From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4178F42A95 for ; Fri, 21 Feb 2025 23:42:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740181359; cv=none; b=qFDmGI0b/3ghFm6yZnydbG4DYgau1TJdF33V+5CxYRIVpUvkwG9Pzp8zuesx8Qfp+wfEdJiWeyCarQstT8cvXhUecXTsf914cqDUidUZEWLIAZzt/gIeYfDutTnAUaDz97e+aZXSvBdfRsfVBEGdR8jlPbfIxB8h1cnsuD917WU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740181359; c=relaxed/simple; bh=3IOnc5Kbwd6V/hz5naUKse18XLbXMWyKeJ31my4CE84=; h=Date:To:From:Subject:Message-Id; b=tnrkJkvt37uQlib/zbhFM0OyN8587ANln3IqvKXoarxmSaf1Ce2qjvbmzG0d7jq02EW7Dy5LwxbBQdDT0WcJQm0jgJyLxQeU9UhDcyHuw83AiinwChcjJO+UIWGS9LSQUsIosqMPKSkaXuhiCac2lJSNoOwnjX7wrY/JUw/OXow= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=Hnmpdyyk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="Hnmpdyyk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9AD53C4CED6; Fri, 21 Feb 2025 23:42:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1740181358; bh=3IOnc5Kbwd6V/hz5naUKse18XLbXMWyKeJ31my4CE84=; h=Date:To:From:Subject:From; b=HnmpdyykNNBTqMsctT/ZYXP93z/jja69RR+6mnP+JYoa4thC40UljmZ7XTDMMFhQu UL27ZwWFMZX6iIN80Hb8VjmDrtKVQMhRQgvzPxy5OeIgJYQphlj0spPjEBTBA2fmZ4 BhdbEZknwePJnvW19E8D25Ygkb95yC1dfaQf+Ang= Date: Fri, 21 Feb 2025 15:42:38 -0800 To: mm-commits@vger.kernel.org,yosry.ahmed@linux.dev,minchan@kernel.org,hdanton@sina.com,bigeasy@linutronix.de,senozhatsky@chromium.org,akpm@linux-foundation.org From: Andrew Morton Subject: + zram-remove-second-stage-of-handle-allocation.patch added to mm-unstable branch Message-Id: <20250221234238.9AD53C4CED6@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: zram: remove second stage of handle allocation has been added to the -mm mm-unstable branch. Its filename is zram-remove-second-stage-of-handle-allocation.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-remove-second-stage-of-handle-allocation.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 Subject: zram: remove second stage of handle allocation Date: Sat, 22 Feb 2025 07:25:36 +0900 Previously zram write() was atomic which required us to pass __GFP_KSWAPD_RECLAIM to zsmalloc handle allocation on a fast path and attempt a slow path allocation (with recompression) if the fast path failed. Since we are not in atomic context anymore we can permit direct reclaim during handle allocation, and hence can have a single allocation path. There is no slow path anymore so we don't unlock per-CPU stream (and don't lose compressed data) which means that there is no need to do recompression now (which should reduce CPU and battery usage). Link: https://lkml.kernel.org/r/20250221222958.2225035-6-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky Cc: Hillf Danton Cc: Minchan Kim Cc: Sebastian Andrzej Siewior Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- drivers/block/zram/zram_drv.c | 38 +++++--------------------------- 1 file changed, 6 insertions(+), 32 deletions(-) --- a/drivers/block/zram/zram_drv.c~zram-remove-second-stage-of-handle-allocation +++ a/drivers/block/zram/zram_drv.c @@ -1729,11 +1729,11 @@ static int write_incompressible_page(str static int zram_write_page(struct zram *zram, struct page *page, u32 index) { int ret = 0; - unsigned long handle = -ENOMEM; - unsigned int comp_len = 0; + unsigned long handle; + unsigned int comp_len; void *dst, *mem; struct zcomp_strm *zstrm; - unsigned long element = 0; + unsigned long element; bool same_filled; /* First, free memory allocated to this slot (if any) */ @@ -1747,7 +1747,6 @@ static int zram_write_page(struct zram * if (same_filled) return write_same_filled_page(zram, element, index); -compress_again: zstrm = zcomp_stream_get(zram->comps[ZRAM_PRIMARY_COMP]); mem = kmap_local_page(page); ret = zcomp_compress(zram->comps[ZRAM_PRIMARY_COMP], zstrm, @@ -1757,7 +1756,6 @@ compress_again: if (unlikely(ret)) { zcomp_stream_put(zstrm); pr_err("Compression failed! err=%d\n", ret); - zs_free(zram->mem_pool, handle); return ret; } @@ -1766,35 +1764,11 @@ compress_again: return write_incompressible_page(zram, page, index); } - /* - * handle allocation has 2 paths: - * a) fast path is executed with preemption disabled (for - * per-cpu streams) and has __GFP_DIRECT_RECLAIM bit clear, - * since we can't sleep; - * b) slow path enables preemption and attempts to allocate - * the page with __GFP_DIRECT_RECLAIM bit set. we have to - * put per-cpu compression stream and, thus, to re-do - * the compression once handle is allocated. - * - * if we have a 'non-null' handle here then we are coming - * from the slow path and handle has already been allocated. - */ - if (IS_ERR_VALUE(handle)) - handle = zs_malloc(zram->mem_pool, comp_len, - __GFP_KSWAPD_RECLAIM | - __GFP_NOWARN | - __GFP_HIGHMEM | - __GFP_MOVABLE); + handle = zs_malloc(zram->mem_pool, comp_len, + GFP_NOIO | __GFP_HIGHMEM | __GFP_MOVABLE); if (IS_ERR_VALUE(handle)) { zcomp_stream_put(zstrm); - atomic64_inc(&zram->stats.writestall); - handle = zs_malloc(zram->mem_pool, comp_len, - GFP_NOIO | __GFP_HIGHMEM | - __GFP_MOVABLE); - if (IS_ERR_VALUE(handle)) - return PTR_ERR((void *)handle); - - goto compress_again; + return PTR_ERR((void *)handle); } if (!zram_can_store_page(zram)) { _ Patches currently in -mm which might be from senozhatsky@chromium.org 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-second-stage-of-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 zsmalloc-zram-there-be-preemption.patch