From: Gao Xiang <gaoxiang25@huawei.com> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, <devel@driverdev.osuosl.org> Cc: <linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>, <linux-erofs@lists.ozlabs.org>, <yuchao0@huawei.com>, <miaoxie@huawei.com>, <weidu.du@huawei.com>, <hsiangkao@aol.com>, <chao@kernel.org>, Gao Xiang <gaoxiang25@huawei.com> Subject: [PATCH 13/25] staging: erofs: <linux/tagptr.h>: introduce tagged pointer Date: Thu, 26 Jul 2018 20:21:56 +0800 [thread overview] Message-ID: <1532607728-103372-14-git-send-email-gaoxiang25@huawei.com> (raw) In-Reply-To: <1532607728-103372-1-git-send-email-gaoxiang25@huawei.com> Currently kernel has scattered tagged pointer usages hacked by hand in plain code, without a unique and portable functionset to highlight the tagged pointer itself and wrap these hacked code in order to clean up all over meaningless magic masks. Therefore, this patch introduces simple generic methods to fold tags into a pointer integer. It currently supports the last n bits of the pointer for tags, which can be selected by users. In addition, it will also be used for the upcoming EROFS filesystem, which heavily uses tagged pointer approach for high performance and reducing extra memory allocation. Link: https://en.wikipedia.org/wiki/Tagged_pointer Signed-off-by: Gao Xiang <gaoxiang25@huawei.com> --- drivers/staging/erofs/include/linux/tagptr.h | 110 +++++++++++++++++++++++++++ 1 file changed, 110 insertions(+) create mode 100644 drivers/staging/erofs/include/linux/tagptr.h diff --git a/drivers/staging/erofs/include/linux/tagptr.h b/drivers/staging/erofs/include/linux/tagptr.h new file mode 100644 index 0000000..ccd106d --- /dev/null +++ b/drivers/staging/erofs/include/linux/tagptr.h @@ -0,0 +1,110 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * Tagged pointer implementation + * + * Copyright (C) 2018 Gao Xiang <gaoxiang25@huawei.com> + */ +#ifndef _LINUX_TAGPTR_H +#define _LINUX_TAGPTR_H + +#include <linux/types.h> +#include <linux/build_bug.h> + +/* + * the name of tagged pointer types are tagptr{1, 2, 3...}_t + * avoid directly using the internal structs __tagptr{1, 2, 3...} + */ +#define __MAKE_TAGPTR(n) \ +typedef struct __tagptr##n { \ + uintptr_t v; \ +} tagptr##n##_t; + +__MAKE_TAGPTR(1) +__MAKE_TAGPTR(2) +__MAKE_TAGPTR(3) +__MAKE_TAGPTR(4) + +#undef __MAKE_TAGPTR + +extern void __compiletime_error("bad tagptr tags") + __bad_tagptr_tags(void); + +extern void __compiletime_error("bad tagptr type") + __bad_tagptr_type(void); + +/* fix the broken usage of "#define tagptr2_t tagptr3_t" by users */ +#define __tagptr_mask_1(ptr, n) \ + __builtin_types_compatible_p(typeof(ptr), struct __tagptr##n) ? \ + (1UL << (n)) - 1 : + +#define __tagptr_mask(ptr) (\ + __tagptr_mask_1(ptr, 1) ( \ + __tagptr_mask_1(ptr, 2) ( \ + __tagptr_mask_1(ptr, 3) ( \ + __tagptr_mask_1(ptr, 4) ( \ + __bad_tagptr_type(), 0))))) + +/* generate a tagged pointer from a raw value */ +#define tagptr_init(type, val) \ + ((typeof(type)){ .v = (uintptr_t)(val) }) + +/* + * directly cast a tagged pointer to the native pointer type, which + * could be used for backward compatibility of existing code. + */ +#define tagptr_cast_ptr(tptr) ((void *)(tptr).v) + +/* encode