开始注解(OOM)内存不足时的处理.

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kernel/base/include/los_oom.h

-/*
- * Copyright (c) 2013-2019, Huawei Technologies Co., Ltd. All rights reserved.
- * Copyright (c) 2020, Huawei Device Co., Ltd. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without modification,
- * are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this list of
- *    conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice, this list
- *    of conditions and the following disclaimer in the documentation and/or other materials
- *    provided with the distribution.
- *
- * 3. Neither the name of the copyright holder nor the names of its contributors may be used
- *    to endorse or promote products derived from this software without specific prior written
- *    permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
- * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
- * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
- * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
- * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#ifndef _LOS_OOM_H
-#define _LOS_OOM_H
-#include "los_typedef.h"
-
-#define OOM_TASK_PRIORITY                   9
-#define OOM_TASK_STACK_SIZE                 0x1000
-
-#define OOM_CHECK_MIN                       10      /* 0.1s */
-#define OOM_DEFAULT_CHECK_INTERVAL          100     /* 1s */
-#define OOM_CHECK_MAX                       1000    /* 10s */
-
-#define OOM_DEFAULT_LOW_MEM_THRESHOLD       0x80000  /* 512KByte */
-#define OOM_DEFAULT_LOW_MEM_THRESHOLD_MIN   0        /* 0, means always no memory */
-#define OOM_DEFAULT_LOW_MEM_THRESHOLD_MAX   0x100000 /* 1MByte */
-
-#define OOM_DEFAULT_RECLAIM_MEM_THRESHOLD   0x500000 /* 5MByte */
-
-typedef UINT32 (*OomFn)(UINTPTR param);
-
-typedef struct { //内存溢出控制块(描述符)
-    UINT32       lowMemThreshold;       /* byte */ 	//最低运行内存
-    UINT32       reclaimMemThreshold;   /* byte */	//回收内存起点
-    UINT32       checkInterval;         /* microsecond */
-    OomFn        processVictimCB;       /* process victim process cb function */ 
-    OomFn        scoreCB;               /* out of memory, the process score function */
-    UINT16       swtmrID;
-    BOOL         enabled;               /* oom is enabled or not */
-} OomCB;
-
-LITE_OS_SEC_TEXT_MINOR UINT32 OomTaskInit(VOID);
-LITE_OS_SEC_TEXT_MINOR VOID OomInfodump(VOID);
-LITE_OS_SEC_TEXT_MINOR VOID OomEnable(VOID);
-LITE_OS_SEC_TEXT_MINOR VOID OomDisable(VOID);
-LITE_OS_SEC_TEXT_MINOR VOID OomSetLowMemThreashold(UINT32 lowMemThreshold);
-LITE_OS_SEC_TEXT_MINOR VOID OomSetReclaimMemThreashold(UINT32 reclaimMemThreshold);
-LITE_OS_SEC_TEXT_MINOR VOID OomSetCheckInterval(UINT32 checkInterval);
-LITE_OS_SEC_TEXT_MINOR BOOL OomCheckProcess(VOID);
-#endif
-
+/*
+ * Copyright (c) 2013-2019, Huawei Technologies Co., Ltd. All rights reserved.
+ * Copyright (c) 2020, Huawei Device Co., Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this list of
+ *    conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *    of conditions and the following disclaimer in the documentation and/or other materials
+ *    provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its contributors may be used
+ *    to endorse or promote products derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _LOS_OOM_H
+#define _LOS_OOM_H
+#include "los_typedef.h"
+
+#define OOM_TASK_PRIORITY                   9
+#define OOM_TASK_STACK_SIZE                 0x1000
+
+#define OOM_CHECK_MIN                       10      /* 0.1s */
+#define OOM_DEFAULT_CHECK_INTERVAL          100     /* 1s */
+#define OOM_CHECK_MAX                       1000    /* 10s */
+
+#define OOM_DEFAULT_LOW_MEM_THRESHOLD       0x80000  /* 512KByte */
+#define OOM_DEFAULT_LOW_MEM_THRESHOLD_MIN   0        /* 0, means always no memory */
+#define OOM_DEFAULT_LOW_MEM_THRESHOLD_MAX   0x100000 /* 1MByte */
+
+#define OOM_DEFAULT_RECLAIM_MEM_THRESHOLD   0x500000 /* 5MByte */
+
+typedef UINT32 (*OomFn)(UINTPTR param);//内存溢出的回调函数定义
+
+typedef struct { //内存溢出控制块(描述符)
+    UINT32       lowMemThreshold;       /* byte */ 	//最低运行内存
+    UINT32       reclaimMemThreshold;   /* byte */	//回收内存起点
+    UINT32       checkInterval;         /* microsecond */
+    OomFn        processVictimCB;       /* process victim process cb function */ 
+    OomFn        scoreCB;               /* out of memory, the process score function */ //内存不足时,进程得分函数
+    UINT16       swtmrID;				//定时器ID
+    BOOL         enabled;               /* oom is enabled or not *///是否启用了内存溢出监控
+} OomCB;
+
+LITE_OS_SEC_TEXT_MINOR UINT32 OomTaskInit(VOID);
+LITE_OS_SEC_TEXT_MINOR VOID OomInfodump(VOID);
+LITE_OS_SEC_TEXT_MINOR VOID OomEnable(VOID);
+LITE_OS_SEC_TEXT_MINOR VOID OomDisable(VOID);
+LITE_OS_SEC_TEXT_MINOR VOID OomSetLowMemThreashold(UINT32 lowMemThreshold);
+LITE_OS_SEC_TEXT_MINOR VOID OomSetReclaimMemThreashold(UINT32 reclaimMemThreshold);
+LITE_OS_SEC_TEXT_MINOR VOID OomSetCheckInterval(UINT32 checkInterval);
+LITE_OS_SEC_TEXT_MINOR BOOL OomCheckProcess(VOID);
+#endif
+

