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Commit 6c1e875c authored by Artem Bityutskiy's avatar Artem Bityutskiy
Browse files

UBI: add slab cache for ubi_scan_leb objects 



During scanning UBI allocates one struct ubi_scan_leb object for each PEB,
so it can end up allocating thousands of them. Use slab cache to reduce
memory consumption for these 48-byte objects, because currently used
'kmalloc()' ends up allocating 64 bytes per object, instead of 48.

Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent 7950d023

drivers/mtd/ubi/build.c

+2 −0
Original line number Diff line number Diff line
@@ -923,6 +923,8 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset) 
	spin_lock_init(&ubi->volumes_lock);



	ubi_msg("attaching mtd%d to ubi%d", mtd->index, ubi_num);

	dbg_msg("sizeof(struct ubi_scan_leb) %zu", sizeof(struct ubi_scan_leb));

	dbg_msg("sizeof(struct ubi_wl_entry) %zu", sizeof(struct ubi_wl_entry));



	err = io_init(ubi);

	if (err)

drivers/mtd/ubi/scan.c

+21 −11
Original line number Diff line number Diff line
@@ -115,7 +115,7 @@ static int add_to_list(struct ubi_scan_info *si, int pnum, int ec, int to_head, 
	} else

		BUG();



	seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);

	seb = kmem_cache_alloc(si->scan_leb_slab, GFP_KERNEL);

	if (!seb)

		return -ENOMEM;
@@ -144,7 +144,7 @@ static int add_corrupted(struct ubi_scan_info *si, int pnum, int ec) 


	dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec);



	seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);

	seb = kmem_cache_alloc(si->scan_leb_slab, GFP_KERNEL);

	if (!seb)

		return -ENOMEM;
@@ -553,7 +553,7 @@ int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si, 
	if (err)

		return err;



	seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);

	seb = kmem_cache_alloc(si->scan_leb_slab, GFP_KERNEL);

	if (!seb)

		return -ENOMEM;
@@ -1152,9 +1152,15 @@ struct ubi_scan_info *ubi_scan(struct ubi_device *ubi) 
	si->volumes = RB_ROOT;



	err = -ENOMEM;

	si->scan_leb_slab = kmem_cache_create("ubi_scan_leb_slab",

					      sizeof(struct ubi_scan_leb),

					      0, 0, NULL);

	if (!si->scan_leb_slab)

		goto out_si;



	ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);

	if (!ech)

		goto out_si;

		goto out_slab;



	vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);

	if (!vidh)
@@ -1215,6 +1221,8 @@ struct ubi_scan_info *ubi_scan(struct ubi_device *ubi) 
	ubi_free_vid_hdr(ubi, vidh);

out_ech:

	kfree(ech);

out_slab:

	kmem_cache_destroy(si->scan_leb_slab);

out_si:

	ubi_scan_destroy_si(si);

	return ERR_PTR(err);
@@ -1223,11 +1231,12 @@ struct ubi_scan_info *ubi_scan(struct ubi_device *ubi) 
/**

 * destroy_sv - free the scanning volume information

 * @sv: scanning volume information

 * @si: scanning information

 *

 * This function destroys the volume RB-tree (@sv->root) and the scanning

 * volume information.

 */

static void destroy_sv(struct ubi_scan_volume *sv)

static void destroy_sv(struct ubi_scan_info *si, struct ubi_scan_volume *sv)

{

	struct ubi_scan_leb *seb;

	struct rb_node *this = sv->root.rb_node;
@@ -1247,7 +1256,7 @@ static void destroy_sv(struct ubi_scan_volume *sv) 
					this->rb_right = NULL;

			}



			kfree(seb);

			kmem_cache_free(si->scan_leb_slab, seb);

		}

	}

	kfree(sv);
@@ -1265,19 +1274,19 @@ void ubi_scan_destroy_si(struct ubi_scan_info *si) 


	list_for_each_entry_safe(seb, seb_tmp, &si->alien, u.list) {

		list_del(&seb->u.list);

		kfree(seb);

		kmem_cache_free(si->scan_leb_slab, seb);

	}

	list_for_each_entry_safe(seb, seb_tmp, &si->erase, u.list) {

		list_del(&seb->u.list);

		kfree(seb);

		kmem_cache_free(si->scan_leb_slab, seb);

	}

	list_for_each_entry_safe(seb, seb_tmp, &si->corr, u.list) {

		list_del(&seb->u.list);

		kfree(seb);

		kmem_cache_free(si->scan_leb_slab, seb);

	}

	list_for_each_entry_safe(seb, seb_tmp, &si->free, u.list) {

		list_del(&seb->u.list);

		kfree(seb);

		kmem_cache_free(si->scan_leb_slab, seb);

	}



	/* Destroy the volume RB-tree */
@@ -1298,10 +1307,11 @@ void ubi_scan_destroy_si(struct ubi_scan_info *si) 
					rb->rb_right = NULL;

			}



			destroy_sv(sv);

			destroy_sv(si, sv);

		}

	}



	kmem_cache_destroy(si->scan_leb_slab);

	kfree(si);

}

drivers/mtd/ubi/scan.h

+2 −0
Original line number Diff line number Diff line
@@ -109,6 +109,7 @@ struct ubi_scan_volume { 
 * @mean_ec: mean erase counter value

 * @ec_sum: a temporary variable used when calculating @mean_ec

 * @ec_count: a temporary variable used when calculating @mean_ec

 * @scan_leb_slab: slab cache for &struct ubi_scan_leb objects

 *

 * This data structure contains the result of scanning and may be used by other

 * UBI sub-systems to build final UBI data structures, further error-recovery
@@ -134,6 +135,7 @@ struct ubi_scan_info { 
	int mean_ec;

	uint64_t ec_sum;

	int ec_count;

	struct kmem_cache *scan_leb_slab;

};



struct ubi_device;