tagged pointers */ +#define tagptr_fold(type, ptr, _tags) ({ \ + const typeof(_tags) tags = (_tags); \ + if (__builtin_constant_p(tags) && (tags & ~__tagptr_mask(type))) \ + __bad_tagptr_tags(); \ +tagptr_init(type, (uintptr_t)(ptr) | tags); }) + +/* decode tagged pointers */ +#define tagptr_unfold_ptr(tptr) \ + ((void *)((tptr).v & ~__tagptr_mask(tptr))) + +#define tagptr_unfold_tags(tptr) \ + ((tptr).v & __tagptr_mask(tptr)) + +/* operations for the tagger pointer */ +#define tagptr_eq(_tptr1, _tptr2) ({ \ + typeof(_tptr1) tptr1 = (_tptr1); \ + typeof(_tptr2) tptr2 = (_tptr2); \ + (void)(&tptr1 == &tptr2); \ +(tptr1).v == (tptr2).v; }) + +/* lock-free CAS operation */ +#define tagptr_cmpxchg(_ptptr, _o, _n) ({ \ + typeof(_ptptr) ptptr = (_ptptr); \ + typeof(_o) o = (_o); \ + typeof(_n) n = (_n); \ + (void)(&o == &n); \ + (void)(&o == ptptr); \ +tagptr_init(o, cmpxchg(&ptptr->v, o.v, n.v)); }) + +/* wrap WRITE_ONCE if atomic update is needed */ +#define tagptr_replace_tags(_ptptr, tags) ({ \ + typeof(_ptptr) ptptr = (_ptptr); \ + *ptptr = tagptr_fold(*ptptr, tagptr_unfold_ptr(*ptptr), tags); \ +*ptptr; }) + +#define tagptr_set_tags(_ptptr, _tags) ({ \ + typeof(_ptptr) ptptr = (_ptptr); \ + const typeof(_tags) tags = (_tags); \ + if (__builtin_constant_p(tags) && (tags & ~__tagptr_mask(*ptptr))) \ + __bad_tagptr_tags(); \ + ptptr->v |= tags; \ +*ptptr; }) + +#define tagptr_clear_tags(_ptptr, _tags) ({ \ + typeof(_ptptr) ptptr = (_ptptr); \ + const typeof(_tags) tags = (_tags); \ + if (__builtin_constant_p(tags) && (tags & ~__tagptr_mask(*ptptr))) \ + __bad_tagptr_tags(); \ + ptptr->v &= ~tags; \ +*ptptr; }) + +#endif + -- 1.9.1
WARNING: multiple messages have this Message-ID (diff)
From: gaoxiang25@huawei.com (Gao Xiang) Subject: [PATCH 13/25] staging: erofs: <linux/tagptr.h>: introduce tagged pointer Date: Thu, 26 Jul 2018 20:21:56 +0800 [thread overview] Message-ID: <1532607728-103372-14-git-send-email-gaoxiang25@huawei.com> (raw) In-Reply-To: <1532607728-103372-1-git-send-email-gaoxiang25@huawei.com> Currently kernel has scattered tagged pointer usages hacked by hand in plain code, without a unique and portable functionset to highlight the tagged pointer itself and wrap these hacked code in order to clean up all over meaningless magic masks. Therefore, this patch introduces simple generic methods to fold tags into a pointer integer. It currently supports the last n bits of the pointer for tags, which can be selected by users. In addition, it will also be used for the upcoming EROFS filesystem, which heavily uses tagged pointer approach for high performance and reducing extra memory allocation. Link: https://en.wikipedia.org/wiki/Tagged_pointer Signed-off-by: Gao Xiang <gaoxiang25 at huawei.com> --- drivers/staging/erofs/include/linux/tagptr.h | 110 +++++++++++++++++++++++++++ 1 file changed, 110 insertions(+) create mode 100644 drivers/staging/erofs/include/linux/tagptr.h diff --git a/drivers/staging/erofs/include/linux/tagptr.h b/drivers/staging/erofs/include/linux/tagptr.h new file mode 100644 index 0000000..ccd106d --- /dev/null +++ b/drivers/staging/erofs/include/linux/tagptr.h @@ -0,0 +1,110 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * Tagged pointer implementation + * + * Copyright (C) 2018 Gao Xiang <gaoxiang25 at huawei.com> + */ +#ifndef _LINUX_TAGPTR_H +#define _LINUX_TAGPTR_H + +#include <linux/types.h> +#include <linux/build_bug.h> + +/* + * the name of tagged pointer types are tagptr{1, 2, 3...