kernel/base/include/los_vm_phys.h

@@ -55,7 +55,7 @@ LRU是Least Recently Used的缩写，即最近最少使用页面置换算法，
 #define min(x, y) ((x) < (y) ? (x) : (y))
 #endif
 
-#define VM_PAGE_TO_PHYS(page)    (page->physAddr)//获取页面物理地址
+#define VM_PAGE_TO_PHYS(page)    (page->physAddr)//获取物理页框的物理基地址
 #define VM_ORDER_TO_PAGES(order) (1 << (order))//伙伴算法由order 定位到该块组的页面单位,例如:order=2时，page[4]
 #define VM_ORDER_TO_PHYS(order)  (1 << (PAGE_SHIFT + (order)))//通过order块组跳到物理地址
 #define VM_PHYS_TO_ORDER(phys)   (min(LOS_LowBitGet((phys) >> PAGE_SHIFT), VM_LIST_ORDER_MAX - 1))//通过物理地址定位到order

kernel/base/vm/los_vm_phys.c

@@ -491,7 +491,10 @@ LosVmPage *LOS_PhysPageAlloc(VOID)
 {
     return OsVmPhysPagesGet(ONE_PAGE);//分配一页物理页
 }
-
+/******************************************************************************
+ 分配nPages页个物理页框,并将页框挂入list
+ 返回已分配的页面大小,不负责一定能分配到nPages的页框
+******************************************************************************/
 size_t LOS_PhysPagesAlloc(size_t nPages, LOS_DL_LIST *list)
 {
     LosVmPage *page = NULL;
@@ -506,7 +509,7 @@ size_t LOS_PhysPagesAlloc(size_t nPages, LOS_DL_LIST *list)
         if (page == NULL) {
             break;
         }
-        LOS_ListTailInsert(list, &page->node);//从参数链表list尾部插入新页面结点
+        LOS_ListTailInsert(list, &page->node);//从参数链表list尾部挂入新页面结点
         count++;
     }
 

