Commit 7e1b0212 authored by Sergey Senozhatsky's avatar Sergey Senozhatsky Committed by Andrew Morton
Browse files

zram: move post-processing target allocation 

Allocate post-processing target in place_pp_slot().  This simplifies
scan_slots_for_writeback() and scan_slots_for_recompress() loops because
we don't need to track pps pointer state anymore.  Previously we have to
explicitly NULL the point if it has been added to a post-processing bucket
or re-use previously allocated pointer otherwise and make sure we don't
leak the memory in the end.

We are also fine doing GFP_NOIO allocation, as post-processing can be
called under memory pressure so we better pick as many slots as we can as
soon as we can and start post-processing them, possibly saving the memory.
Allocation failure there is not fatal, we will post-process whatever we
put into the buckets on previous iterations.

Link: https://lkml.kernel.org/r/20250303022425.285971-12-senozhatsky@chromium.org


Signed-off-by: default avatarSergey Senozhatsky <senozhatsky@chromium.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Yosry Ahmed <yosry.ahmed@linux.dev>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent b0624f0b

drivers/block/zram/zram_drv.c

+22 −28
Original line number Diff line number Diff line
@@ -295,15 +295,24 @@ static void release_pp_ctl(struct zram *zram, struct zram_pp_ctl *ctl) 
	kfree(ctl);

}



static void place_pp_slot(struct zram *zram, struct zram_pp_ctl *ctl,

			  struct zram_pp_slot *pps)

static bool place_pp_slot(struct zram *zram, struct zram_pp_ctl *ctl,

			  u32 index)

{

	u32 idx;

	struct zram_pp_slot *pps;

	u32 bid;



	pps = kmalloc(sizeof(*pps), GFP_NOIO | __GFP_NOWARN);

	if (!pps)

		return false;



	idx = zram_get_obj_size(zram, pps->index) / PP_BUCKET_SIZE_RANGE;

	list_add(&pps->entry, &ctl->pp_buckets[idx]);

	INIT_LIST_HEAD(&pps->entry);

	pps->index = index;



	bid = zram_get_obj_size(zram, pps->index) / PP_BUCKET_SIZE_RANGE;

	list_add(&pps->entry, &ctl->pp_buckets[bid]);



	zram_set_flag(zram, pps->index, ZRAM_PP_SLOT);

	return true;

}



static struct zram_pp_slot *select_pp_slot(struct zram_pp_ctl *ctl)
@@ -737,15 +746,8 @@ static int scan_slots_for_writeback(struct zram *zram, u32 mode, 
				    unsigned long index,

				    struct zram_pp_ctl *ctl)

{

	struct zram_pp_slot *pps = NULL;



	for (; nr_pages != 0; index++, nr_pages--) {

		if (!pps)

			pps = kmalloc(sizeof(*pps), GFP_KERNEL);

		if (!pps)

			return -ENOMEM;



		INIT_LIST_HEAD(&pps->entry);

		bool ok = true;



		zram_slot_lock(zram, index);

		if (!zram_allocated(zram, index))
@@ -765,14 +767,13 @@ static int scan_slots_for_writeback(struct zram *zram, u32 mode, 
		    !zram_test_flag(zram, index, ZRAM_INCOMPRESSIBLE))

			goto next;



		pps->index = index;

		place_pp_slot(zram, ctl, pps);

		pps = NULL;

		ok = place_pp_slot(zram, ctl, index);

next:

		zram_slot_unlock(zram, index);

		if (!ok)

			break;

	}



	kfree(pps);

	return 0;

}
@@ -1827,16 +1828,10 @@ static int scan_slots_for_recompress(struct zram *zram, u32 mode, u32 prio_max, 
				     struct zram_pp_ctl *ctl)

{

	unsigned long nr_pages = zram->disksize >> PAGE_SHIFT;

	struct zram_pp_slot *pps = NULL;

	unsigned long index;



	for (index = 0; index < nr_pages; index++) {

		if (!pps)

			pps = kmalloc(sizeof(*pps), GFP_KERNEL);

		if (!pps)

			return -ENOMEM;



		INIT_LIST_HEAD(&pps->entry);

		bool ok = true;



		zram_slot_lock(zram, index);

		if (!zram_allocated(zram, index))
@@ -1859,14 +1854,13 @@ static int scan_slots_for_recompress(struct zram *zram, u32 mode, u32 prio_max, 
		if (zram_get_priority(zram, index) + 1 >= prio_max)

			goto next;



		pps->index = index;

		place_pp_slot(zram, ctl, pps);

		pps = NULL;

		ok = place_pp_slot(zram, ctl, index);

next:

		zram_slot_unlock(zram, index);

		if (!ok)

			break;

	}



	kfree(pps);

	return 0;

}