}_t + * avoid directly using the internal structs __tagptr{1, 2, 3...} + */ +#define __MAKE_TAGPTR(n) \ +typedef struct __tagptr##n { \ + uintptr_t v; \ +} tagptr##n##_t; + +__MAKE_TAGPTR(1) +__MAKE_TAGPTR(2) +__MAKE_TAGPTR(3) +__MAKE_TAGPTR(4) + +#undef __MAKE_TAGPTR + +extern void __compiletime_error("bad tagptr tags") + __bad_tagptr_tags(void); + +extern void __compiletime_error("bad tagptr type") + __bad_tagptr_type(void); + +/* fix the broken usage of "#define tagptr2_t tagptr3_t" by users */ +#define __tagptr_mask_1(ptr, n) \ + __builtin_types_compatible_p(typeof(ptr), struct __tagptr##n) ? \ + (1UL << (n)) - 1 : + +#define __tagptr_mask(ptr) (\ + __tagptr_mask_1(ptr, 1) ( \ + __tagptr_mask_1(ptr, 2) ( \ + __tagptr_mask_1(ptr, 3) ( \ + __tagptr_mask_1(ptr, 4) ( \ + __bad_tagptr_type(), 0))))) + +/* generate a tagged pointer from a raw value */ +#define tagptr_init(type, val) \ + ((typeof(type)){ .v = (uintptr_t)(val) }) + +/* + * directly cast a tagged pointer to the native pointer type, which + * could be used for backward compatibility of existing code. + */ +#define tagptr_cast_ptr(tptr) ((void *)(tptr).v) + +/* encode tagged pointers */ +#define tagptr_fold(type, ptr, _tags) ({ \ + const typeof(_tags) tags = (_tags); \ + if (__builtin_constant_p(tags) && (tags & ~__tagptr_mask(type))) \ + __bad_tagptr_tags(); \ +tagptr_init(type, (uintptr_t)(ptr) | tags); }) + +/* decode tagged pointers */ +#define tagptr_unfold_ptr(tptr) \ + ((void *)((tptr).v & ~__tagptr_mask(tptr))) + +#define tagptr_unfold_tags(tptr) \ + ((tptr).v & __tagptr_mask(tptr)) + +/* operations for the tagger pointer */ +#define tagptr_eq(_tptr1, _tptr2) ({ \ + typeof(_tptr1) tptr1 = (_tptr1); \ + typeof(_tptr2) tptr2 = (_tptr2); \ + (void)(&tptr1 == &tptr2); \ +(tptr1).v == (tptr2).v; }) + +/* lock-free CAS operation */ +#define tagptr_cmpxchg(_ptptr, _o, _n) ({ \ + typeof(_ptptr) ptptr = (_ptptr); \ + typeof(_o) o = (_o); \ + typeof(_n) n = (_n); \ + (void)(&o == &n); \ + (void)(&o == ptptr); \ +tagptr_init(o, cmpxchg(&ptptr->v, o.v, n.v)); }) + +/* wrap WRITE_ONCE if atomic update is needed */ +#define tagptr_replace_tags(_ptptr, tags) ({ \ + typeof(_ptptr) ptptr = (_ptptr); \ + *ptptr = tagptr_fold(*ptptr, tagptr_unfold_ptr(*ptptr), tags); \ +*ptptr; }) + +#define tagptr_set_tags(_ptptr, _tags) ({ \ + typeof(_ptptr) ptptr = (_ptptr); \ + const typeof(_tags) tags = (_tags); \ + if (__builtin_constant_p(tags) && (tags & ~__tagptr_mask(*ptptr))) \ + __bad_tagptr_tags(); \ + ptptr->v |= tags; \ +*ptptr; }) + +#define tagptr_clear_tags(_ptptr, _tags) ({ \ + typeof(_ptptr) ptptr = (_ptptr); \ + const typeof(_tags) tags = (_tags); \ + if (__builtin_constant_p(tags) && (tags & ~__tagptr_mask(*ptptr))) \ + __bad_tagptr_tags(); \ + ptptr->v &= ~tags; \ +*ptptr; }) + +#endif + -- 1.9.1