kernel/base/vm/oom.c

-/*
- * Copyright (c) 2013-2019, Huawei Technologies Co., Ltd. All rights reserved.
- * Copyright (c) 2020, Huawei Device Co., Ltd. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without modification,
- * are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this list of
- *    conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice, this list
- *    of conditions and the following disclaimer in the documentation and/or other materials
- *    provided with the distribution.
- *
- * 3. Neither the name of the copyright holder nor the names of its contributors may be used
- *    to endorse or promote products derived from this software without specific prior written
- *    permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
- * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
- * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
- * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
- * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include "sys_config.h"
-#include "los_oom.h"
-#include "los_vm_dump.h"
-#include "los_vm_lock.h"
-#include "los_vm_phys.h"
-#include "los_vm_filemap.h"
-#include "los_process_pri.h"
-#if (LOSCFG_BASE_CORE_SWTMR == YES)
-#include "los_swtmr_pri.h"
-#endif
-
-#ifdef LOSCFG_FS_VFS
-#include "console.h"
-#endif
-
-#ifdef __cplusplus
-#if __cplusplus
-extern "C" {
-#endif /* __cplusplus */
-#endif /* __cplusplus */
-
-LITE_OS_SEC_BSS OomCB *g_oomCB = NULL;
-static SPIN_LOCK_INIT(g_oomSpinLock);//内存溢出自旋锁
-
-LITE_OS_SEC_TEXT_MINOR STATIC UINT32 OomScoreProcess(LosProcessCB *candidateProcess)
-{
-    UINT32 actualPm;
-
-#if (LOSCFG_KERNEL_SMP != YES)
-    (VOID)LOS_MuxAcquire(&candidateProcess->vmSpace->regionMux);
-#endif
-    /* we only consider actual physical memory here. */ //只考虑实际的物理内存
-    OsUProcessPmUsage(candidateProcess->vmSpace, NULL, &actualPm);
-#if (LOSCFG_KERNEL_SMP != YES)
-    (VOID)LOS_MuxRelease(&candidateProcess->vmSpace->regionMux);
-#endif
-    return actualPm;
-}
-
-LITE_OS_SEC_TEXT_MINOR STATIC UINT32 OomKillProcess(UINTPTR param)
-{
-    /* we will not kill process, and do nothing here */
-    return LOS_OK;
-}
-
-LITE_OS_SEC_TEXT_MINOR STATIC UINT32 OomForceShrinkMemory(VOID)
-{
-    UINT32 i;
-    UINT32 reclaimMemPages = 0;
-
-    /*
-     * TryShrinkMemory maybe reclaim 0 pages in the first time from active list
-     * to inactive list, and in the second time reclaim memory from inactive list.
-     */
-    for (i = 0; i < MAX_SHRINK_PAGECACHE_TRY; i++) {
-        reclaimMemPages += OsTryShrinkMemory(0);
-    }
-
-    return reclaimMemPages;
-}
-
-LITE_OS_SEC_TEXT_MINOR STATIC BOOL OomReclaimPageCache(VOID)
-{
-    UINT32 totalPm = 0;
-    UINT32 usedPm = 0;
-    BOOL isReclaimMemory = FALSE;
-    UINT32 reclaimMemPages;
-    UINT32 i;
-
-    for (i = 0; i < MAX_SHRINK_PAGECACHE_TRY; i++) {
-        OsVmPhysUsedInfoGet(&usedPm, &totalPm);
-        isReclaimMemory = ((totalPm - usedPm) << PAGE_SHIFT) < g_oomCB->reclaimMemThreshold;
-        if (isReclaimMemory) {
-            /*
-             * we do force memory reclaim from page cache here.
-             * if we get memory, we will reclaim pagecache memory again.
-             * if there is no memory to reclaim, we will return.
-             */
-            reclaimMemPages = OomForceShrinkMemory();
-            if (reclaimMemPages > 0) {
-                continue;
-            }
-        }
-        break;
-    }
-
-    return isReclaimMemory;
-}
-
-/*
- * check is low memory or not, if low memory, try to kill process. //检查内存是否不足，如果内存不足，请尝试终止进程。
- * return is kill process or not. //返回是否kill进程
- */
-LITE_OS_SEC_TEXT_MINOR BOOL OomCheckProcess(VOID)
-{
-    UINT32 totalPm;
-    UINT32 usedPm;
-    BOOL isLowMemory = FALSE;
-
-    /*
-     * spinlock the current core schedule, make sure oom process atomic //旋转锁定当前核心计划，确保oom进程原子化
-     * spinlock other place entering OomCheckProcess, make sure oom process mutex //旋转锁定其他进入OomCheckProcess的地方，确保oom进程互斥
-     */
-    LOS_SpinLock(&g_oomSpinLock);
-
-    /* first we will check if we need to reclaim pagecache memory */
-    if (OomReclaimPageCache() == FALSE) {
-        goto NO_VICTIM_PROCESS;
-    }
-
-    /* get free bytes */
-    OsVmPhysUsedInfoGet(&usedPm, &totalPm);
-    isLowMemory = ((totalPm - usedPm) << PAGE_SHIFT) < g_oomCB->lowMemThreshold;
-    if (isLowMemory) {
-        PRINTK("[oom] OS is in low memory state\n"
-               "total physical memory: %#x(byte), used: %#x(byte),"
-               "free: %#x(byte), low memory threshold: %#x(byte)\n",
-               totalPm << PAGE_SHIFT, usedPm << PAGE_SHIFT,
-               (totalPm - usedPm) << PAGE_SHIFT, g_oomCB->lowMemThreshold);
-    }
-
-NO_VICTIM_PROCESS:
-    LOS_SpinUnlock(&g_oomSpinLock);
-    return isLowMemory;
-}
-
-#ifdef LOSCFG_ENABLE_OOM_LOOP_TASK	//内存溢出监测任务开关
-STATIC VOID OomWriteEvent(VOID) // OomTaskInit中创建的定时器回调
-{
-    OsWriteResourceEvent(OS_RESOURCE_EVENT_OOM);//写内存溢出事件
-}
-#endif
-
-LITE_OS_SEC_TEXT_MINOR VOID OomInfodump(VOID) //打印内存溢出信息
-{
-    PRINTK("[oom] oom loop task status: %s\n"
-           "      oom low memory threshold: %#x(byte)\n"
-           "      oom reclaim memory threshold: %#x(byte)\n"
-           "      oom check interval: %d(microsecond)\n",
-           g_oomCB->enabled ? "enabled" : "disabled",
-           g_oomCB->lowMemThreshold, g_oomCB->reclaimMemThreshold,
-           g_oomCB->checkInterval);
