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 75932DDA0 for ; Tue, 20 Aug 2024 00:58:01 +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=1724115481; cv=none; b=HsRm1pvm9xuE+6qG2fie5A+v39AEMXw/uowmENN0MMQ4/Pfu0cTQiuP0uHIA9KOlYs4zPwyXzCYIAGXYmHj5DyOiV8Z7GVGrHYuAVfmWq7+DTfc0AwdTPitTx5PZjkU9a/C/5lLKbygi+99ZbdmxuPzHz3shwSd7wWYowWWIXn4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724115481; c=relaxed/simple; bh=Kjh4qs9KP0iH7jSRrKnLAbAG2/0vRUYeOiIFEfvBnGs=; h=Date:To:From:Subject:Message-Id; b=YQpTqLJQsOQ8J4HlUHJWKrxgd1Ta7OS2lVE7ewxLA4AbLFPu3gQPfji5ZEarNRFuy8x0/dYMnZv8Tc2es77PDlGJoDUF0X+FMsILdFT2xB0MUIi1tXu6cmUdAWCy3pyGGBZijxmTF/Tyx26afb/2OGQKNDSsCXdMusxazqlnf1w= 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=zI6d48kq; 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="zI6d48kq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36126C32782; Tue, 20 Aug 2024 00:58:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1724115481; bh=Kjh4qs9KP0iH7jSRrKnLAbAG2/0vRUYeOiIFEfvBnGs=; h=Date:To:From:Subject:From; b=zI6d48kqRBIWB3BrGwIwqkPkzb4ucb207AsZRbJ+xDXPqbqYGWPg9MOKDCJCMTWXt fSdsZ9XhXtmh/THAZk3mkFrFvzePSxSdGfUAQER6ZoY9xjIa73/bfDLsXHF2rV9ww8 p+NaBPMJ/vcsXO0FSuskMEig6dG0vCDv1fMPxiAg= Date: Mon, 19 Aug 2024 17:58:00 -0700 To: mm-commits@vger.kernel.org,vbabka@suse.cz,roman.gushchin@linux.dev,rientjes@google.com,penberg@kernel.org,iamjoonsoo.kim@lge.com,cl@linux.com,42.hyeyoo@gmail.com,dakr@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-krealloc-clarify-valid-usage-of-__gfp_zero.patch added to mm-unstable branch Message-Id: <20240820005801.36126C32782@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm: krealloc: clarify valid usage of __GFP_ZERO has been added to the -mm mm-unstable branch. Its filename is mm-krealloc-clarify-valid-usage-of-__gfp_zero.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-krealloc-clarify-valid-usage-of-__gfp_zero.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: Danilo Krummrich Subject: mm: krealloc: clarify valid usage of __GFP_ZERO Date: Tue, 13 Aug 2024 00:34:35 +0200 Properly document that if __GFP_ZERO logic is requested, callers must ensure that, starting with the initial memory allocation, every subsequent call to this API for the same memory allocation is flagged with __GFP_ZERO. Otherwise, it is possible that __GFP_ZERO is not fully honored by this API. Link: https://lkml.kernel.org/r/20240812223707.32049-2-dakr@kernel.org Signed-off-by: Danilo Krummrich Acked-by: David Rientjes Cc: Christoph Lameter Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim Cc: Pekka Enberg Cc: Roman Gushchin Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- include/linux/slab.h | 10 ++++++++++ mm/slab_common.c | 20 ++++++++++++++++++-- 2 files changed, 28 insertions(+), 2 deletions(-) --- a/include/linux/slab.h~mm-krealloc-clarify-valid-usage-of-__gfp_zero +++ a/include/linux/slab.h @@ -733,6 +733,16 @@ static inline __alloc_size(1, 2) void *k * @new_n: new number of elements to alloc * @new_size: new size of a single member of the array * @flags: the type of memory to allocate (see kmalloc) + * + * If __GFP_ZERO logic is requested, callers must ensure that, starting with the + * initial memory allocation, every subsequent call to this API for the same + * memory allocation is flagged with __GFP_ZERO. Otherwise, it is possible that + * __GFP_ZERO is not fully honored by this API. + * + * See krealloc_noprof() for further details. + * + * In any case, the contents of the object pointed to are preserved up to the + * lesser of the new and old sizes. */ static inline __realloc_size(2, 3) void * __must_check krealloc_array_noprof(void *p, size_t new_n, --- a/mm/slab_common.c~mm-krealloc-clarify-valid-usage-of-__gfp_zero +++ a/mm/slab_common.c @@ -1301,11 +1301,27 @@ __do_krealloc(const void *p, size_t new_ * @new_size: how many bytes of memory are required. * @flags: the type of memory to allocate. * - * The contents of the object pointed to are preserved up to the - * lesser of the new and old sizes (__GFP_ZERO flag is effectively ignored). * If @p is %NULL, krealloc() behaves exactly like kmalloc(). If @new_size * is 0 and @p is not a %NULL pointer, the object pointed to is freed. * + * If __GFP_ZERO logic is requested, callers must ensure that, starting with the + * initial memory allocation, every subsequent call to this API for the same + * memory allocation is flagged with __GFP_ZERO. Otherwise, it is possible that + * __GFP_ZERO is not fully honored by this API. + * + * This is the case, since krealloc() only knows about the bucket size of an + * allocation (but not the exact size it was allocated with) and hence + * implements the following semantics for shrinking and growing buffers with + * __GFP_ZERO. + * + * new bucket + * 0 size size + * |--------|----------------| + * | keep | zero | + * + * In any case, the contents of the object pointed to are preserved up to the + * lesser of the new and old sizes. + * * Return: pointer to the allocated memory or %NULL in case of error */ void *krealloc_noprof(const void *p, size_t new_size, gfp_t flags) _ Patches currently in -mm which might be from dakr@kernel.org are mm-vmalloc-implement-vrealloc.patch mm-vmalloc-implement-vrealloc-fix.patch mm-vmalloc-implement-vrealloc-fix-2.patch mm-vmalloc-implement-vrealloc-fix-3.patch mm-vmalloc-implement-vrealloc-fix-4.patch mm-kvmalloc-align-kvrealloc-with-krealloc.patch mm-kvmalloc-align-kvrealloc-with-krealloc-fix.patch mm-kvmalloc-align-kvrealloc-with-krealloc-fix-2.patch mm-kvmalloc-align-kvrealloc-with-krealloc-fix-3.patch mm-krealloc-consider-spare-memory-for-__gfp_zero.patch mm-krealloc-clarify-valid-usage-of-__gfp_zero.patch