next prev parent reply other threads:[~2018-07-26 12:26 UTC|newest] Thread overview: 112+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-05-31 11:06 [NOMERGE] [RFC PATCH 00/12] erofs: introduce erofs file system Gao Xiang 2018-06-01 7:48 ` Richard Weinberger 2018-06-01 9:11 ` Gao Xiang 2018-06-01 9:28 ` Richard Weinberger 2018-06-01 11:16 ` Gao Xiang 2018-06-07 10:26 ` Pavel Machek 2018-07-27 0:55 ` Joey Pabalinas 2018-07-27 0:57 ` Joey Pabalinas 2018-07-26 12:21 ` [PATCH 00/25] staging: " Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` [PATCH 01/25] staging: erofs: add on-disk layout Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` [PATCH 02/25] staging: erofs: add erofs in-memory stuffs Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` [PATCH 03/25] staging: erofs: add super block operations Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` [PATCH 04/25] staging: erofs: add raw address_space operations Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` [PATCH 05/25] staging: erofs: add inode operations Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` [PATCH 06/25] staging: erofs: add directory operations Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` [PATCH 07/25] staging: erofs: add namei functions Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` [PATCH 08/25] staging: erofs: update Kconfig and Makefile Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` [PATCH 09/25] staging: erofs: introduce xattr & acl support Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` [PATCH 10/25] staging: erofs: support special inode Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` [PATCH 11/25] staging: erofs: introduce error injection infrastructure Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` [PATCH 12/25] staging: erofs: support tracepoint Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` Gao Xiang [this message] 2018-07-26 12:21 ` [PATCH 13/25] staging: erofs: <linux/tagptr.h>: introduce tagged pointer Gao Xiang 2018-07-26 12:21 ` [PATCH 14/25] staging: erofs: introduce pagevec for unzip subsystem Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` [PATCH 15/25] staging: erofs: add erofs_map_blocks_iter Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:21 ` [PATCH 16/25] staging: erofs: add erofs_allocpage Gao Xiang 2018-07-26 12:21 ` Gao Xiang 2018-07-26 12:22 ` [PATCH 17/25] staging: erofs: globalize prepare_bio and __submit_bio Gao Xiang 2018-07-26 12:22 ` Gao Xiang 2018-07-26 12:22 ` [PATCH 18/25] staging: erofs: introduce a customized LZ4 decompression Gao Xiang 2018-07-26 12:22 ` Gao Xiang 2018-07-26 12:22 ` [PATCH 19/25] staging: erofs: add a generic z_erofs VLE decompressor Gao Xiang 2018-07-26 12:22 ` Gao Xiang 2018-07-26 12:22 ` [PATCH 20/25] staging: erofs: introduce superblock registration Gao Xiang 2018-07-26 12:22 ` Gao Xiang 2018-07-26 12:22 ` [PATCH 21/25] staging: erofs: introduce erofs shrinker Gao Xiang 2018-07-26 12:22 ` Gao Xiang 2018-07-26 12:22 ` [PATCH 22/25] staging: erofs: introduce workstation for decompression Gao Xiang 2018-07-26 12:22 ` Gao Xiang 2018-07-26 12:22 ` [PATCH 23/25] staging: erofs: introduce VLE decompression support Gao Xiang 2018-07-26 12:22 ` Gao Xiang 2018-07-26 12:22 ` [PATCH 24/25] staging: erofs: introduce cached decompression Gao Xiang 2018-07-26 12:22 ` Gao Xiang 2018-07-26 12:22 ` [PATCH 25/25] staging: erofs: add a TODO and update