-}
-
-LITE_OS_SEC_TEXT_MINOR VOID OomSetLowMemThreashold(UINT32 lowMemThreshold)
-{
-    if ((lowMemThreshold > OOM_DEFAULT_LOW_MEM_THRESHOLD_MAX)) {
-        PRINTK("[oom] low memory threshold %#x(byte) invalid,"
-               "should be in [%#x, %#x](byte)\n",
-               lowMemThreshold, OOM_DEFAULT_LOW_MEM_THRESHOLD_MIN,
-               OOM_DEFAULT_LOW_MEM_THRESHOLD_MAX);
-    } else {
-        g_oomCB->lowMemThreshold = lowMemThreshold;
-        PRINTK("[oom] set oom low memory threshold %#x(byte) successful\n",
-               g_oomCB->lowMemThreshold);
-    }
-}
-
-LITE_OS_SEC_TEXT_MINOR VOID OomSetReclaimMemThreashold(UINT32 reclaimMemThreshold)
-{
-    UINT32 totalPm = 0;
-    UINT32 usedPm = 0;
-
-    OsVmPhysUsedInfoGet(&usedPm, &totalPm);
-    if ((reclaimMemThreshold >= (totalPm << PAGE_SHIFT)) ||
-        (reclaimMemThreshold < g_oomCB->lowMemThreshold)) {
-        PRINTK("[oom] reclaim memory threshold %#x(byte) invalid,"
-               "should be in [%#x, %#x)(byte)\n",
-               reclaimMemThreshold, g_oomCB->lowMemThreshold, (totalPm << PAGE_SHIFT));
-    } else {
-        g_oomCB->reclaimMemThreshold = reclaimMemThreshold;
-        PRINTK("[oom] set oom reclaim memory threshold %#x(byte) successful\n",
-               g_oomCB->reclaimMemThreshold);
-    }
-}
-
-LITE_OS_SEC_TEXT_MINOR VOID OomSetCheckInterval(UINT32 checkInterval)
-{
-    if ((checkInterval >= OOM_CHECK_MIN) && (checkInterval <= OOM_CHECK_MAX)) {
-        g_oomCB->checkInterval = checkInterval;
-        PRINTK("[oom] set oom check interval (%d)ms successful\n",
-               g_oomCB->checkInterval);
-    } else {
-        PRINTK("[oom] set oom check interval (%d)ms failed, should be in [%d, %d]\n",
-               g_oomCB->checkInterval, OOM_CHECK_MIN, OOM_CHECK_MAX);
-    }
-}
-//内存溢出任务初始化
-LITE_OS_SEC_TEXT_MINOR UINT32 OomTaskInit(VOID)
-{
-    g_oomCB = (OomCB *)LOS_MemAlloc(m_aucSysMem0, sizeof(OomCB));
-    if (g_oomCB == NULL) {
-        VM_ERR("oom task init failed, malloc OomCB failed.");
-        return LOS_NOK;
-    }
-
-    g_oomCB->lowMemThreshold     = OOM_DEFAULT_LOW_MEM_THRESHOLD;
-    g_oomCB->reclaimMemThreshold = OOM_DEFAULT_RECLAIM_MEM_THRESHOLD;
-    g_oomCB->checkInterval       = OOM_DEFAULT_CHECK_INTERVAL;
-    g_oomCB->processVictimCB     = (OomFn)OomKillProcess;
-    g_oomCB->scoreCB             = (OomFn)OomScoreProcess;
-    g_oomCB->enabled             = FALSE;
-
-#ifdef LOSCFG_ENABLE_OOM_LOOP_TASK //内存溢出检测开关
-    g_oomCB->enabled         = TRUE;
-    UINT32 ret = LOS_SwtmrCreate(g_oomCB->checkInterval, LOS_SWTMR_MODE_PERIOD, (SWTMR_PROC_FUNC)OomWriteEvent,
-                                 &g_oomCB->swtmrID, (UINTPTR)g_oomCB);//创建检测定时器
-    if (ret != LOS_OK) {
-        return ret;
-    }
-
-    return LOS_SwtmrStart(g_oomCB->swtmrID);
-#else
-    return LOS_OK;
-#endif
-}
-
-#ifdef __cplusplus
-#if __cplusplus
-}
-#endif
-#endif
+/*
+ * Copyright (c) 2013-2019, Huawei Technologies Co., Ltd. All rights reserved.
+ * Copyright (c) 2020, Huawei Device Co., Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this list of
+ *    conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *    of conditions and the following disclaimer in the documentation and/or other materials
+ *    provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its contributors may be used
+ *    to endorse or promote products derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "sys_config.h"
+#include "los_oom.h"
+#include "los_vm_dump.h"
+#include "los_vm_lock.h"
+#include "los_vm_phys.h"
+#include "los_vm_filemap.h"
+#include "los_process_pri.h"
+#if (LOSCFG_BASE_CORE_SWTMR == YES)
+#include "los_swtmr_pri.h"
+#endif
+
+#ifdef LOSCFG_FS_VFS
+#include "console.h"
+#endif
+
+#ifdef __cplusplus
+#if __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+#endif /* __cplusplus */
+
+LITE_OS_SEC_BSS OomCB *g_oomCB = NULL; //全局内存溢出控制块
+static SPIN_LOCK_INIT(g_oomSpinLock);//内存溢出自旋锁
+
+LITE_OS_SEC_TEXT_MINOR STATIC UINT32 OomScoreProcess(LosProcessCB *candidateProcess)
+{
+    UINT32 actualPm;
+
+#if (LOSCFG_KERNEL_SMP != YES)
+    (VOID)LOS_MuxAcquire(&candidateProcess->vmSpace->regionMux);
+#endif
+    /* we only consider actual physical memory here. */ //只考虑实际的物理内存
+    OsUProcessPmUsage(candidateProcess->vmSpace, NULL, &actualPm);
+#if (LOSCFG_KERNEL_SMP != YES)
+    (VOID)LOS_MuxRelease(&candidateProcess->vmSpace->regionMux);
+#endif
+    return actualPm;
+}
+//内存不足时,进程
+LITE_OS_SEC_TEXT_MINOR STATIC UINT32 OomKillProcess(UINTPTR param)
+{
+    /* we will not kill process, and do nothing here */
+    return LOS_OK;
+}
+
+LITE_OS_SEC_TEXT_MINOR STATIC UINT32 OomForceShrinkMemory(VOID)
+{
+    UINT32 i;
+    UINT32 reclaimMemPages = 0;
+
+    /*
+     * TryShrinkMemory maybe reclaim 0 pages in the first time from active list
+     * to inactive list, and in the second time reclaim memory from inactive list.
+     */
+    for (i = 0; i < MAX_SHRINK_PAGECACHE_TRY; i++) {
+        reclaimMemPages += OsTryShrinkMemory(0);
+    }
+
+    return reclaimMemPages;
+}
+
+LITE_OS_SEC_TEXT_MINOR STATIC BOOL OomReclaimPageCache(VOID)
+{
+    UINT32 totalPm = 0;
+    UINT32 usedPm = 0;
+    BOOL isReclaimMemory = FALSE;
+    UINT32 reclaimMemPages;
+    UINT32 i;
+
+    for (i = 0; i < MAX_SHRINK_PAGECACHE_TRY; i++) {
+        OsVmPhysUsedInfoGet(&usedPm, &totalPm);
