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Date: Thu, 21 Feb 2013 15:33:59 +0900 From: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com> To: Ming Lei <ming.lei@...onical.com> CC: Andrew Morton <akpm@...ux-foundation.org>, <linux-kernel@...r.kernel.org>, Jens Axboe <axboe@...nel.dk> Subject: Re: [PATCH 2/2] block: partition: optimize memory allocation in check_partition 2013/02/21 14:22, Ming Lei wrote: > Currently, sizeof(struct parsed_partitions) may be 64KB in 32bit arch, > so it is easy to trigger page allocation failure by check_partition, > especially in hotplug block device situation(such as, USB mass storage, > MMC card, ...), and Felipe Balbi has observed the failure. > > This patch does below optimizations on the allocation of struct > parsed_partitions to try to address the issue: > > - make parsed_partitions.parts as pointer so that the pointed memory > can fit in 32KB buffer, then approximate 32KB memory can be saved > > - vmalloc the buffer pointed by parsed_partitions.parts because > 32KB is still a bit big for kmalloc > > - given that many devices have the partition count limit, so only > allocate disk_max_parts() partitions instead of 256 partitions always > > Reported-by: Felipe Balbi <balbi@...com> > Signed-off-by: Ming Lei <ming.lei@...onical.com> > --- Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com> Thanks, Yasuaki Ishimatsu > block/partition-generic.c | 4 ++-- > block/partitions/check.c | 37 ++++++++++++++++++++++++++++++++----- > block/partitions/check.h | 4 +++- > 3 files changed, 37 insertions(+), 8 deletions(-) > > diff --git a/block/partition-generic.c b/block/partition-generic.c > index 1cb4dec..789cdea 100644 > --- a/block/partition-generic.c > +++ b/block/partition-generic.c > @@ -418,7 +418,7 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev) > int p, highest, res; > rescan: > if (state && !IS_ERR(state)) { > - kfree(state); > + free_partitions(state); > state = NULL; > } > > @@ -525,7 +525,7 @@ rescan: > md_autodetect_dev(part_to_dev(part)->devt); > #endif > } > - kfree(state); > + free_partitions(state); > return 0; > } > > diff --git a/block/partitions/check.c b/block/partitions/check.c > index bc90867..19ba207 100644 > --- a/block/partitions/check.c > +++ b/block/partitions/check.c > @@ -14,6 +14,7 @@ > */ > > #include <linux/slab.h> > +#include <linux/vmalloc.h> > #include <linux/ctype.h> > #include <linux/genhd.h> > > @@ -106,18 +107,45 @@ static int (*check_part[])(struct parsed_partitions *) = { > NULL > }; > > +static struct parsed_partitions *allocate_partitions(struct gendisk *hd) > +{ > + struct parsed_partitions *state; > + int nr; > + > + state = kzalloc(sizeof(*state), GFP_KERNEL); > + if (!state) > + return NULL; > + > + nr = disk_max_parts(hd); > + state->parts = vzalloc(nr * sizeof(state->parts[0])); > + if (!state->parts) { > + kfree(state); > + return NULL; > + } > + > + state->limit = nr; > + > + return state; > +} > + > +void free_partitions(struct parsed_partitions *state) > +{ > + vfree(state->parts); > + kfree(state); > +} > + > struct parsed_partitions * > check_partition(struct gendisk *hd, struct block_device *bdev) > { > struct parsed_partitions *state; > int i, res, err; > > - state = kzalloc(sizeof(struct parsed_partitions), GFP_KERNEL); > + state = allocate_partitions(hd); > if (!state) > return NULL; > state->pp_buf = (char *)__get_free_page(GFP_KERNEL); > if (!state->pp_buf) { > - kfree(state); > + free_partitions(state); > return NULL; > } > state->pp_buf[0] = '\0'; > @@ -128,10 +156,9 @@ check_partition(struct gendisk *hd, struct block_device *bdev) > if (isdigit(state->name[strlen(state->name)-1])) > sprintf(state->name, "p"); > > - state->limit = disk_max_parts(hd); > i = res = err = 0; > while (!res && check_part[i]) { > - memset(&state->parts, 0, sizeof(state->parts)); > + memset(state->parts, 0, state->limit * sizeof(state->parts[0])); > res = check_part[i++](state); > if (res < 0) { > /* We have hit an I/O error which we don't report now. > @@ -161,6 +188,6 @@ check_partition(struct gendisk *hd, struct block_device *bdev) > printk(KERN_INFO "%s", state->pp_buf); > > free_page((unsigned long)state->pp_buf); > - kfree(state); > + free_partitions(state); > return ERR_PTR(res); > } > diff --git a/block/partitions/check.h b/block/partitions/check.h > index 52b1003..eade17e 100644 > --- a/block/partitions/check.h > +++ b/block/partitions/check.h > @@ -15,13 +15,15 @@ struct parsed_partitions { > int flags; > bool has_info; > struct partition_meta_info info; > - } parts[DISK_MAX_PARTS]; > + } *parts; > int next; > int limit; > bool access_beyond_eod; > char *pp_buf; > }; > > +void free_partitions(struct parsed_partitions *state); > + > struct parsed_partitions * > check_partition(struct gendisk *, struct block_device *); > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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