Messages in this thread Patch in this message | | | From | Nitin Gupta <> | Subject | [PATCH 2/2] [mmotm v2] ramzswap: add handlers for various swap events | Date | Thu, 31 Dec 2009 09:38:38 +0530 |
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The SWAPON handler sets callback which frees memory associated with given swap slot, eliminating any stale data in corresponding ramzswap device.
v2: add calls to unregister all notifiers during module unload.
Signed-off-by: Nitin Gupta <ngupta@vflare.org> --- drivers/staging/ramzswap/ramzswap_drv.c | 73 +++++++++++++++++++++++++++++ drivers/staging/ramzswap/ramzswap_drv.h | 1 + drivers/staging/ramzswap/ramzswap_ioctl.h | 1 + 3 files changed, 75 insertions(+), 0 deletions(-)
diff --git a/drivers/staging/ramzswap/ramzswap_drv.c b/drivers/staging/ramzswap/ramzswap_drv.c index b839f05..fd4db0f 100644 --- a/drivers/staging/ramzswap/ramzswap_drv.c +++ b/drivers/staging/ramzswap/ramzswap_drv.c @@ -276,6 +276,7 @@ void ramzswap_ioctl_get_stats(struct ramzswap *rzs, s->failed_reads = rs->failed_reads; s->failed_writes = rs->failed_writes; s->invalid_io = rs->invalid_io; + s->notify_free = rs->notify_free; s->pages_zero = rs->pages_zero; s->good_compress_pct = good_compress_perc; @@ -1355,6 +1356,51 @@ static void create_device(struct ramzswap *rzs, int device_id) rzs->init_done = 0; } +static int ramzswap_slot_free_notify(struct notifier_block *self, + unsigned long index, void *swap_file) +{ + struct ramzswap *rzs; + + rzs = ((struct file *)swap_file)->private_data; + ramzswap_free_page(rzs, index); + stat_inc(rzs->stats.notify_free); + return 0; +} + +static struct notifier_block ramzswap_slot_free_nb = { + .notifier_call = ramzswap_slot_free_notify +}; + +static int ramzswap_swapon_notify(struct notifier_block *self, + unsigned long swap_id, void *swap_file) +{ + int ret = 0; + struct block_device *bdev; + struct file *file; + struct inode *inode; + struct ramzswap *rzs; + + /* cache ramzswap struct associated with this swap_file */ + file = (struct file *)swap_file; + inode = file->f_mapping->host; + bdev = I_BDEV(inode); + rzs = bdev->bd_disk->private_data; + file->private_data = rzs; + + ret = register_swap_event_notifier(&ramzswap_slot_free_nb, + SWAP_EVENT_SLOT_FREE, swap_id); + if (ret) + pr_err("Error registering swap free notifier\n"); + return ret; +} + +static int ramzswap_swapoff_notify(struct notifier_block *self, + unsigned long swap_id, void *swap_file) +{ + unregister_swap_event_notifier(&ramzswap_slot_free_nb, + SWAP_EVENT_SLOT_FREE, swap_id); + return 0; +} static void destroy_device(struct ramzswap *rzs) { @@ -1367,6 +1413,14 @@ static void destroy_device(struct ramzswap *rzs) blk_cleanup_queue(rzs->queue); } +static struct notifier_block ramzswap_swapon_nb = { + .notifier_call = ramzswap_swapon_notify +}; + +static struct notifier_block ramzswap_swapoff_nb = { + .notifier_call = ramzswap_swapoff_notify +}; + static int __init ramzswap_init(void) { int i, ret; @@ -1399,6 +1453,20 @@ static int __init ramzswap_init(void) for (i = 0; i < num_devices; i++) create_device(&devices[i], i); + ret = register_swap_event_notifier(&ramzswap_swapon_nb, + SWAP_EVENT_SWAPON, 0); + if (ret) { + pr_err("Error registering swapon notifier\n"); + goto out; + } + + ret = register_swap_event_notifier(&ramzswap_swapoff_nb, + SWAP_EVENT_SWAPOFF, 0); + if (ret) { + pr_err("Error registering swapoff notifier\n"); + goto out; + } + return 0; out: unregister_blkdev(ramzswap_major, "ramzswap"); @@ -1410,6 +1478,11 @@ static void __exit ramzswap_exit(void) int i; struct ramzswap *rzs; + unregister_swap_event_notifier(&ramzswap_swapon_nb, + SWAP_EVENT_SWAPON, 0); + unregister_swap_event_notifier(&ramzswap_swapoff_nb, + SWAP_EVENT_SWAPOFF, 0); + for (i = 0; i < num_devices; i++) { rzs = &devices[i]; diff --git a/drivers/staging/ramzswap/ramzswap_drv.h b/drivers/staging/ramzswap/ramzswap_drv.h index a6ea240..adc841a 100644 --- a/drivers/staging/ramzswap/ramzswap_drv.h +++ b/drivers/staging/ramzswap/ramzswap_drv.h @@ -124,6 +124,7 @@ struct ramzswap_stats { u64 failed_reads; /* can happen when memory is too low */ u64 failed_writes; /* should NEVER! happen */ u64 invalid_io; /* non-swap I/O requests */ + u64 notify_free; /* no. of swap slot free notifications */ u32 pages_zero; /* no. of zero filled pages */ u32 pages_stored; /* no. of pages currently stored */ u32 good_compress; /* % of pages with compression ratio<=50% */ diff --git a/drivers/staging/ramzswap/ramzswap_ioctl.h b/drivers/staging/ramzswap/ramzswap_ioctl.h index c713a09..ec50416 100644 --- a/drivers/staging/ramzswap/ramzswap_ioctl.h +++ b/drivers/staging/ramzswap/ramzswap_ioctl.h @@ -27,6 +27,7 @@ struct ramzswap_ioctl_stats { u64 failed_reads; /* can happen when memory is too low */ u64 failed_writes; /* should NEVER! happen */ u64 invalid_io; /* non-swap I/O requests */ + u64 notify_free; /* no. of swap slot free notifications */ u32 pages_zero; /* no. of zero filled pages */ u32 good_compress_pct; /* no. of pages with compression ratio<=50% */ u32 pages_expand_pct; /* no. of incompressible pages */ -- 1.6.2.5
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