+        isReclaimMemory = ((totalPm - usedPm) << PAGE_SHIFT) < g_oomCB->reclaimMemThreshold;
+        if (isReclaimMemory) {
+            /*
+             * we do force memory reclaim from page cache here.
+             * if we get memory, we will reclaim pagecache memory again.
+             * if there is no memory to reclaim, we will return.
+             */
+            reclaimMemPages = OomForceShrinkMemory();
+            if (reclaimMemPages > 0) {
+                continue;
+            }
+        }
+        break;
+    }
+
+    return isReclaimMemory;
+}
+
+/*
+ * check is low memory or not, if low memory, try to kill process. //检查内存是否不足，如果内存不足，请尝试终止进程。
+ * return is kill process or not. //返回是否kill进程
+ */
+LITE_OS_SEC_TEXT_MINOR BOOL OomCheckProcess(VOID)
+{
+    UINT32 totalPm;
+    UINT32 usedPm;
+    BOOL isLowMemory = FALSE;
+
+    /*
+     * spinlock the current core schedule, make sure oom process atomic //旋转锁定当前核心计划，确保oom进程原子化
+     * spinlock other place entering OomCheckProcess, make sure oom process mutex //旋转锁定其他进入OomCheckProcess的地方，确保oom进程互斥
+     */
+    LOS_SpinLock(&g_oomSpinLock);
+
+    /* first we will check if we need to reclaim pagecache memory */
+    if (OomReclaimPageCache() == FALSE) {
+        goto NO_VICTIM_PROCESS;
+    }
+
+    /* get free bytes */
+    OsVmPhysUsedInfoGet(&usedPm, &totalPm);
+    isLowMemory = ((totalPm - usedPm) << PAGE_SHIFT) < g_oomCB->lowMemThreshold;
+    if (isLowMemory) {
+        PRINTK("[oom] OS is in low memory state\n"
+               "total physical memory: %#x(byte), used: %#x(byte),"
+               "free: %#x(byte), low memory threshold: %#x(byte)\n",
+               totalPm << PAGE_SHIFT, usedPm << PAGE_SHIFT,
+               (totalPm - usedPm) << PAGE_SHIFT, g_oomCB->lowMemThreshold);
+    }
+
+NO_VICTIM_PROCESS:
+    LOS_SpinUnlock(&g_oomSpinLock);
+    return isLowMemory;
+}
+
+#ifdef LOSCFG_ENABLE_OOM_LOOP_TASK	//内存溢出监测任务开关
+STATIC VOID OomWriteEvent(VOID) // OomTaskInit中创建的定时器回调
+{
+    OsWriteResourceEvent(OS_RESOURCE_EVENT_OOM);//写内存溢出事件
+}
+#endif
+
+LITE_OS_SEC_TEXT_MINOR VOID OomInfodump(VOID) //打印内存溢出信息
+{
+    PRINTK("[oom] oom loop task status: %s\n"
+           "      oom low memory threshold: %#x(byte)\n"
+           "      oom reclaim memory threshold: %#x(byte)\n"
+           "      oom check interval: %d(microsecond)\n",
+           g_oomCB->enabled ? "enabled" : "disabled",
+           g_oomCB->lowMemThreshold, g_oomCB->reclaimMemThreshold,
+           g_oomCB->checkInterval);
+}
+
+LITE_OS_SEC_TEXT_MINOR VOID OomSetLowMemThreashold(UINT32 lowMemThreshold)
+{
+    if ((lowMemThreshold > OOM_DEFAULT_LOW_MEM_THRESHOLD_MAX)) {
+        PRINTK("[oom] low memory threshold %#x(byte) invalid,"
+               "should be in [%#x, %#x](byte)\n",
+               lowMemThreshold, OOM_DEFAULT_LOW_MEM_THRESHOLD_MIN,
+               OOM_DEFAULT_LOW_MEM_THRESHOLD_MAX);
+    } else {
+        g_oomCB->lowMemThreshold = lowMemThreshold;
+        PRINTK("[oom] set oom low memory threshold %#x(byte) successful\n",
+               g_oomCB->lowMemThreshold);
+    }
+}
+
+LITE_OS_SEC_TEXT_MINOR VOID OomSetReclaimMemThreashold(UINT32 reclaimMemThreshold)
+{
+    UINT32 totalPm = 0;
+    UINT32 usedPm = 0;
+
+    OsVmPhysUsedInfoGet(&usedPm, &totalPm);
+    if ((reclaimMemThreshold >= (totalPm << PAGE_SHIFT)) ||
+        (reclaimMemThreshold < g_oomCB->lowMemThreshold)) {
+        PRINTK("[oom] reclaim memory threshold %#x(byte) invalid,"
+               "should be in [%#x, %#x)(byte)\n",
+               reclaimMemThreshold, g_oomCB->lowMemThreshold, (totalPm << PAGE_SHIFT));
+    } else {
+        g_oomCB->reclaimMemThreshold = reclaimMemThreshold;
+        PRINTK("[oom] set oom reclaim memory threshold %#x(byte) successful\n",
+               g_oomCB->reclaimMemThreshold);
+    }
+}
+
+LITE_OS_SEC_TEXT_MINOR VOID OomSetCheckInterval(UINT32 checkInterval)
+{
+    if ((checkInterval >= OOM_CHECK_MIN) && (checkInterval <= OOM_CHECK_MAX)) {
+        g_oomCB->checkInterval = checkInterval;
+        PRINTK("[oom] set oom check interval (%d)ms successful\n",
+               g_oomCB->checkInterval);
+    } else {
+        PRINTK("[oom] set oom check interval (%d)ms failed, should be in [%d, %d]\n",
+               g_oomCB->checkInterval, OOM_CHECK_MIN, OOM_CHECK_MAX);
+    }
+}
+//内存溢出任务初始化
+LITE_OS_SEC_TEXT_MINOR UINT32 OomTaskInit(VOID)
+{
+    g_oomCB = (OomCB *)LOS_MemAlloc(m_aucSysMem0, sizeof(OomCB));
+    if (g_oomCB == NULL) {
+        VM_ERR("oom task init failed, malloc OomCB failed.");
+        return LOS_NOK;
+    }
+
+    g_oomCB->lowMemThreshold     = OOM_DEFAULT_LOW_MEM_THRESHOLD;
+    g_oomCB->reclaimMemThreshold = OOM_DEFAULT_RECLAIM_MEM_THRESHOLD;
+    g_oomCB->checkInterval       = OOM_DEFAULT_CHECK_INTERVAL;
+    g_oomCB->processVictimCB     = (OomFn)OomKillProcess;
+    g_oomCB->scoreCB             = (OomFn)OomScoreProcess;
+    g_oomCB->enabled             = FALSE;
+
+#ifdef LOSCFG_ENABLE_OOM_LOOP_TASK //内存溢出检测开关
+    g_oomCB->enabled         = TRUE;
+    UINT32 ret = LOS_SwtmrCreate(g_oomCB->checkInterval, LOS_SWTMR_MODE_PERIOD, (SWTMR_PROC_FUNC)OomWriteEvent,
+                                 &g_oomCB->swtmrID, (UINTPTR)g_oomCB);//创建检测定时器
+    if (ret != LOS_OK) {
+        return ret;
+    }
+
+    return LOS_SwtmrStart(g_oomCB->swtmrID);
+#else
+    return LOS_OK;
+#endif
+}
+
+#ifdef __cplusplus
+#if __cplusplus
+}
+#endif
+#endif

