Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932173Ab1E0Ttt (ORCPT ); Fri, 27 May 2011 15:49:49 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:54294 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932072Ab1E0Tts (ORCPT ); Fri, 27 May 2011 15:49:48 -0400 Date: Fri, 27 May 2011 12:49:05 -0700 From: Dan Magenheimer To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, jeremy@goop.org, hughd@google.com, ngupta@vflare.org, konrad.wilk@oracle.com, JBeulich@novell.com, kurt.hackel@oracle.com, npiggin@suse.de, akpm@linux-foundation.org, riel@redhat.com, hannes@cmpxchg.org, matthew@wil.cx, chris.mason@oracle.com, dan.magenheimer@oracle.com Subject: [PATCH V4 3/4] mm: frontswap: add hooks in swap subsystem and extend Message-ID: <20110527194905.GA27185@ca-server1.us.oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.16 (2007-06-11) X-Source-IP: acsinet21.oracle.com [141.146.126.237] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090201.4DE0003A.011D:SCFMA922111,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8033 Lines: 251 [PATCH V4 3/4] mm: frontswap: add hooks in swap subsystem and extend try_to_unuse so that frontswap_shrink can do a "partial swapoff" Signed-off-by: Dan Magenheimer Diffstat: page_io.c | 12 ++++ swapfile.c | 58 +++++++++++++++++---- 2 files changed, 61 insertions(+), 9 deletions(-) --- linux-2.6.39/mm/swapfile.c 2011-05-18 22:06:34.000000000 -0600 +++ linux-2.6.39-frontswap/mm/swapfile.c 2011-05-26 15:48:09.665832190 -0600 @@ -31,6 +31,8 @@ #include #include #include +#include +#include #include #include @@ -42,7 +44,7 @@ static bool swap_count_continued(struct static void free_swap_count_continuations(struct swap_info_struct *); static sector_t map_swap_entry(swp_entry_t, struct block_device**); -static DEFINE_SPINLOCK(swap_lock); +DEFINE_SPINLOCK(swap_lock); static unsigned int nr_swapfiles; long nr_swap_pages; long total_swap_pages; @@ -53,9 +55,9 @@ static const char Unused_file[] = "Unuse static const char Bad_offset[] = "Bad swap offset entry "; static const char Unused_offset[] = "Unused swap offset entry "; -static struct swap_list_t swap_list = {-1, -1}; +struct swap_list_t swap_list = {-1, -1}; -static struct swap_info_struct *swap_info[MAX_SWAPFILES]; +struct swap_info_struct *swap_info[MAX_SWAPFILES]; static DEFINE_MUTEX(swapon_mutex); @@ -556,6 +558,7 @@ static unsigned char swap_entry_free(str swap_list.next = p->type; nr_swap_pages++; p->inuse_pages--; + frontswap_flush_page(p->type, offset); if ((p->flags & SWP_BLKDEV) && disk->fops->swap_slot_free_notify) disk->fops->swap_slot_free_notify(p->bdev, offset); @@ -1021,7 +1024,7 @@ static int unuse_mm(struct mm_struct *mm * Recycle to start on reaching the end, returning 0 when empty. */ static unsigned int find_next_to_unuse(struct swap_info_struct *si, - unsigned int prev) + unsigned int prev, bool frontswap) { unsigned int max = si->max; unsigned int i = prev; @@ -1047,6 +1050,12 @@ static unsigned int find_next_to_unuse(s prev = 0; i = 1; } + if (frontswap) { + if (frontswap_test(si, i)) + break; + else + continue; + } count = si->swap_map[i]; if (count && swap_count(count) != SWAP_MAP_BAD) break; @@ -1058,8 +1067,12 @@ static unsigned int find_next_to_unuse(s * We completely avoid races by reading each swap page in advance, * and then search for the process using it. All the necessary * page table adjustments can then be made atomically. + * + * if the boolean frontswap is true, only unuse pages_to_unuse pages; + * pages_to_unuse==0 means all pages */ -static int try_to_unuse(unsigned int type) +int try_to_unuse(unsigned int type, bool frontswap, + unsigned long pages_to_unuse) { struct swap_info_struct *si = swap_info[type]; struct mm_struct *start_mm; @@ -1092,7 +1105,7 @@ static int try_to_unuse(unsigned int typ * one pass through swap_map is enough, but not necessarily: * there are races when an instance of an entry might be missed. */ - while ((i = find_next_to_unuse(si, i)) != 0) { + while ((i = find_next_to_unuse(si, i, frontswap)) != 0) { if (signal_pending(current)) { retval = -EINTR; break; @@ -1259,6 +1272,10 @@ static int try_to_unuse(unsigned int typ * interactive performance. */ cond_resched(); + if (frontswap && pages_to_unuse > 0) { + if (!