6 +1298,7 @@ static void shrink_active_list(unsigned reclaim_stat->recent_rotated[!!file] += pgmoved;

pgmoved = 0; /* count pages moved to inactive list */ + lru = LRU_BASE + file * LRU_FILE; while (!list_empty(&l_inactive)) { page = lru_to_page(&l_inactive); prefetchw_prev_lru_page(page, &l_inactive, flags); @@ -1313,6 +1321,29 @@ static void shrink_active_list(unsigned __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved); __count_zone_vm_events(PGREFILL, zone, pgscanned); __count_vm_events(PGDEACTIVATE, pgmoved); + + pgmoved = 0; /* count pages moved back to active list */ + lru = LRU_ACTIVE + file * LRU_FILE; + while (!list_empty(&l_active)) { + page = lru_to_page(&l_active); + prefetchw_prev_lru_page(page, &l_active, flags); + VM_BUG_ON(PageLRU(page)); + SetPageLRU(page); + VM_BUG_ON(!PageActive(page)); + + list_move(&page->lru, &zone->lru[lru].list); + mem_cgroup_add_lru_list(page, lru); + pgmoved++; + if (!pagevec_add(&pvec, page)) { + spin_unlock_irq(&zone->lru_lock); + if (buffer_heads_over_limit) + pagevec_strip(&pvec); + __pagevec_release(&pvec); + spin_lock_irq(&zone->lru_lock); + } + } + __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved); + spin_unlock_irq(&zone->lru_lock); if (buffer_heads_over_limit) pagevec_strip(&pvec);