kernel/base/vm/shm.c

@@ -212,7 +212,12 @@ STATIC VOID ShmPagesRefDec(struct shmIDSource *seg)
         LOS_AtomicDec(&page->refCounts);
     }
 }
-//分配共享页
+
+/******************************************************************************
+ 为共享段分配物理内存
+ 例如:参数size = 4097, LOS_Align(size, PAGE_SIZE) = 8192
+ 分配页数    size >> PAGE_SHIFT = 2页 
+******************************************************************************/
 STATIC INT32 ShmAllocSeg(key_t key, size_t size, int shmflg)
 {
     INT32 i;
@@ -224,9 +229,9 @@ STATIC INT32 ShmAllocSeg(key_t key, size_t size, int shmflg)
         (size > g_shmInfo.shmmax)) {
         return -EINVAL;
     }
-    size = LOS_Align(size, PAGE_SIZE);
+    size = LOS_Align(size, PAGE_SIZE);//必须对齐 
 
-    for (i = 0; i < g_shmInfo.shmmni; i++) {
+    for (i = 0; i < g_shmInfo.shmmni; i++) {//试图找到一个空闲段与参数key绑定
         if (g_shmSegs[i].status & SHM_SEG_FREE) {//找到空闲段
             g_shmSegs[i].status &= ~SHM_SEG_FREE;//变成非空闲状态
             segNum = i;//标号
@@ -240,17 +245,17 @@ STATIC INT32 ShmAllocSeg(key_t key, size_t size, int shmflg)
 
     seg = &g_shmSegs[segNum];
     count = LOS_PhysPagesAlloc(size >> PAGE_SHIFT, &seg->node);//分配共享页面,函数内部把node都挂好了.
-    if (count != (size >> PAGE_SHIFT)) {//异常释放
-        (VOID)LOS_PhysPagesFree(&seg->node);//
-        seg->status = SHM_SEG_FREE;//回归seg池
+    if (count != (size >> PAGE_SHIFT)) {//当未分配到足够的内存时,处理方式是:不稀罕给那么点,舍弃!
+        (VOID)LOS_PhysPagesFree(&seg->node);//释放节点上的物理页框
+        seg->status = SHM_SEG_FREE;//共享段变回空闲状态
         return -ENOMEM;
     }
-    ShmSetSharedFlag(seg);//node的每个页面设置为此乃共享页也
+    ShmSetSharedFlag(seg);//将node的每个页面设置为共享页
 
