Commit e947ba0b authored by Chengming Zhou's avatar Chengming Zhou Committed by Andrew Morton
Browse files

mm/zswap: cleanup zswap_writeback_entry() 

Also after the common decompress part goes to __zswap_load(), we can
cleanup the zswap_writeback_entry() a little.

Link: https://lkml.kernel.org/r/20231213-zswap-dstmem-v5-4-9382162bbf05@bytedance.com


Signed-off-by: default avatarChengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: default avatarYosry Ahmed <yosryahmed@google.com>
Reviewed-by: default avatarNhat Pham <nphamcs@gmail.com>
Acked-by: Chris Li <chrisl@kernel.org> (Google)
Cc: Barry Song <21cnbao@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 66447fd0

mm/zswap.c

+10 −19
Original line number Diff line number Diff line
@@ -1434,7 +1434,6 @@ static int zswap_writeback_entry(struct zswap_entry *entry, 
	struct page *page;

	struct mempolicy *mpol;

	bool page_was_allocated;

	int ret;

	struct writeback_control wbc = {

		.sync_mode = WB_SYNC_NONE,

	};
@@ -1443,16 +1442,17 @@ static int zswap_writeback_entry(struct zswap_entry *entry, 
	mpol = get_task_policy(current);

	page = __read_swap_cache_async(swpentry, GFP_KERNEL, mpol,

				NO_INTERLEAVE_INDEX, &page_was_allocated, true);

	if (!page) {

		ret = -ENOMEM;

		goto fail;

	}

	if (!page)

		return -ENOMEM;



	/* Found an existing page, we raced with load/swapin */

	/*

	 * Found an existing page, we raced with load/swapin. We generally

	 * writeback cold pages from zswap, and swapin means the page just

	 * became hot. Skip this page and let the caller find another one.

	 */

	if (!page_was_allocated) {

		put_page(page);

		ret = -EEXIST;

		goto fail;

		return -EEXIST;

	}



	/*
@@ -1466,8 +1466,7 @@ static int zswap_writeback_entry(struct zswap_entry *entry, 
	if (zswap_rb_search(&tree->rbroot, swp_offset(entry->swpentry)) != entry) {

		spin_unlock(&tree->lock);

		delete_from_swap_cache(page_folio(page));

		ret = -ENOMEM;

		goto fail;

		return -ENOMEM;

	}

	spin_unlock(&tree->lock);
@@ -1483,15 +1482,7 @@ static int zswap_writeback_entry(struct zswap_entry *entry, 
	__swap_writepage(page, &wbc);

	put_page(page);



	return ret;



fail:

	/*

	 * If we get here because the page is already in swapcache, a

	 * load may be happening concurrently. It is safe and okay to

	 * not free the entry. It is also okay to return !0.

	 */

	return ret;

	return 0;

}



static int zswap_is_page_same_filled(void *ptr, unsigned long *value)