MAINTAINERS for staging Gao Xiang 2018-07-26 12:22 ` Gao Xiang 2018-07-28 7:10 ` [PATCH] staging: erofs: fix a compile warning of Z_EROFS_VLE_VMAP_ONSTACK_PAGES Gao Xiang 2018-07-28 7:10 ` Gao Xiang 2018-07-28 10:43 ` Chao Yu 2018-07-28 10:43 ` Chao Yu 2018-07-29 5:34 ` [PATCH 1/2] staging: erofs: fix compile error without built-in decompression support Gao Xiang 2018-07-29 5:34 ` Gao Xiang 2018-07-29 5:37 ` [PATCH 2/2] staging: erofs: fix conditional uninitialized `pcn' in z_erofs_map_blocks_iter Gao Xiang 2018-07-29 5:37 ` Gao Xiang 2018-07-30 1:51 ` [PATCH] staging: erofs: use the wrapped PTR_ERR_OR_ZERO instead of open code Gao Xiang 2018-07-30 1:51 ` Gao Xiang 2018-07-30 6:58 ` Chao Yu 2018-07-30 6:58 ` Chao Yu 2018-08-01 6:38 ` [PATCH 1/2] staging: erofs: add the missing break in z_erofs_map_blocks_iter Gao Xiang 2018-08-01 6:38 ` Gao Xiang 2018-08-01 6:38 ` [PATCH 2/2] staging: erofs: remove a redundant marco in xattr Gao Xiang 2018-08-01 6:38 ` Gao Xiang 2018-08-01 9:02 ` [PATCH 1/2] staging: erofs: add the missing break in z_erofs_map_blocks_iter Dan Carpenter 2018-08-01 9:02 ` Dan Carpenter 2018-08-01 9:19 ` Gao Xiang 2018-08-01 9:19 ` Gao Xiang 2018-08-01 9:36 ` [PATCH RESEND " Gao Xiang 2018-08-01 9:36 ` Gao Xiang 2018-08-01 11:36 ` Dan Carpenter 2018-08-01 11:36 ` Dan Carpenter 2018-08-01 12:08 ` Gao Xiang 2018-08-01 12:08 ` Gao Xiang 2018-07-30 2:07 ` [PATCH 2/2] staging: erofs: fix conditional uninitialized `pcn' " Chao Yu 2018-07-30 2:07 ` Chao Yu 2018-07-30 2:07 ` [PATCH 1/2] staging: erofs: fix compile error without built-in decompression support Chao Yu 2018-07-30 2:07 ` Chao Yu 2018-07-30 2:32 ` Gao Xiang 2018-07-30 2:32 ` Gao Xiang 2018-07-30 3:07 ` Chao Yu 2018-07-30 3:07 ` Chao Yu 2018-07-30 3:55 ` Gao Xiang 2018-07-30 3:55 ` Gao Xiang 2018-07-30 3:34 ` [FOR INTERNAL REVIEW] [PATCH RESEND 1/3] staging: erofs: fix incorrect code in erofs_shrink_scan Gao Xiang 2018-07-30 3:34 ` [FOR INTERNAL REVIEW] [PATCH RESEND 2/3] staging: erofs: add 'erofs_' prefixes for try_to_free_(all_)cached_page(s) Gao Xiang 2018-07-30 6:57 ` Chao Yu 2018-07-30 3:34 ` [FOR INTERNAL REVIEW] [PATCH RESEND 3/3] staging: erofs: fix conditional uninitialized `pcn' in z_erofs_map_blocks_iter Gao Xiang 2018-07-30 6:56 ` [FOR INTERNAL REVIEW] [PATCH RESEND 1/3] staging: erofs: fix incorrect code in erofs_shrink_scan Chao Yu 2018-07-27 0:25 ` [PATCH 00/25] staging: erofs: introduce erofs file system Christian Kujau 2018-07-27 1:39 ` Gao Xiang 2018-07-27 1:39 ` Gao Xiang 2018-07-27 1:56 ` Gao Xiang 2018-07-27 1:56 ` Gao Xiang 2018-07-28 7:25 ` Greg Kroah-Hartman 2018-07-28 7:25 ` Greg Kroah-Hartman 2018-07-28 9:33 ` Gao Xiang 2018-07-28 9:33 ` Gao Xiang 2018-07-28 10:34 ` Chao Yu 2018-07-28 10:34 ` Chao Yu
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=1532607728-103372-14-git-send-email-gaoxiang25@huawei.com \ --to=gaoxiang25@huawei.com \ --cc=chao@kernel.org \ --cc=devel@driverdev.osuosl.org \ --cc=gregkh@linuxfoundation.org \ --cc=hsiangkao@aol.com \ --cc=linux-erofs@lists.ozlabs.org \ --cc=linux-fsdevel@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=miaoxie@huawei.com \ --cc=weidu.du@huawei.com \ --cc=yuchao0@huawei.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.