-    seg->status |= SHM_SEG_USED;	//段已使用
+    seg->status |= SHM_SEG_USED;	//共享段贴上已在使用的标签
     seg->ds.shm_perm.mode = (unsigned int)shmflg & ACCESSPERMS; //使用权限
-    seg->ds.shm_perm.key = key;//
-    seg->ds.shm_segsz = size;
+    seg->ds.shm_perm.key = key;//保存参数key,如此 key 和 共享ID绑定在一块
+    seg->ds.shm_segsz = size;	//共享段的大小
     seg->ds.shm_perm.cuid = LOS_GetUserID();	//设置用户ID
     seg->ds.shm_perm.uid = LOS_GetUserID();		//设置用户ID
     seg->ds.shm_perm.cgid = LOS_GetGroupID();	//设置组ID
@@ -285,10 +290,10 @@ STATIC INT32 ShmFindSegByKey(key_t key)
     INT32 i;
     struct shmIDSource *seg = NULL;
 
-    for (i = 0; i < g_shmInfo.shmmni; i++) {
+    for (i = 0; i < g_shmInfo.shmmni; i++) {//遍历共享段池,找到与key绑定的共享ID
         seg = &g_shmSegs[i];
         if ((seg->status & SHM_SEG_USED) &&
-            (seg->ds.shm_perm.key == key)) {
+            (seg->ds.shm_perm.key == key)) {//满足两个条件,找到后返回
             return i;
         }
     }
@@ -311,7 +316,7 @@ STATIC INT32 ShmSegValidCheck(INT32 segNum, size_t size, int shmFalg)
 
     return segNum;
 }
-//通过ID找到资源
+//通过ID找到共享内存资源
 STATIC struct shmIDSource *ShmFindSeg(int shmid)
 {
     struct shmIDSource *seg = NULL;
@@ -390,7 +395,7 @@ BOOL OsIsShmRegion(LosVmMapRegion *region)
 {
     return (region->regionFlags & VM_MAP_REGION_FLAG_SHM) ? TRUE : FALSE;
 }
-//使用共享段数量
+//获取共享内存池中已被使用的段数量
 STATIC INT32 ShmSegUsedCount(VOID)
 {
     INT32 i;
@@ -399,16 +404,16 @@ STATIC INT32 ShmSegUsedCount(VOID)
 
     for (i = 0; i < g_shmInfo.shmmni; i++) {
         seg = &g_shmSegs[i];
-        if (seg->status & SHM_SEG_USED) {
+        if (seg->status & SHM_SEG_USED) {//找到一个
             count++;
         }
     }
     return count;
 }
-//共享内存权限检查
+//对共享内存段权限检查
 STATIC INT32 ShmPermCheck(struct shmIDSource *seg, mode_t mode)
 {
-    INT32 uid = LOS_GetUserID();
+    INT32 uid = LOS_GetUserID();//当前进程的用户ID
     UINT32 tmpMode = 0;
     mode_t privMode = seg->ds.shm_perm.mode;
     mode_t accMode;

zzz/git/push.sh

 git add -A
-git commit -m  '完善共享内存几个结构体的注解.
+git commit -m  '开始注解(OOM)内存不足时的处理.
 搜索 @note_pic 方便理解画的字符图
 搜索 @note_why 尚未看明白的地方，如果您看明白了，请告知完善
 搜索 @note_thinking 一点思考和吐槽的地方

zzz/test/main.c

 #include <stdio.h>
 #include <stdarg.h>
+#include "turing.h"
 
