The patch titled
Subject: zram: factor out different page types read
has been added to the -mm mm-unstable branch. Its filename is
zram-factor-out-different-page-types-read.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-factor-out-different-page-types-read.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Subject: zram: factor out different page types read
Date: Wed, 18 Dec 2024 15:34:22 +0900
Similarly to write, split the page read code into ZRAM_HUGE read,
ZRAM_SAME read and compressed page read to simplify the code.
Link: https://lkml.kernel.org/r/20241218063513.297475-6-senozhatsky@xxxxxxxxxxxx
Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 85 +++++++++++++++++++-------------
1 file changed, 52 insertions(+), 33 deletions(-)
--- a/drivers/block/zram/zram_drv.c~zram-factor-out-different-page-types-read
+++ a/drivers/block/zram/zram_drv.c
@@ -1530,54 +1530,73 @@ out:
zram_set_obj_size(zram, index, 0);
}
-/*
- * Reads (decompresses if needed) a page from zspool (zsmalloc).
- * Corresponding ZRAM slot should be locked.
- */
-static int zram_read_from_zspool(struct zram *zram, struct page *page,
+static int read_same_filled_page(struct zram *zram, struct page *page,
u32 index)
{
- struct zcomp_strm *zstrm;
+ void *mem;
+
+ mem = kmap_local_page(page);
+ zram_fill_page(mem, PAGE_SIZE, zram_get_handle(zram, index));
+ kunmap_local(mem);
+ return 0;
+}
+
+static int read_incompressible_page(struct zram *zram, struct page *page,
+ u32 index)
+{
unsigned long handle;
- unsigned int size;
void *src, *dst;
- u32 prio;
- int ret;
handle = zram_get_handle(zram, index);
- if (!handle || zram_test_flag(zram, index, ZRAM_SAME)) {
- void *mem;
+ src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
+ dst = kmap_local_page(page);
+ copy_page(dst, src);
+ kunmap_local(dst);
+ zs_unmap_object(zram->mem_pool, handle);
- mem = kmap_local_page(page);
- zram_fill_page(mem, PAGE_SIZE, handle);
- kunmap_local(mem);
- return 0;
- }
+ return 0;
+}
- size = zram_get_obj_size(zram, index);
+static int read_compressed_page(struct zram *zram, struct page *page, u32 index)
+{
+ struct zcomp_strm *zstrm;
+ unsigned long handle;
+ unsigned int size;
+ void *src, *dst;
+ int ret, prio;
- if (size != PAGE_SIZE) {
- prio = zram_get_priority(zram, index);
- zstrm = zcomp_stream_get(zram->comps[prio]);
- }
+ handle = zram_get_handle(zram, index);
+ size = zram_get_obj_size(zram, index);
+ prio = zram_get_priority(zram, index);
+ zstrm = zcomp_stream_get(zram->comps[prio]);
src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
- if (size == PAGE_SIZE) {
- dst = kmap_local_page(page);
- copy_page(dst, src);
- kunmap_local(dst);
- ret = 0;
- } else {
- dst = kmap_local_page(page);
- ret = zcomp_decompress(zram->comps[prio], zstrm,
- src, size, dst);
- kunmap_local(dst);
- zcomp_stream_put(zram->comps[prio]);
- }
+ dst = kmap_local_page(page);
+ ret = zcomp_decompress(zram->comps[prio], zstrm, src, size, dst);
+ kunmap_local(dst);
zs_unmap_object(zram->mem_pool, handle);
+ zcomp_stream_put(zram->comps[prio]);
+
return ret;
}
+/*
+ * Reads (decompresses if needed) a page from zspool (zsmalloc).
+ * Corresponding ZRAM slot should be locked.
+ */
+static int zram_read_from_zspool(struct zram *zram, struct page *page,
+ u32 index)
+{
+ if (zram_test_flag(zram, index, ZRAM_SAME) ||
+ !zram_get_handle(zram, index))
+ return read_same_filled_page(zram, page, index);
+
+ if (!zram_test_flag(zram, index, ZRAM_HUGE))
+ return read_compressed_page(zram, page, index);
+ else
+ return read_incompressible_page(zram, page, index);
+}
+
static int zram_read_page(struct zram *zram, struct page *page, u32 index,
struct bio *parent)
{
_
Patches currently in -mm which might be from senozhatsky@xxxxxxxxxxxx are
zram-free-slot-memory-early-during-write.patch
zram-remove-entry-element-member.patch
zram-factor-out-zram_same-write.patch
zram-factor-out-zram_huge-write.patch
zram-factor-out-different-page-types-read.patch
zram-use-zram_read_from_zspool-in-writeback.patch
zram-cond_resched-in-writeback-loop.patch
