The patch titled
Subject: zram: switch to new zsmalloc object mapping API
has been added to the -mm mm-unstable branch. Its filename is
zram-switch-to-new-zsmalloc-object-mapping-api.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-switch-to-new-zsmalloc-object-mapping-api.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Subject: zram: switch to new zsmalloc object mapping API
Date: Fri, 14 Feb 2025 13:50:25 +0900
Use new read/write zsmalloc object API. For cases when RO mapped object
spans two physical pages (requires temp buffer) compression streams now
carry around one extra physical page.
Link: https://lkml.kernel.org/r/20250214045208.1388854-14-senozhatsky@xxxxxxxxxxxx
Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Hillf Danton <hdanton@xxxxxxxx>
Cc: Kairui Song <ryncsn@xxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Yosry Ahmed <yosry.ahmed@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zcomp.c | 4 +++-
drivers/block/zram/zcomp.h | 2 ++
drivers/block/zram/zram_drv.c | 28 ++++++++++------------------
3 files changed, 15 insertions(+), 19 deletions(-)
--- a/drivers/block/zram/zcomp.c~zram-switch-to-new-zsmalloc-object-mapping-api
+++ a/drivers/block/zram/zcomp.c
@@ -45,6 +45,7 @@ static const struct zcomp_ops *backends[
static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm)
{
comp->ops->destroy_ctx(&zstrm->ctx);
+ vfree(zstrm->local_copy);
vfree(zstrm->buffer);
zstrm->buffer = NULL;
}
@@ -57,12 +58,13 @@ static int zcomp_strm_init(struct zcomp
if (ret)
return ret;
+ zstrm->local_copy = vzalloc(PAGE_SIZE);
/*
* allocate 2 pages. 1 for compressed data, plus 1 extra for the
* case when compressed size is larger than the original one
*/
zstrm->buffer = vzalloc(2 * PAGE_SIZE);
- if (!zstrm->buffer) {
+ if (!zstrm->buffer || !zstrm->local_copy) {
zcomp_strm_free(comp, zstrm);
return -ENOMEM;
}
--- a/drivers/block/zram/zcomp.h~zram-switch-to-new-zsmalloc-object-mapping-api
+++ a/drivers/block/zram/zcomp.h
@@ -34,6 +34,8 @@ struct zcomp_strm {
struct mutex lock;
/* compression buffer */
void *buffer;
+ /* local copy of handle memory */
+ void *local_copy;
struct zcomp_ctx ctx;
};
--- a/drivers/block/zram/zram_drv.c~zram-switch-to-new-zsmalloc-object-mapping-api
+++ a/drivers/block/zram/zram_drv.c
@@ -1603,11 +1603,11 @@ static int read_incompressible_page(stru
void *src, *dst;
handle = zram_get_handle(zram, index);
- src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
+ src = zs_obj_read_begin(zram->mem_pool, handle, NULL);
dst = kmap_local_page(page);
copy_page(dst, src);
kunmap_local(dst);
- zs_unmap_object(zram->mem_pool, handle);
+ zs_obj_read_end(zram->mem_pool, handle, src);
return 0;
}
@@ -1625,11 +1625,11 @@ static int read_compressed_page(struct z
prio = zram_get_priority(zram, index);
zstrm = zcomp_stream_get(zram->comps[prio]);
- src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
+ src = zs_obj_read_begin(zram->mem_pool, handle, zstrm->local_copy);
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);
+ zs_obj_read_end(zram->mem_pool, handle, src);
zcomp_stream_put(zstrm);
return ret;
@@ -1725,7 +1725,7 @@ static int write_incompressible_page(str
u32 index)
{
unsigned long handle;
- void *src, *dst;
+ void *src;
/*
* This function is called from preemptible context so we don't need
@@ -1742,11 +1742,9 @@ static int write_incompressible_page(str
return -ENOMEM;
}
- dst = zs_map_object(zram->mem_pool, handle, ZS_MM_WO);
src = kmap_local_page(page);
- memcpy(dst, src, PAGE_SIZE);
+ zs_obj_write(zram->mem_pool, handle, src, PAGE_SIZE);
kunmap_local(src);
- zs_unmap_object(zram->mem_pool, handle);
zram_slot_lock(zram, index);
zram_set_flag(zram, index, ZRAM_HUGE);
@@ -1767,7 +1765,7 @@ static int zram_write_page(struct zram *
int ret = 0;
unsigned long handle;
unsigned int comp_len;
- void *dst, *mem;
+ void *mem;
struct zcomp_strm *zstrm;
unsigned long element;
bool same_filled;
@@ -1813,11 +1811,8 @@ static int zram_write_page(struct zram *
return -ENOMEM;
}
- dst = zs_map_object(zram->mem_pool, handle, ZS_MM_WO);
-
- memcpy(dst, zstrm->buffer, comp_len);
+ zs_obj_write(zram->mem_pool, handle, zstrm->buffer, comp_len);
zcomp_stream_put(zstrm);
- zs_unmap_object(zram->mem_pool, handle);
zram_slot_lock(zram, index);
zram_set_handle(zram, index, handle);
@@ -1929,7 +1924,7 @@ static int recompress_slot(struct zram *
unsigned int comp_len_new;
unsigned int class_index_old;
unsigned int class_index_new;
- void *src, *dst;
+ void *src;
int ret = 0;
handle_old = zram_get_handle(zram, index);
@@ -2039,12 +2034,9 @@ static int recompress_slot(struct zram *
return PTR_ERR((void *)handle_new);
}
- dst = zs_map_object(zram->mem_pool, handle_new, ZS_MM_WO);
- memcpy(dst, zstrm->buffer, comp_len_new);
+ zs_obj_write(zram->mem_pool, handle_new, zstrm->buffer, comp_len_new);
zcomp_stream_put(zstrm);
- zs_unmap_object(zram->mem_pool, handle_new);
-
zram_free_page(zram, index);
zram_set_handle(zram, index, handle_new);
zram_set_obj_size(zram, index, comp_len_new);
_
Patches currently in -mm which might be from senozhatsky@xxxxxxxxxxxx are
zram-sleepable-entry-locking.patch
zram-permit-preemption-with-active-compression-stream.patch
zram-remove-unused-crypto-include.patch
zram-remove-max_comp_streams-device-attr.patch
zram-remove-two-staged-handle-allocation.patch
zram-remove-writestall-zram_stats-member.patch
zram-limit-max-recompress-prio-to-num_active_comps.patch
zram-filter-out-recomp-targets-based-on-priority.patch
zram-rework-recompression-loop.patch
zsmalloc-rename-pool-lock.patch
zsmalloc-make-zspage-lock-preemptible.patch
zsmalloc-introduce-new-object-mapping-api.patch
zram-switch-to-new-zsmalloc-object-mapping-api.patch
zram-permit-reclaim-in-zstd-custom-allocator.patch
zram-do-not-leak-page-on-recompress_store-error-path.patch
zram-do-not-leak-page-on-writeback_store-error-path.patch
zram-add-might_sleep-to-zcomp-api.patch