--pages_to_unuse) + break; + } } mmput(start_mm); @@ -1528,6 +1545,7 @@ static void enable_swap_info(struct swap else p->prio = --least_priority; p->swap_map = swap_map; + p->frontswap_map = frontswap_map; p->flags |= SWP_WRITEOK; nr_swap_pages += p->pages; total_swap_pages += p->pages; @@ -1544,6 +1562,7 @@ static void enable_swap_info(struct swap swap_list.head = swap_list.next = p->type; else swap_info[prev]->next = p->type; + frontswap_init(p->type); spin_unlock(&swap_lock); } @@ -1614,7 +1633,7 @@ SYSCALL_DEFINE1(swapoff, const char __us spin_unlock(&swap_lock); current->flags |= PF_OOM_ORIGIN; - err = try_to_unuse(type); + err = try_to_unuse(type, false, 0); current->flags &= ~PF_OOM_ORIGIN; if (err) { @@ -1651,9 +1670,12 @@ SYSCALL_DEFINE1(swapoff, const char __us swap_map = p->swap_map; p->swap_map = NULL; p->flags = 0; + frontswap_flush_area(type); spin_unlock(&swap_lock); mutex_unlock(&swapon_mutex); vfree(swap_map); + if (p->frontswap_map) + vfree(p->frontswap_map); /* Destroy swap account informatin */ swap_cgroup_swapoff(type); @@ -2026,6 +2048,7 @@ SYSCALL_DEFINE2(swapon, const char __use sector_t span; unsigned long maxpages; unsigned char *swap_map = NULL; + unsigned long *frontswap_map = NULL; struct page *page = NULL; struct inode *inode = NULL; @@ -2106,6 +2129,12 @@ SYSCALL_DEFINE2(swapon, const char __use error = nr_extents; goto bad_swap; } + /* frontswap enabled? set up bit-per-page map for frontswap */ + if (frontswap_enabled) { + frontswap_map = vmalloc(maxpages / sizeof(long)); + if (frontswap_map) + memset(frontswap_map, 0, maxpages / sizeof(long)); + } if (p->bdev) { if (blk_queue_nonrot(bdev_get_queue(p->bdev))) { @@ -2124,11 +2153,12 @@ SYSCALL_DEFINE2(swapon, const char __use enable_swap_info(p, prio, swap_map); printk(KERN_INFO "Adding %uk swap on %s. " - "Priority:%d extents:%d across:%lluk %s%s\n", + "Priority:%d extents:%d across:%lluk %s%s%s\n", p->pages<<(PAGE_SHIFT-10), name, p->prio, nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10), (p->flags & SWP_SOLIDSTATE) ? "SS" : "", - (p->flags & SWP_DISCARDABLE) ? "D" : ""); + (p->flags & SWP_DISCARDABLE) ? "D" : "", + (p->frontswap_map) ? "FS" : ""); mutex_unlock(&swapon_mutex); atomic_inc(&proc_poll_event); @@ -2319,6 +2349,10 @@ int valid_swaphandles(swp_entry_t entry, base++; spin_lock(&swap_lock); + if (frontswap_test(si, target)) { + spin_unlock(&swap_lock); + return 0; + } if (end > si->max) /* don't go beyond end of map */ end = si->max; @@ -2329,6 +2363,9 @@ int valid_swaphandles(swp_entry_t entry, break; if (swap_count(si->swap_map[toff]) == SWAP_MAP_BAD) break; + /* Don't read in frontswap pages */ + if (frontswap_test(si, toff)) + break; } /* Count contiguous allocated slots below our target */ for (toff = target; --toff >= base; nr_pages++) { @@ -2337,6 +2374,9 @@ int valid_swaphandles(swp_entry_t entry, break; if (swap_count(si->swap_map[toff]) == SWAP_MAP_BAD) break; + /* Don't read in frontswap pages */ + if (frontswap_test(si, toff)) + break; } spin_unlock(&swap_lock); --- linux-2.6.39/mm/page_io.c 2011-05-18 22:06:34.000000000 -0600 +++ linux-2.6.39-frontswap/mm/page_io.c 2011-05-26 15:37:25.272870914 -0600 @@ -18,6 +18,7 @@ #include #include #include +#include #include static struct bio *get_swap_bio(gfp_t gfp_flags, @@ -98,6 +99,12 @@ int swap_writepage(struct page *page, st unlock_page(page); goto out; } + if (frontswap_put_page(page) == 0) { + set_page_writeback(page); + unlock_page(page); + end_page_writeback(page); + goto out; + } bio = get_swap_bio(GFP_NOIO, page, end_swap_bio_write); if (bio == NULL) { set_page_dirty(page); @@ -122,6 +129,11 @@ int swap_readpage(struct page *page) VM_BUG_ON(!PageLocked(page)); VM_BUG_ON(PageUptodate(page)); + if (frontswap_get_page(page) == 0) { + SetPageUptodate(page); + unlock_page(page); + goto out; + } bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read); if (bio == NULL) { unlock_page(page); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/