-typedef unsigned int       UINTPTR;
-typedef unsigned char      UINT8;
-typedef unsigned long PTE_T;
-typedef unsigned long VADDR_T;
-#define IS_ALIGNED(a, b)                 (!(((UINTPTR)(a)) & (((UINTPTR)(b)) - 1)))
-
-typedef struct LOS_DL_LIST {
-    struct LOS_DL_LIST *pstPrev; /**< Current node's pointer to the previous node */
-    struct LOS_DL_LIST *pstNext; /**< Current node's pointer to the next node */
-} LOS_DL_LIST;
-
+LITE_OS_SEC_TEXT UINTPTR LOS_Align(UINTPTR addr, UINT32 boundary)
+{
+    if ((addr + boundary - 1) > addr) {
+        return (addr + boundary - 1) & ~((UINTPTR)(boundary - 1));
+    } else {
+        return addr & ~((UINTPTR)(boundary - 1));
+    }
+}
 void b(){
     UINT8 w[3]={0};
     PTE_T pte1BasePtr = 0x11100000;
     VADDR_T vaddr = 0x80738903;  
-
-    #define MMU_DESCRIPTOR_L1_SMALL_SIZE                            0x100000 //1M
-    #define MMU_DESCRIPTOR_L1_SMALL_MASK                            (MMU_DESCRIPTOR_L1_SMALL_SIZE - 1)
-    #define MMU_DESCRIPTOR_L1_SMALL_FRAME                           (~MMU_DESCRIPTOR_L1_SMALL_MASK)
-    #define MMU_DESCRIPTOR_L1_SMALL_SHIFT                           20
-    #define MMU_DESCRIPTOR_L1_SECTION_ADDR(x)                       ((x) & MMU_DESCRIPTOR_L1_SMALL_FRAME)
-    #define OS_TSK_HIGH_BITS       3U
-    #define OS_TSK_LOW_BITS        (32U - OS_TSK_HIGH_BITS) //29
-    #define OS_TSK_SORTLINK_LOGLEN OS_TSK_HIGH_BITS	//3U
-
     PTE_T  l1Entry = pte1BasePtr + vaddr >> MMU_DESCRIPTOR_L1_SMALL_SHIFT;
     printf("pte1BasePtr ad: %x\n",&pte1BasePtr);
     printf("w[1] ad: %x\n",&w[1]);
@@ -35,19 +23,12 @@ void b(){
     printf("MMU_DESCRIPTOR_L1_SMALL_FRAME:%x\n",MMU_DESCRIPTOR_L1_SMALL_FRAME);
     printf("pa: %x\n",MMU_DESCRIPTOR_L1_SECTION_ADDR(l1Entry) + (vaddr & (MMU_DESCRIPTOR_L1_SMALL_SIZE - 1)));
 }
-
 void a(){
-    #define BITMAP_BITS_PER_WORD (sizeof(UINTPTR) * 8)
-    #define BITMAP_NUM_WORDS(x) (((x) + BITMAP_BITS_PER_WORD - 1) / BITMAP_BITS_PER_WORD)
     printf("BITMAP_BITS_PER_WORD %d\n",BITMAP_BITS_PER_WORD);
     printf("BITMAP_NUM_WORDS %d\n",BITMAP_NUM_WORDS(1UL << 8));
 }
 
 void round1(){
-    #define PAGE_SIZE                        (0x1000U) // 页大小4K
-    #define ROUNDUP(a, b)                    (((a) + ((b) - 1)) & ~((b) - 1))
-    #define ROUNDDOWN(a, b)                  ((a) & ~((b) - 1))
-    #define ROUNDOFFSET(a, b)                ((a) & ((b) - 1))
     int a = 0xFF;
     //printf("a>> %d\n",a>>3);
     //printf("a/ %d\n",a/8);
@@ -77,13 +58,14 @@ void arg_test(int i, ...)
 }
 int main()
 {
-    int size = 0;
-    printf("sizeof(int) %d\n",sizeof(int));
-    round1();
+    int size = 4097;
+    size = LOS_Align(size, PAGE_SIZE);//必须对齐
+    printf("sizeof(int) %d\n",size);
+    //round1();
     //arg_test(99, 4,8,9);
     //size = sizeof(LOS_DL_LIST) << OS_TSK_SORTLINK_LOGLEN;
     //printf("LOS_DL_LIST %d\n",sizeof(LOS_DL_LIST *));
     //printf("size %d\n",size);
     return 0;
 }
-
+// gcc -o main main.c

zzz/test/turing.h

+
+
+typedef unsigned int       UINTPTR;
+typedef unsigned char      UINT8;
+typedef unsigned short     UINT16;
+typedef unsigned int       UINT32;
+typedef unsigned long PTE_T;
+typedef unsigned long VADDR_T;
+#define IS_ALIGNED(a, b)                 (!(((UINTPTR)(a)) & (((UINTPTR)(b)) - 1)))
+#define PAGE_SIZE                        (0x1000U) // 页大小4K
+#define ROUNDUP(a, b)                    (((a) + ((b) - 1)) & ~((b) - 1))
+#define ROUNDDOWN(a, b)                  ((a) & ~((b) - 1))
+#define ROUNDOFFSET(a, b)                ((a) & ((b) - 1))
+#define MMU_DESCRIPTOR_L1_SMALL_SIZE                            0x100000 //1M
+#define MMU_DESCRIPTOR_L1_SMALL_MASK                            (MMU_DESCRIPTOR_L1_SMALL_SIZE - 1)
+#define MMU_DESCRIPTOR_L1_SMALL_FRAME                           (~MMU_DESCRIPTOR_L1_SMALL_MASK)
+#define MMU_DESCRIPTOR_L1_SMALL_SHIFT                           20
+#define MMU_DESCRIPTOR_L1_SECTION_ADDR(x)                       ((x) & MMU_DESCRIPTOR_L1_SMALL_FRAME)
+#define OS_TSK_HIGH_BITS       3U
+#define OS_TSK_LOW_BITS        (32U - OS_TSK_HIGH_BITS) //29
+#define OS_TSK_SORTLINK_LOGLEN OS_TSK_HIGH_BITS	//3U
+#define BITMAP_BITS_PER_WORD (sizeof(UINTPTR) * 8)
+#define BITMAP_NUM_WORDS(x) (((x) + BITMAP_BITS_PER_WORD - 1) / BITMAP_BITS_PER_WORD)
+#ifndef LITE_OS_SEC_TEXT
+#define LITE_OS_SEC_TEXT        /* __attribute__((section(".text.sram"))) */
+#endif
+typedef struct LOS_DL_LIST {
+    struct LOS_DL_LIST *pstPrev; /**< Current node's pointer to the previous node */
+    struct LOS_DL_LIST *pstNext; /**< Current node's pointer to the next node */
+} LOS_DL_LIST;
\ No newline at end of file